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Table of Contents Coral Reef Cart Collection Acknowledgments................................................................................................................................. 1 Cart Materials and Presentation ............................................................................................................ 2 Maple Cart and Collection Care ........................................................................................................... 3 Objectives of the Coral Reef Cart Collection ....................................................................................... 4 Coral Biology ........................................................................................................................................ 5 Coral Reef Collection Specimens ......................................................................................................... 7 Themes and Concepts ........................................................................................................................... 8 What is a Coral? ................................................................................................................................ 8 Feeding Strategies ............................................................................................................................. 9 Defensive Strategies........................................................................................................................ 12 Commensalism................................................................................................................................ 15 Coral predators ................................................................................................................................ 16 Specimen Descriptions....................................................................................................................... 17 Porifera: Sponges ............................................................................................................................ 17 Cnidarians: Octocorallia ................................................................................................................. 19 Alcyonacea: Soft Corals and Gorgonians ................................................................................. 19 Cnidarians: Hexacorallia ................................................................................................................. 22 Scleractinia: Stony Corals ......................................................................................................... 22 Mollusks: Gastropods ..................................................................................................................... 28 Cone Snail .................................................................................................................................. 28 Tiger Cowrie .............................................................................................................................. 30 Murex ......................................................................................................................................... 32 Triton’s Trumpet ........................................................................................................................ 34 Mollusks: Bivalves.......................................................................................................................... 36 Tridacna Clam ............................................................................................................................ 36 Mollusks: Cephalopods................................................................................................................... 38 Cuttlefish .................................................................................................................................... 38 Chambered Nautilus................................................................................................................... 41 Octopus ...................................................................................................................................... 44 Arthropods ...................................................................................................................................... 47 Hermit Crabs .............................................................................................................................. 47 Echinoderms ................................................................................................................................... 49 August 2010 1 Sea Stars ..................................................................................................................................... 49 Sea Urchins ................................................................................................................................ 52 Vertebrates: Cartilaginous Fishes ................................................................................................... 54 Rays............................................................................................................................................ 54 Sharks......................................................................................................................................... 58 Vertebrates: Bony Fishes ................................................................................................................ 62 Parrotfishes ................................................................................................................................ 62 Pufferfishes ................................................................................................................................ 64 Triggerfish.................................................................................................................................. 66 Seahorses.................................................................................................................................... 68 Appendix: In the Academy ................................................................................................................. 70 2 DRAFT August 2010 Acknowledgments The Coral Reef collection was created in the fall of 2008 to provide Academy docents the opportunity to showcase the new iconic Philippine Coral Reef Aquarium and to enhance the public’s understanding of the diversity of species associated with tropical coral reefs Initial specimens in this collection were assembled as part of early coral reef training workshops, with the assistance of docents Ingrid Oyen and Delcey Watkins. Nancy Elenberger assumed primary responsibility for this collection in the fall of 2009, and we owe her special thanks for her enthusiastic contribution to the current specimen collection, supporting photos and diagrams, and more emphatically, for her extensive efforts in researching vetted sources for the material contained in this document. Additional thanks to Jill Ross-Kuntz, who developed the section on “Themes and Concepts.” Finally, always special thanks to Academy’s docent staff Kathleen Lilienthal and Velma Schnoll, whose constant guidance and support are critical to the maintenance of this collection. New material was vetted by _________________ in 2010. Jacqueline Craig Cart Team Chair August 2010 1 Cart Materials and Presentation GOAL The goal of cart presentations is to engage visitors in exploration and discovery. Cart Collection specimens are chosen for their attractiveness to the public, their availability, their teaching potential (both singly and/or combined with other specimens), and their durability and safety for handling. Research has shown that visitors will have a more positive experience when they have personal interactions with a person representing the Academy. PURPOSE To stimulate curiosity and understanding by giving visitors a docent-guided opportunity to examine and learn from real specimens. To offer a unique, engaging hands-on exploration. To provide insight into Academy exhibits and concepts. PRESENTING A CART Place the cart where there is good light, high visibility, and doesn’t block pathways, emergency information, or fire apparatus (see map). Look interested and eager – show that you want to talk with visitors. Look outward to visitors rather than reading material. Be enthusiastic – about the cart material, your theme, the Academy. Stay with your cart. Get someone to stay with your cart if you need to take a break. BEFORE YOU BEGIN Prepare in advance. Choose a theme for which you have been trained and that can be supported by available specimens. (Cart binders include information describing themes for presenting specimens on the public floor.) Study background information before presenting the cart. Highlight only one or two concepts or themes. Choose hands-on items that best support themes using no more than 4-6 specimens (only vetted specimens can be taken on to the pubic floor). AFTER YOUR SHIFT Replace materials in their proper boxes or shelf in the cart or cabinets. Return support information or pictures to binder/files. Lock and return cart/bins to proper location (maple carts should be turned so that rear of cart faces the floor and that mirror does not face the exterior). Use Damage Specimen Report Form to report any missing/damaged specimens to Docent Program Staff (send email notice to cart monitor and leave a copy of report in the binder). Coral Reef Cart Monitors: Nancy Ellenberger and Carrie O’Connell 2 DRAFT August 2010 Maple Cart and Collection Care MAPLE CART COLLECTIONS Maple Carts are stored at opposite ends of the Academy and should be turned with the drawers to the windows, but the mirror should be turned inward so that birds are not attracted. Drawers should be locked when not in use. Cart drawers are lined with appropriate drawer liners to reduce sliding as drawers and cart are moved. Each drawer contains labels indicating where specimens are stored. Specimens should be returned to appropriate drawers after cart presentation. Fragile specimens should be returned to their labeled boxes or wrapped in bubble wrap. OTHER CART COLLECTIONS Several cart collections are stored in various locked cabinets in the first level. Maple carts may be used to present these specimens when maple cart collections are not being presented by another docent. Specimens must be returned to locked cabinets after use. FABRIC Cart fabric is provided in the day lounge to cover tops of carts. This is to reduce sliding of specimens on cart surface and to give a consistent presentation to the public. DEMONSTRATION STATIONS Demonstration stations may also be used for displaying collections. Specimens may be placed on top of table. Demonstration stations may require cleaning before storing. August 2010 3 Objectives of the Coral Reef Cart Collection Provide the visitor an opportunity for an active and interactive experience—at all age levels. Provide the visitor with an opportunity to engage in conversations and to ask questions related to the coral reef environment. Provide an introduction to the complex coral reef community Provide specific information about specimens of the collection, as well as about live coral reef organisms in other parts of the Academy and to encourage the visitor to look for these organisms. Encourage the visitor to have an interest in coral reefs beyond the Academy experience. 4 DRAFT August 2010 Coral Biology1 Corals are cnidarians (also known as coelenterates), and are related to hydroids, jellyfish, box jellies, and sea anemones. Corals in these tanks include: Hexacorallia – the hard (stony) corals are perhaps the best-known group, as they secrete calcium carbonate skeletons and are the reef-builders. They have six tentacles (or multiples of six). Octocorals - the soft corals have eight tentacles and lack an external skeleton, having instead internal skeletons consisting of separate, unfused spicules of calcium carbonate within their tissues or with axes of a dark protein called gorgonin. Hydrocorals – these include the fire or stinging, corals. They are not true corals (they occupy a different class “Hydrozoa”). Although they look like real corals, they are more closely related to jellyfish and other stinging anemones. Cnidarians are characterized by having alternating lifestyles, existing either as a polyp, the sessile attached stage, or as a medusa, the free-floating jellyfish-like stage. Most corals are colonial, often living in communities of astonishing numbers of individuals, though a few forms, such as the mushroom coral, are solitary. All corals have supporting structures, formed of calcium carbonate or of a fibrous protein or both. The coral polyp is a relatively simple organism with a hollow, cylindrical structure, its bottom end attached to its skeleton in the case of stony corals, or in the case of octocorals, to the substrate. At the upper end is a single opening surrounded by tentacles armed with specialized stinging structures, called nematocysts, used to paralyze prey. This opening functions both as mouth and anus, ingesting food and excreting waste. Coral shapes and sizes vary greatly among species. General appearance varies from boulder-like spheres of brain coral to the branching staghorn, and beyond that to the plate-like elkhorn. Soft corals are more flexible, often waving gracefully in the currents. Morphology is often affected by depth, and exposure to light and currents. MUTUALISTIC RELATIONSHIP: ZOOXANTHELLAE In the photic zone, light penetrates to fuel the photosynthesis of symbiotic algae, a species of dinoflagellates collectively called zooxanthellae, that live within the corals’ tissue. The relationship between coral and algae is mutualistic, benefiting both partners and is the driving force behind the productivity of the reef system. 1 See “The Philippine Coral Reef” training document, November 2008. August 2010 5 Corals provide zooxanthellae with protected living space and nutrients necessary for photosynthesis. A significant part of coral nutrition is provided by their algal symbionts that produce sugars and amino acids used by the coral to manufacture the proteins and complex carbohydrates to fuel its activities. The algae are so productive that up to 90% of the organic material they manufacture is available to and used by their coral hosts The algae enrich the waters of the reef with oxygen, their photosynthetic by-product. The health of stony corals and their ability to secrete sufficient CaCO3 is dependent on the energy produced by their tiny partners. The very existence of coral reefs relies on this relationship. Much of the color of reef corals is usually created not by the coral itself, but by the various species of zooxanthellae, which typically range from yellow, to brown, and green. The few species with bright colors such as red, orange and yellow generally do not harbor zooxanthellae. All hard corals, fire corals, and many octocorals maintain this symbiotic relationship. CORAL REPRODUCTION Sexual reproduction During sexual reproduction, some species produce eggs that are fertilized internally and brooded either inside or outside the parent. Many species broadcast both eggs and sperm, usually with timing synchronized within the entire colony or even with reefs in the general vicinity, to ensure cross-fertilization. Planktonic larvae are then dispersed in the currents, and the few that survive predation and other misfortune develop into the polyp stage if they successfully settle on a suitable reef or other substrate. Asexual reproduction Corals also reproduce by budding. When it reaches a certain size, the parent polyp divides, producing a clone that expands the original colony or begins a new colony. Because of clonal reproduction, many individuals in a coral community are genetically identical, a condition that persists over long periods of time. 6 DRAFT August 2010 Coral Reef Collection Specimens PORIFERA Venus flower basket sponge Sponge from Jamaica Misc. sponge CNIDARIANS: OCTOCORALLIA (SOFT CORALS) Common sea fan Misc. Gorgonia CNIDARIANS: HEXACORALLIA (HARD CORALS) Brain coral Mushroom coral Pocillopora Turbinaria reniformis MOLLUSKS: GASTROPODS Misc.cone snail Tiger cowrie shell Misc. murex shell Triton’s trumpet MOLLUSKS: BIVALVES Tridacna clam (ruffled?) ARTHROPODS Hermit crabs ECHINODERMS: SEA STARS Blue linkia sea star Chocolate chip sea star ECHINODERMS: URCHINS Pencil urchin Misc. test (?) VERTEBRATES: CARTILAGINOUS FISHES Ray barbs Sand shark jaw VERTEBRATES: BONY FISHES Parrotfish lower jaw Porcupine fish spines Porcupinefish Triggerfish skull Triggerfish skeleton Seahorses MOLLUSKS: CEPHALOPODS Cuttlefish bone and dwarf cuttlefish bones Full nautilus shell and sliced nautilus shells Octopus’ beak August 2010 7 Themes and Concepts WHAT IS A CORAL? SPECIMENS HARD CORALS colonial (Pocillopora, brain coral, Turbinaria) solitary (mushroom coral) SOFT CORAL (GORGONIAN) SUPPORTING MATERIALS diagram of coral structure. photographs of various coral species. GENERAL INFORMATION See earlier section, “Coral Biology,” page 5. THINGS TO NOTICE/FACTS TO SHARE Stony structure of hard coral is composed of calcium carbonate. These are reef-building corals. Note the diversity of shapes. Coral shapes are influenced by their surroundings and the energy of their water environment. Examples of corals in high energy environments are brain or mushroom corals. Finely branched corals typically inhabit low energy environments. Gorgonian and sea fan are soft corals with skeletons composed of a protein called gorgonin or calcium carbonate spicules. This allows for flexibility in a high-energy environment. Multiple, small holes in Pocillopora and Turbinaria are where each individual polyp in the colony lived. When feeding, the polyps emerge from the holes, and the entire living colony covers the calcium carbonate shell. (See diagrams and photographs). Brain coral has valleys and ridges. The polyps reside in the valleys. Compare colonial coral specimens to solitary mushroom coral that consists of a single organism. When its tentacles emerge, it resembles a sea anemone. Since it is only one animal, it has only one mouth. 8 DRAFT August 2010 FEEDING STRATEGIES CARNIVOROUS ORGANISMS SPECIMENS hard coral sandbar shark jaw triggerfish skull octopus beak Linkia seastar chocolate chip sea star murex shells Triton’s Trumpet shell cone snail shell sea horses SUPPORTING MATERIALS photographs of organisms shark models THINGS TO NOTICE/FACTS TO SHARE Corals have tentacles with stinging cells called nematocysts. They catch small fish and zooplankton using these stinging cells. At night the coral polyps emerge for feeding. Shark jaw. The teeth are not lodged permanently within the jaw, but are attached to a membrane known as a tooth bed. The tooth bed is like a conveyor belt, moving the rows of teeth forward as the shark grows, thus replacing older teeth that have become damaged, fallen out or worn down. Octopus beak. Diet is mainly crustaceans and molluscs, plus fish and other octopuses. The octopus uses its beak to drill into the shell of its prey. It secretes a toxin that paralyses the prey and begins to dissolve it. The shell is pulled apart and the prey is consumed. Note: the cuttlefish and Nautilus are also carnivorous cephalopods. Sea stars. They feed on molluscs, using their tube feed to pry open the shell a little. Then they insert their stomach into the shell and digest the organism externally. Triggerfish. Uses strong teeth to consume sponges, molluscs and crustaceans. Cone snail. Uses its harpoon-like radula to inject venom into its prey, typically another cone snail. An extension of its shell acts like a rifle barrel. Researchers have discovered that certain chemicals in cone snail venom have the potential to treat chronic pain, cancer and other afflictions. One synthetic drug developed may be a thousand times more effective than morphine without any of its addictive properties. Murex and Triton’s trumpet are carnivorous snails. They bore a hole in the shell or outer covering of their prey in order to consume it. Murex snails eat other molluscs. Triton’s trumpet snails eat sea stars, including the Crown of Thorns sea star, and release a paralysing saliva to subdue their prey. Sea horses. Their long snout can only open at the tip. It feeds on small organisms by opening its mouth to create suction that draws its prey into its mouth. August 2010 9 FILTER FEEDERS SPECIMENS gorgonian coral sponges ruffled clam shell SUPPORTING MATERIALS photographs of organisms manta ray model THINGS TO NOTICE/FACTS TO SHARE Sponges. Sponges are primitive, sessile, mostly marine, aquatic filter feeders that pump water through their bodies to filter out particles of food matter. Ruffled clam. Clams are filter feeders, ingesting nutritious plankton and micro-organisms that are pumped in and out through “siphons”. Gorgonian corals are considered filter feeders because they turn their “fan” so that it is oriented across the prevailing current. This facilitates the catching of plankton and particulate matter. Manta rays are large rays averaging 22 feet wide. They are found in tropical waters and eat microscopic plankton, small fish and tiny crustaceans. Manta rays filter-feed in open water by funneling food into their mouth while they swim, using two large, flap-like cephalic lobes that extend forward from the eyes. They have a short tail and no stinging spine. HERBIVORES SPECIMENS pencil sea urchin cowrie shell parrotfish jaw SUPPORTING MATERIALS photographs of organisms THINGS TO NOTICE/FACTS TO SHARE Pencil sea urchin. Sea urchins graze on algae using a specialized mouth part called Aristotle’s lantern. This organ is located on the underside of the urchin and is made up of five carbonate teeth with a fleshy tongue-like structure within. Cowrie snail. This snail grazes on algae using its sandpaper-like radula. Parrotfish. This fish uses its parrot-like jaws to rasp algae from coral and other substrates (bioerosion). It is considered to be herbivorous but will eat a variety of reef organisms including coral polyps. After digestion, it excretes the broken down rock as sand, thus creating small islands and sandy beaches. One fish can produce 90 kg of sand per year. The teeth grow continuously. 10 DRAFT August 2010 INTERPRETATION IDEAS COMPARE parrotfish jaws triggerfish jaws shark jaws octopus beak DISCUSS PREDATOR PREY RELATIONSHIPS Triton’s Trumpet/Crown of Thorns Triton’s Trumpet/Blue Linkia sea star octopus/hermit crab pufferfish/blue Linkia sea star pufferfish/urchins, corals triggerfish/urchins triggerfish/Tridacna clams octopus, shark, triggerfish/Nautilus sharks/pufferfish hammerhead sharks/rays August 2010 11 DEFENSIVE STRATEGIES VENOM/TOXINS SPECIMENS ray barbs spiny puffer fish sponges (not Venus Flower Basket) octopus beak octopus model ray model SUPPORTING MATERIALS photographs of organisms THINGS TO NOTICE/FACTS TO SHARE Ray barb or stinger is a modified dermal denticle on the tail. It is used exclusively in selfdefense. The underside has two grooves with venom glands. The stinger is covered with a thin layer of skin (the integumentary sheath) in which the venom is concentrated. The puffer fish is the second most poisonous vertebrate in the world after the Golden Poison Frog. Its ovaries and liver contain a neurotoxin, tetradotoxin. Smaller amounts are present in the intestines and skin. This neurotoxin is particularly toxic to humans. Some fish, such as tiger sharks, can eat puffer fish without harm. The neurotoxin may be produced by bacteria obtained in the fish’s diet. The toxicity can be prevented by controlling the diet in captivity. Sponges produce toxins that prevent other sessile animals such as bryozoans or sea squirts from growing on or near them, making them effective competitors for living space. (The Venus Flower Basket is a deepwater sponge and does not produce any toxin.) After the octopus has drilled into the shell of a mollusc with its beak, it secretes a toxin that paralyses the prey and begins to dissolve it. NON-VENOMOUS PROTECTION SPECIMENS gastropod shells spiny puffer fish porcupine fish spines hermit crabs pencil sea urchin nautilus shell ruffled clam shell sea horses sea stars SUPPORTING MATERIALS photographs of organisms hermit crab model 12 DRAFT August 2010 THINGS TO NOTICE/FACTS TO SHARE The gastropod shells provide protection from predators. They are composed of calcium carbonate. Notice the variety in the shell sizes and shapes. The smooth surface of the cowrie shell is due to its being mostly covered by the mantle when the animal is alive. This prevents other organisms from attaching to it. The spiny puffer fish is able to inflate its body using water or air, making it difficult to swallow. The spines on its body serve the same function. The porcupine fish’s spines are particularly sturdy and protect it from being swallowed by predators. Hermit crabs utilize empty shells as a home to protect themselves from predators. When they outgrow their shell they must find a larger one and transfer into it. The spines on the outer surface of the pencil sea star make it difficult to eat. The double shells of the ruffled clam protect it from predators and can close up if the animal is threatened, although it is unable to close its shell completely. The outer covering of sea horses has no scales. Their bodies are covered by thin skin stretched over bony plates that are arranged in rings throughout the body. The bony plates make their outer covering hard and difficult to bite through. Sea stars have an outer body composed of calcium carbonate components known as ossicles. This makes their outer surface hard to penetrate. Several groups of sea stars possess pincerlike structures known as pedicillaria that may be used in defense. Sea stars are able to regrow lost arms. They can autotomize one or more arms to avoid predation. Sea stars can autotomize more than 75% of their body mass and continue to survive. CAMOUFLAGE/COLOR SPECIMENS cuttlefish “bone” octopus beak sea horses ray model shark model octopus model SUPPORTING MATERIALS photographs of organisms THINGS TO NOTICE/FACTS TO SHARE Both the octopus and cuttlefish are capable of changing color and texture to blend in with their surroundings. Sea horses use their prehensile tails to hang on to vegetation and their coloration blends with the colors of the plants. Notice that the dorsal surface of the toy ray and shark is a dark color, while the ventral surface is light. This is known as “counter-shading” and enables the animal to be camouflage August 2010 13 from above and below. From above it blends in with the dark ocean floor and from below it blends in with the bright sky above it. 14 DRAFT August 2010 COMMENSALISM SPECIMENS hard coral gorgonian coral hermit crabs Venus Flower Basket sponge ruffled clam SUPPORTING MATERIALS photographs of organisms THINGS TO NOTICE/FACTS TO SHARE Most corals (both hard and soft) obtain most of their energy and nutrients from photosynthetic, unicellular algae called zooxanthellae that live within their tissues. Such corals require sunlight and grow in clear, shallow water typically at depths shallower than 60 m (200 ft). These algae are responsible for the coloration of the coral. A species of fish called a shrimpfish often lives within gorgonian corals. Their slender bodies blend in with the coral skeleton. A hermit crab may attach a sea anemone to its shell. The stinging tentacles of the anemone give the crab added protection and the anemone benefits by eating particles of the crab’s food. The Venus Flower Basket is a deepwater sponge. A pair of shrimp (male and female) live within the sponge, unable to escape the basket. The shrimp clean the inside of the basket and in return the sponge provides food for the shrimp by trapping it in its fiberglass-like strands and releasing it in to the body of the sponge. The sponge contains bioluminescent bacteria that may attract small organisms for the shrimp to eat. The shrimp will breed and their tiny offspring escape to find a Venus Flower Basket of their own. Observe the ruffled clam and note that giant (Tridacna) clams contain symbiotic zooxanthellae that provide them with food by photosynthesis. The beautiful colors of the giant clam mantle are due to these algae. August 2010 15 CORAL PREDATORS SPECIMENS parrotfish jaws Triton’s Trumpet shell pencil sea urchin test photograph of live Triton’s Trumpet shell photograph of live parrotfish SUPPORTING MATERIALS photograph of Crown of Thorns sea star THINGS TO NOTICE/FACTS TO SHARE Parrotfish use their strong jaws to rasp algae from coral and other hard substrates. They may consume coral polyps and erode the stony skeleton of the reef. The Crown of Thorns is a large sea star that feeds on coral. The Triton’s Trumpet snail feeds on the Crown of Thorns sea star. The Crown of Thorns can detect the approach of a Triton’s Trumpet by means not clearly understood and will attempt flight before any physical contact had taken place. 16 DRAFT August 2010 Specimen Descriptions PORIFERA Sponges SPECIMENS Venus Flower Basket sponge sponge from Jamaica common sponge GENERAL INFORMATION CLASSIFICATION Phylum Porifora DISTRIBUTION About 8,000 species are found in marine habitats throughout the world. HABITAT Some sponges grow only in warm shallow seas, but other species are found from the intertidal to the deep ocean. About 150 species grow in freshwater. APPEARANCE Sponges are considered to be the simplest of the multi-cellular animals because they lack tissues and organs. They exhibit organization at the cellular level with different cells specialized for various functions: feeding, protection, support, or reproduction. Most sponges attach to hard substrates and exhibit a good deal of variation. They come in many colors and are asymmetrical. Some are low, encrusting forms. Others are shaped like vases or tubes, mostly small, but a few with central openings large enough to hold a diver. Sponges have skeletal elements called spicules that help maintain their structure and may be composed of calcium carbonate, silica, or an organic material called spongin. DIET Sponges filter feed on minute organic particles suspended in the water. The sponge draws water in through small exterior pores by means of the rhythmic beating of whip-like flagella on its collar cells. The collar cells trap food and then pass it to amoeba-like cells prowling between the sponge lining which engulf and process the food. Water then exits through a single central opening. Oxygen and carbon dioxide exchange occurs through this process as well. PREDATORS Various marine snails, sea stars, fishes, and other animals prey on sponges. August 2010 17 DEFENSIVE STRATEGIES Many sponges have hard skeletons, and some produce toxins to deter predators. A few of these toxic substances are being studied as sources of drugs for the treatment of cancer and other diseases. REPRODUCTION AND DEVELOPMENT Specialized cells produce flagellated sperm and immobile eggs; fertilization may be external or take place in the interior cavity of the sponge. The embryo becomes a free-swimming larva that eventually settles out, attaches to an appropriate substrate, and metamorphoses into a young sponge. CONSERVATION STATUS Earlier in the century, natural bath sponges were gathered and sold in great quantities. Today, due to past over harvesting and epidemic disease, their availability is greatly reduced. Even with the production of low-cost synthetic sponges, the natural forms are prized and expensive. TO NOTICE Notice the difference in color, texture, and structure between the specimens. Show photos of live sponges in their habitats. Point out different colors and shapes. SPECIMEN DETAIL Venus Flower Basket Euplectella aspergillium (Glass Sponges) Habitat: Most glass sponges live in deep waters. Appearance: This specimen is an example of a skeleton made of hard spicules. Remarks: Certain bioluminescent shrimp tend to form a symbiosis with the Venus flower basket sponge. The sponge houses two small shrimp, a male and a female, who live out their lives inside the sponge. They breed, and when their offspring are tiny, the offspring escape to find a Venus flower basket of their own. The shrimp inside of the basket clean it, and, in return, the basket provides food for the shrimp by trapping it in its fiberglass-like strands and then releasing it into the body of the sponge for the shrimp. Because of the shrimp inside, the Japanese viewed the Venus flower basket as a symbol of wedded bliss. 18 DRAFT August 2010 CNIDARIANS: OCTOCORALLIA Alcyonacea: Soft Corals and Gorgonians SPECIMENS common sea fan gorgonian GENERAL INFORMATION CLASSIFICATION Phylum Cnidaria, Class Anthozoa, Subclass Octocorallia, Order Alcyonacea Note that the subclass Octocorallia also includes Order Helioporacea (Blue Coral) and Order Pennatulacea (Sea Pens) DISTRIBUTION Octocorals are found in all the world’s oceans. The greatest diversity is in the tropical western Pacific. HABITAT Octocorals are found in both shallow tropical marine habitats as well as in deep benthic communities. APPEARANCE AND BEHAVIOR All octocorals have eight feather-like tentacles that surround the mouth of each polyp. These tentacles are often fringed and contain nematocysts which are used for protection and to incapacitate prey. Colonies are usually attached to the substrate at a single point at the base of a stem and most species have some form of branching. They may resemble fans, bushes, and whips. In addition, some colonies are encrusting. Although they don't secrete calcium carbonate as prolifically as hard corals, soft corals do contain spiny skeletal elements called sclerites that are found in the jelly-like tissue between polyps. Sclerites are made of protein and calcium carbonate and give soft coral support to allow them to achieve their vertical structures. The sclerites also give their surfaces a spiky or grainy texture. The inner core of a soft coral may also contain gorgonin; a flexible, fibrous protein. This gives the soft corals that contain it the ability to flex with the ocean waves and currents. When a soft coral animal dies, its tissue decomposes and disappears. The exceptions to this are gorgonian, blue coral, and organ pipe coral. DIET Some soft corals have zooxanthellae that provide glucose, glycerol and amino acids to the corals. Some soft corals do not contain zooxanthellae and feed on zooplankton and debris only. August 2010 19 The branching shape and large size of many octocorals helps their polyps capture food from the water as it passes by the colony PREDATORS Many soft corals exude mucus with traces of chemicals that repel other organisms, such as sponges and algae which might otherwise grow too close or over the top of the corals. Brittle stars and marine worms that live on the octocoral in order to have better access to food particles may feed on the coral themselves. REPRODUCTION AND DEVELOPMENT Three types of reproduction occur in octocorals: broadcasting of eggs and sperm, internal brooding of larvae, and external brooding of larvae. REMARKS Some of the soft corals produce substances such as terpenoids that are being studied for their toxic effects on human cancer cells. TO NOTICE Mention that most soft corals would not leave behind a complete skeleton, but gorgonians do. Notice the shape of the gorgonians and how that shape would enable them to have contact with the water for nourishment purposes. Point out that the sea fan would be at right angles to the current. Mention that the live sea fan would have a different color. Show photo. Show photo of deep water gorgonians that resemble the misc. gorgonian. SPECIMEN DETAIL Common Sea Fan Gorgonia ventalina Distribution: It is found from Bermuda to Curacao, including the Florida Keys and Western Caribbean. However, it is not found in the Gulf of Mexico. Habitat: It is primarily found on band and patch reefs. In addition, it can be found in nearshore areas with heavy wave action and also on deeper reefs. Appearance: The sea fan can grow to be 180 cm by 150 cm. It is usually purple but can vary to its less common colors of yellow-orange, yellow, and brown. The pigments are in the spicules. The polyps are white. The common sea fan will orient so that the "fan" is perpendicular to the motion of the waves. This orientation only occurs in the adult sea fans. The young will grow in any direction, but as they mature will slowly shift until they are facing the current. When the tentacles of live polyps are extended they almost touch each other across the spaces and any small drifting creature has little hope of passing through without getting caught Diet: It is carnivorous, feeding on zooplankton, especially at night. Also, derives nourishment from its zooxanthellae. 20 DRAFT August 2010 Predators: The carnivorous gastropod Cyphoma preys on octocorals such as the sea fan. The sea fan does have chemical defenses that somewhat reduce this predation. The nudibranch T. hamnerorum also feeds on the sea fan in order to acquire these chemical compounds so it can defend itself against predators. When infected by the fungus Aspergillus, the sea fan will respond with more sclerites in the area to contain the fungus. Mortality: The lifespan is unknown. Most commonly gorgonian corals are destroyed by wave energy or by overgrowth of organisms, such as encrusting bryzoans and fire coral. Reproduction: Gorgonian corals reproduce asexually by cloning or fragmentation, with external fertilization. The larvae typically spend several days as plankton before settling on a hard surface to begin formation of a colony Conservation: The sea fan is officially protected in some coral reef areas. Remarks: The sea fan is popularly collected for use in aquariums and as souvenirs. As a colorful addition to coral reef habitats, its presence also is important to ecotourism Gorgonian (species unknown) The shape of this gorgonian is a contrast to the Common Sea Fan gorgonian. Since its exact name is unknown, below is some general information about gorgonians. Distribution: Gorgonians are found throughout the oceans of the world, especially in the tropics and subtropics. Habitat: Gorgonians are found in shallow waters, though some have been found at depths of several thousand feet. Appearance: They can be whip-like, bushy, or even encrusting. They can be brightly colored, often purple, red, or yellow. They may be up to several feet high. The more fan-shaped and flexible gorgonians tend to populate shallower areas with strong currents, while taller, thinner, and stiffer gorgonians can be found in deeper, calmer waters. Diet: Some gorgonians have zooxanthellae and derive some or most of their nutrition from them. Others, especially deep water gorgonians, use only their polyps to capture food. Most gorgonian polyps are expanded during the day for feeding, rather than at night. Remarks: Other fauna such as hydrozoa, bryozoa, and brittle stars are known to live within the branches of gorgonian colonies. August 2010 21 CNIDARIANS: HEXACORALLIA Scleractinia: Stony Corals SPECIMENS Acropora sp. brain coral (also photo of large brain coral) mushroom coral Pocillopora Turbinaria sp. SUPPORTING MATERIALS photo of brain coral GENERAL INFORMATION CLASSIFICATION Phylum Cnidaria, Class Anthozoa, Subclass Hexacorallia, Order Scleractinia DISTRIBUTION AND HABITAT Colonial stony corals are found in clear, shallow tropical waters; they are the world's primary reef-builders. Most reefs are found between 30° north and 30° south latitudes. Solitary stony corals are found in all regions of the oceans and do not build reefs. Some live in temperate, polar waters, or below the photic zone down to 6000 meters. APPEARANCE AND BEHAVIOR All coral polyps have a gastrovascular cavity that opens at only one end (the mouth) where food is consumed and some waste products are expelled. They also have a circle of tentacles around the mouth that help the coral capture and ingest food, clear away debris, and act as a primary means of defense. Scleractinia coral have six (or multiples of six) tentacles. One important cell structure corals have is a cnidocyte. These contain organelles called cnidae which include nematocysts—a type of stinging cell. These are capable of delivering powerful, often lethal toxins, essential to capturing prey and facilitating interactions between corals. Corals contain symbiotic algae called zooxanthellae within their gastrodermal cells. The coral provides the zooxanthellae with a protected environment and the compounds necessary for photosynthesis (carbon dioxide, nitrates and phosphates). The algae provide the coral with oxygen, help remove wastes, and provide food. Each stony coral polyp secretes a skeleton of calcium carbonate. The skeletons are secreted by the lower portion of the polyp. This process produces a cup, called the calyx, in which the polyp sits. The walls surrounding the cup are called the theca and the floor is called the basal plate. Thin, calcareous septa extend upward from the plate and provide protection for each 22 DRAFT August 2010 polyp. Periodically, a polyp will lift off its base and secrete a new floor to its cup, forming a new basal plate above the old one. This creates a minute chamber in the skeleton. While the colony is alive, calcium carbonate is deposited, adding partitions and elevating the coral. When polyps are stressed, they contract into the calyx. The yellow to brown color of most corals comes from the zooxanthellae in their tissue, but some corals contain protective pigments that give them bright colors. These pigments help shield the DNA of the coral from the destructive effects of ultraviolet light. These pigments are often blue, purple or pink. Coral colonies have many shapes. Some basic shapes—branching, mounding, and plate— may occur at different locations on the reef. Here are three examples: On the reef crest, where light penetration and water movement are greatest, the large, tan elkhorn coral predominates. Elkhorn coral grows rapidly—up to 15 cm (six inches) a year. Because of its exposed location, elkhorn coral is frequently damaged by storm waves. However, it is one of the few coral species known that can regenerate a new colony from a broken branch. On the reef front, massive corals like the mound-forming brain and star corals are found. These corals have a relatively small surface area exposed to light (compared to branching coral) and so depend less on symbiotic algae and rely more on the zooplankton-gathering of their large individual polyps. Mound-forming corals grow much more slowly than branching ones, but they are significant builders of the coral reef platform. Because the large polyps of these species make a big target for fishes that pick off coral tentacles, the polyps remain closed during the day and open only in the dark, when many of their prey—zooplankton—come out. At the base of the reef front, an area of decreased light penetration, the pale white plate coral grows, spreading out flat to maximize exposure to remaining light. DIET Plankton and debris are captured by the tentacles and ingested. Zooxanthellae provide glucose, glycerol and amino acids. PREDATORS Most animals avoid corals because of their stinging cells, though a few fish such as parrotfish and triggerfish and some invertebrate species feed on coral tissue. Sea urchins and nudibranchs also sometimes feed on coral tissue and the crown of thorns sea star is a notorious coral predator. REPRODUCTION AND DEVELOPMENT Corals reproduce both sexually and asexually. During sexual reproduction, a larval stage develops and eventually settles out on a suitable substrate. During asexual reproduction, an existing colony develops by the addition and growth of new buds, all clones of the original. MORTALITY/LONGEVITY Little is known about the lifespan of corals. Generally, coral colonies may live for several decades to centuries. CONSERVATION STATUS Pollution and sediment runoff, indiscriminate collecting of the skeletons for ornaments or jewelry, and destructive fishing practices have degraded reefs around the world. Oceanic August 2010 23 temperature increases are thought to be responsible for a phenomenon known as bleaching, caused by the death or discharge of the symbiotic algae. Rising water levels can affect the growth of corals by causing them to receive less sunlight. Also, oceans are becoming more acidic as higher amounts of carbon dioxide dissolve in the water. Increasing acidity reduces corals’ ability to construct their calcium carbonate skeletons. TO NOTICE Use a map to show location of coral reefs. Use schematic diagram to show the structure of a coral. Show photos of zooxanthellae and zooplankton. Show a photo of a live polyp with tentacles visible. Compare and contrast the various stony coral shapes. Look carefully at the structure of the struts, called septa, which divide each coral cup. The septa of each species of coral have a particular pattern, which is used for classification. Distinguish between branching, mounding, and plate corals. Look at pages describing individual specimens for more “To Notice.” SPECIMEN DETAILS Acropora sp. (Acroporidae) such as, Staghorn, Elkhorn, and other Acropora Coral Distribution: Indo-Pacific, Caribbean. Habitat: Shallow reef environments with bright light and relatively strong currents. Often dominate shallow parts of the reef, especially the surf zone. Appearance: Growth forms extremely variable: slender branched fingers, broad antlers, table-like plates are common. Among the most colorful of reef-building corals; may be cream, yellow, blue, green, purple, pink, even fluorescent. Characterized by light –colored polyps at the tips of branches where budding and growth take place, fueled by the energy produced by zooxanthellae in lower parts of the branch that give it color. Diet: Feed on microplankton, mostly at night; significant nutrition provided by photosynthetic zooxanthellae. Reproduction and Development: Most Acropora species are broadcasters, a few are brooders; also readily reproduce asexually by budding and fragmentation. Fast growing. Remarks: Acropora spp. are particularly susceptible to bleaching when stressed by pollution, warm water temperatures, or excessive sediment or nutrient runoff. The most numerous and widespread genus of the stony corals (Order Scleractinia). A major contributor to reef structures worldwilde. The crown-of –thorns sea star (Acanthaster planci) is a major staghorn predator. 24 DRAFT August 2010 TO NOTICE Note the many indentations on the staghorn coral. Each one is the cup-like skeleton built by an individual coral, called a polyp. The polyp lives within the cup, either extending its tentacles to feed or retracting into the cup for protection. Brain Coral Leptoria phrygia (specimen) Distribution: Northern Australia and Coral Sea to Solomon Islands. Habitat: Commonly encountered on reef slopes but generally absent in areas of turbid water; also found in shallow subtidal areas. Appearance: Colonies are often mound-like or form upright columns with a very lumpy or lobular surface. The narrow valleys are the same width as the walls. The walls and valleys are very sinuous and uniform in width and height. These are usually colored differently: dark green, cream, or brown. Brain Coral Lobophyllia sp. (photo) Distribution: Red Sea through the Indo-Pacific to southern Japan. Habitat: Coral reefs. Appearance: These corals get their common name from the grooves and channels on their surfaces that look like the folds of the human brain. Colonies can grow 6 or more feet (1.8 m) high. Diet: Nutrients provided by algae growing in their tissues and by zooplankton. Conservation Status: Coral reefs around the world are in danger. Silt (fine soil) smothers coral when it washes off the land from farm fields, roads, and building sites. More towns and resorts near shore mean more sewage, oil, and chemicals in the water. Remarks: While staghorn corals grow rapidly to gain new territory, slow-growing brain corals rely on brawn. The hold their ground by being solid and strong enough to withstand the storms that pound more delicate corals to rubble. There’s more than one kind of “brain coral”—several species from two different families of corals share the name—but all help build coral reefs. Mushroom Coral Fungia sp. (Fungiidae) Distribution: Indo-Pacific from the Red Sea and east Africa, west to Hawaii in tropical and subtropical latitudes. Habitat: Among other coral, rubble, or on sand. Appearance and Behavior: The typical inverted cap and gilled mushroom-like appearance gives these corals their common name. The structure is home to a single polyp. Mushroom coral can be up to 28 cm in diameter and their form may be circular or elongate. This coral has short, tapering tentacles and a very large mouth opening. Many septa stretch from the central mouth to sides of the polyp. They are able to produce mucus that damages tissues of other corals and so prevents overgrowth. The mucus also facilitates food capture. August 2010 25 These animals can inflate themselves to remove sediments, right themselves if turned over, and move about slowly by means of cilia. Diet: They derive some nutrition from photosynthetic algae. Fungia corals have been observed eating jellyfish, which may be a primary food source for some and a good “fit” for their large mouths. Reproduction and Development: Sexual or asexual reproduction. In either mode, a vaseshaped polyp gradually grows into a flattened disc. The polyp becomes attached to the substrate by a stalk, which later dissolves. A scar on the underside of the adult skeleton marks the position of the stalk. Mortality/Longevity: Life span of some long-lived species is estimated to be 24-46 years. Conservation Status: All corals are threatened, but Fungia more than some as it is valued in both the live and dead coral trade, where it is used for jewelry and other ornaments. Remarks: Rather than forming colonies like most corals, Fungia corals are usually solitary and free-living. Because they are unattached, Fungia can be easily moved by waves, and so are most often found in protected places, often at depths where wave action is reduced. TO NOTICE Mention that the mushroom coral is unique because it is made by a single polyp. The prominent slit in the middle is the location of the mouth. The tentacles of the living animal extend from or retract into the grooves that radiate from it. Notice how it could be large enough to ingest a jellyfish. Also, point out that the adult mushroom coral, unlike most other corals, is not firmly attached to the substrate. (On the underside, look for the area where the stalk that originally attached it to the substrate was located.) Show photo of a live mushroom coral. Pocillopora sp. Cauliflower Coral, for example Distribution: Indo-Pacific, including Hawaii and the Red Sea. Habitat: Exposed shorelines and the surge zone of reef slopes. Appearance: Colonies have highly variable, branching (arborescent) growth forms, usually with rounded or flattened branches, which may be fine or thick. They have a characteristic bumpy, wart-like texture. Small polyps, when extended, give this coral a fuzzy, cauliflowerlike appearance. Common colors are brown, green and pink. Diet: Nutrients from symbiotic zooxanthellae. Reproduction and Development: Asexual reproduction by a somewhat unusual method called “polyp bail-out”: intermittently, often in response to stress, a colony will release polyps that settle and form new colonies. Reproduce readily in captivity, including sexually by the release of planula larvae. Remarks: Because they are so widely distributed throughout the Indo-Pacific, one source suggested Pocillopora may be the largest contributor to reef-building in the world. They have sweeper tentacles that intimidate less competitive species, though Pocillopora sp. are not as aggressive as species of the genus Euphyllia (Anchor, Hammer, Grape, and Frogspawn Corals). 26 DRAFT August 2010 Turbinaria Coral Turbinaria reniformis (Dendrophylliidae) Distribution: Indo- Pacific, Red Sea and the Gulf of Aden, the southwest, northwest, and central Indian Ocean, tropical and sub-tropical Australia, southern Japan and the South China Sea, West and Central Pacific. Habitat: Variable, from shallow turbid water to clear reef flats and deeper reef slopes. It is found from 2-15m deep. Appearance: This coral can be yellow, brown, or sometimes green. Turbinaria reniformis may form cup, vase, or spreading scroll-like shapes, depending on light and water conditions. In deeper water this coral can grow as spreading plates in order to enable the polyps to take advantage of the waning sunlight. The difference is so striking between the convoluted forms and the plate forms that they seem to be different species. In fact, if a convoluted form is transferred to deeper water, it will slowly flatten its shape. Diet: Many members of this family lack zooxanthellae and are not reef builders. This genus is an exception. Also uses other food sources. Reproduction and Development: Unlike most stony corals which spawn in summer, Turbinaria spawns in the autumn in falling sea temperatures. Also, unlike most corals which are hermaphroditic, Turbinaria has separate male and female sexes and probably releases gametes for external fertilization. Conservation Status: Although Turbinaria reniformis is still relatively widespread and common in parts of its range, evidence of an overall global decline in coral habitat is an indication that this species is almost certainly declining. It is listed as Vulnerable on the IUCN Red List and in Appendix II of CITES, which makes it an offense to trade. It also falls within several Marine Protected Areas. Remarks: When irritated, it can produce large amounts of clear mucus which can damage other corals. August 2010 27 MOLLUSKS: GASTROPODS Cone Snail SPECIMENS cone snail shell GENERAL INFORAMTION CLASSIFICATION Phylum Mollusca, Class Gastropoda DISTRIBUTION Generally found in temperate to tropical oceans. Most species found in Indo-Pacific. Also found in Australia, Japan, west Africa, California, Florida-Caribbean and Pacific-Panama area. HABITAT Most cones are found in shallow reef areas hiding in the sand, under coral shelves or in piles of rocky rubble. Some live among mangroves. APPEARANCE AND BEHAVIOR The size of cone snails varies from 1.3 cm to 21.6 cm. Cone snails have heavy, smooth shells that are narrow at one end and wide at the other. All have spires of varying heights at the wide end. The shell’s aperture is long and narrow and does not have an operculum. The foot is strong and may be colorful. The siphon may also be colorful. The head has two tentacles, each with an eye halfway down. Shell colors and patterns vary. Most have patterns of black, brown, orange or yellow over a light background. This snail’s unique feature is a “harpoon” that is a single, specialized radula tooth equipped with a spear-like barbed tip. The cone snail detects the presence of its prey using chemosensors in its siphon and, when close enough, extends its proboscis (which also acts as a lure) and fires its hollow harpoon-like tooth containing venom into the prey. The harpoons are stored in the radula sac and moved into the proboscis one at a time as needed. They then become attached to a salivary gland, which has been modified to produce venom before the harpoon is fired. The barbed tooth has a groove through which the snail injects the neurotoxic peptide venom (conotoxin) into its victim. This immobilizes the prey and enables the cone snail to wind it into its mouth via an attached filament. DIET Cones are carnivorous. They are classified as fish eaters, mollusk eaters, or worm eaters. Most cones are nocturnal though some hunt at dusk and dawn. They may hide with only the siphon visible before striking their prey. 28 DRAFT August 2010 REPRODUCTION AND DEVELOPMENT Although not widely studied, most of these snails seem to have separate sexes. Fertilization is internal. Egg capsules are attached to substrate. Two types of hatchlings have been described: veligers (free swimming larvae) and veliconcha (basically baby snails). CONSERVATION STATUS Prized for their shells, cone snails are in danger of being over-harvested by collectors. They are also collected for scientific studies on potential uses of the venoms for medicine. This could result in depleted populations. Some countries have put restrictions on their collection and sale. At present only four species are listed as Vulnerable by IUCN. REMARKS Research on cone snail toxins is an active field and has resulted in a new, highly effective painkiller recently approved by the FDA that, unlike opium-derived medications, has a low risk of addiction and can be much more potent than morphine. Small cone snails pose little danger to humans beyond a beelike sting. However, large cone snails inject enough toxin to be deadly. About 30 human deaths have been attributed to cone snail envenomation. TO NOTICE Notice how this beautiful shell gives no indication of the venom that might be within. Using a photo or diagram, point out where the foot, siphon, and proboscis would be located. Show a photo of a cone snail feeding. Compare the cone snails’ use of a “harpoon” to inject venom to the venom delivery system of ray barbs and coral nematocysts. August 2010 29 Tiger Cowrie SPECIMEN tiger cowrie shell Cypraea tigris (Cypraeidae) GENERAL INFORMATION CLASSIFICATION Phylum Mollusca, Class Gastropoda DISTRIBUTION Indo-Pacific, including Hawaii HABITAT Rocky and coral areas APPEARANCE AND BEHAVIOR 10-15 cm in size. In cowries the spire (pointed end) of the shell is overgrown by the last whorl, resulting in a rounded domed shape. The shell may be white or golden brown with scattered dark brown or black spots. The shell-producing mantle tissue has two special folds that extend outside the shell. These mantle folds keep the shell clean and polished and prevent boring or encrusting organisms from causing damage to the shell surface. The mantle is covered with frilly, branched projections called papillae. The functions of the papillae are not clear. They may provide camouflage for the animal by breaking up the snail’s outline or they may allow absorption of oxygen from the seawater. When disturbed, the mantle retracts, revealing the glossy shell. Cowries, like other snails, have a well-developed head with eyes and tentacles, a mouth on a protractible proboscis (mouth tube), a broad muscular foot for crawling, and a soft body mass containing internal organs. Cowries are most active at night and conceal themselves during the day. DIET Algae or encrusting invertebrates like sponges and bryozoans. It uses its file-like radula to scrape food from rock and reef. REPRODUCTION AND DEVELOPMENT Sexes are separate and fertilization is internal. The female lays a cluster of white, parchment-like capsules containing the developing snail embryos. The female broods these capsules, protecting them by covering them with her foot, until the swimming larvae hatch and enter the plankton where they drift and develop. CONSERVATION STATUS: Most of the species are still relatively common, but a few are becoming rare. 30 DRAFT August 2010 REMARKS The glossy shells have been used for centuries as ornaments, money and religious symbols. Today they rank high with shell collectors. TO NOTICE Notice the smoothness of the shell. Locate where the foot and body mass would be. Compare the appearance of this bare shell to a cowrie covered with a mantle (in a photo). Compare this shell to the other mollusk shells on the cart. August 2010 31 Murex SPECIMENS Pink-mouthed murex Murex erythrostomus unidentified murex GENERAL INFORMATION CLASSIFICATION Phylum Mollusca, Class Gastropoda DISTRIBUTION: The Muricidae family is found worldwide. Most are tropical, but some inhabit colder water, such as the species known to decimate oyster beds. The U.S. Atlantic coast and Gulf of Mexico have numerous species. HABITAT Most murex species live in the intertidal or shallow subtidal zone, among rocks and corals and on sandy mudflats. APPEARANCE AND BEHAVIOR Murex snails are noted for their spectacular, sometimes bizarre ornamentation, which most likely protects the animals from predation. Much of what is known about the working of the gastropod radula has been learned from studies of this family of snails. Typically a murex mounts its prey and works its way through its victim’s shell by alternately using its radula to mechanically scrape away the shell and then using secretions from an accessory boring organ to chemically soften the shell, making it more susceptible to mechanical wear from the radula. DIET Murex species are typically active carnivores, feeding on other snails, barnacles, oysters, mussels, chitons, and other invertebrates. The cart species, the pink-mouthed murex, preys upon large clams in the extreme low-tide level. REPRODUCTION AND DEVELOPMENT Sexes are separate and fertilization is internal. Most murex snails spend their larval stages within an egg capsule, ultimately emerging as tiny snails. CONSERVATION STATUS Most species are plentiful, but a few that are especially desirable to collectors are increasingly scarce. 32 DRAFT August 2010 REMARKS Murex snails were used as a source of dye by the Phoenicians. The murex snails secrete a yellowish fluid which, when boiled and treated, makes a permanent purple dye. Wool and silk dyed with this Royal Tyrian purple brought very high prices. Many new towns were settled in the western Mediterranean by Phoenicians seeking fresh beds of the shells. Greeks and Romans also made use of the dye. During Roman times only Senators and Emperors were allowed to wear purple cloth. After the fall of the Roman Empire the dye was used by the Christian Church and gave rise to the official color of the Cardinals. The dye is also used in the Jewish religion. TO NOTICE Notice the spines covering the shell that discourage predators. Note the small worms on the shell-- may have settled on the shell when alive or dead. August 2010 33 Triton’s Trumpet SPECIMEN Triton’s Trumpet Charonia tritonis (Cymatiidae) GENERAL INFORMATION CLASSIFICATION Phylum Mollusca, Class Gastropoda Its name refers to Triton, the ancient Mediterranean God of the Sea. DISTRIBUTION Throughout the Indo-Pacific, in the Red Sea, along the tropical coast of Africa (Mozambique), and in southern Japan. HABITAT In tropical waters to the depth of 3 – 40 m. APPEARANCE AND BEHAVIOR This is one of the largest and best known tropical gastropods. Like other snails, the Triton’s trumpet has a well-developed head with eyes and tentacles, a mouth on a protractible proboscis (mouth tube), a broad muscular foot for crawling, and a soft body mass containing the internal organs, which is protected by the shell. It may exceed 50 cm in length (almost 20 inches). DIET This species feeds on many different echinoderms, but most notably the crown of thorns sea star, which is a significant coral predator. After locating its prey, the trumpet snail immobilizes the sea star with an injection of paralytic salivary juices, then bores through the sea star’s mesh-like skeleton with sturdy radular teeth to reach the soft tissue inside. REPRODUCTION AND DEVELOPMENT Sexes are separate in the trumpet snails and fertilization is internal. The female lays a cluster of white, club-shaped capsules containing the developing snail embryos. The young hatch from the capsules as swimming larvae and enter the plankton to drift in the open water. CONSERVATION STATUS Because it is predatory on the crown of thorns, this species is protected by law in some countries, including Australia, Fiji, and the Seychelles. REMARKS Traditional use includes chipping a small hole near the end of the spire and blowing into it as one would a trumpet. TO NOTICE Using a drawing/photo of a Triton’s trumpet, point out where the eyes, mouth and foot would be located. Show a photo of Triton’s trumpet consuming a crown of thorns sea star. 34 DRAFT August 2010 Compare to other gastropods on the cart such as the murex, cowrie, and cone snail.. August 2010 35 MOLLUSKS: BIVALVES Tridacna Clam SPECIMEN Tridacna clam GENERAL INFORMATION CLASSIFICATION Phylum Mollusca, Class Bivalvia DISTRIBUTION Nine species of Tridacna clams are known and are distributed over the entire Indo-Pacific. HABITAT On coral reefs from near the surface to depths of 30 m. APPEARANCE AND BEHAVIOR Because of their symbiotic zooxanthellae, all Tridacna species grow rapidly. The giant clam, Tridacna gigas, is the largest of all known clams. Tridacna derasa is the second largest. Tridacna gigas can grow to sizes well over three feet and weight 450 pounds. T. derasa can grow to about two feet. Tridacna clams are known for the iridescent pigments in their large mantles. The mantle protrudes from the shell and exposes the photosynthetic zooxanthellae to sunlight. The pigments in the mantle probably reduce light intensity to protect zooxanthellae from overexposure to UV radiation. The clam has two siphons: one is fringed with tentacles for the intake of water to obtain food and oxygen; the other is tube-like and is for the discharge of large volumes of water if the shell closes rapidly. DIET Like other clams, Tridacna has gills that are used to filter planktonic bits from the water as well as carry out gas exchange. Also, these clams, like corals, cultivate symbiotic unicellular algae in their tissues. The algae, called zooxanthellae, produce oxygen and food for the clam. In turn, the clam provides protection and access to light for the zooxanthellae. PREDATORS The mantles of young Tridacna clams are preyed upon by mantis and cleaner shrimps, various snails, crabs, wrasses, triggerfishes, and angelfishes. As the clam grows, its size, strong attachment with byssal threads, and its thick shell are deterrents to most predators except man. REPRODUCTION AND DEVELOPMENT 36 Tridacnas are broadcast spawners, releasing sperm and eggs into the open water in great numbers. Fertilized eggs develop into planktonic larvae that settle and attach to the substrate with byssal threads. Byssal threads become less necessary as increasing weight holds the animal in place. DRAFT August 2010 MORTALITY/LONGEVITY The Tridacna gigas is considered to be very long-lived. One resource suggests 100-year lifespan, another 200 years! CONSERVATION STATUS The giant clam is declining in numbers, and is extinct in many parts of its former range. In Southeast Asia and the Pacific islands, the flesh is considered a delicacy. In China, the adductor muscle is believed to be an aphrodisiac and sells for large sums. Recently, commercial propagation shows some promise of success. REMARKS Giant clams have sometimes been called “killer clams” with stories of humans caught and drowned by sinister attacks on arms and legs. Fortunately for divers, these tall tales are untrue. The most common injury associated with giant clams are hernias, back strains, or broken toes—self-inflicted by people trying to lift these huge animals from the water! TO NOTICE The unpolished area in the middle of the shell indicates where the animal was. Note the tooth and socket articulation of the shell valve. The brownish material above the articulation point is the remains of connective tissue that held the living shell together. Yellowish circles mark attachment site of adductor muscle, used to close the shell. (Tridacna can close shells quite rapidly when mantle is attacked or eyespots on mantle edges sense predators.) Wavy lines are not annual rings. Wider space between rings indicates a period of rapid growth when conditions were optimal. Heavy ridges indicate times of slower growth when the animal was under stress. August 2010 37 MOLLUSKS: CEPHALOPODS Cuttlefish SPECIMENS Cuttlefish bones GENERAL INFORMATION CLASSIFICATION Phylum Mollusca, Class Cephalopoda The cuttlefish is a cephalopod along with the squid, octopus, and nautilus. DISTRIBUTION Indo-Pacific, Europe, Africa. HABITAT Shallow, tropical or temperate coastal waters APPEARANCE AND BEHAVIOR Cuttlefish may be 2 – 3 cm to 1 m in length. The cuttlefish has a head with eyes and other sensory organs, a sac-like body mass that encloses internal organs, a gill chamber, and 10 limbs. The cuttlefish has three hearts and copper-based blood. The brain is ring-like and the esophagus goes straight through the brain. All 10 limbs extend from the head. Eight of the limbs are arms covered with suckers and two are tentacles with suckers only at the tip. The arms are always visible, but the tentacles, are usually retracted out of sight into special pouches in the head. The mouth, located between the arms, has a parrot-like beak and a radula used to tear and rasp their food. The cuttlefish has well-developed eyes with a lens. They see well in low light. The pupils of their eyes are shaped like a “w.” Cuttles locate their prey visually The internal shell, called the cuttlebone is located just under the mantle and extends along the dorsal side of the body. It is many chambered, light, and calcareous. The chambers of the shell contain gas that compensates for the weight of the animal’s tissues, keeping the cuttlefish neutrally buoyant so that it neither sinks or floats and can move freely in the water. Cuttles use fins for fine movement and jetting for gross movement. In order to jet, water is sucked in through the front of the mantle and expelled through the funnel, which can move and control the angle of spray and thereby the direction of travel. Chromatophores in the skin are neurobiologically controlled. They produce five colors-yellow, orange, red, brown, and black. Leucophores are deeper in the skin and produce white color. Iridophores are responsible for iridescence. Cuttlefish can also change their skin texture. 38 DRAFT August 2010 DIET Small mollusks, crabs, shrimp, and fish. When hunting for food, cuttlefish may wave their eight arms. This may be to distract prey or for triangulation. The two long tentacles then shoot out to capture the food. DEFENSIVE STRATEGIES Cuttlefish can observe changes in their environment and then modify their skin color and texture instantly to confuse prey, escape predators, or communicate with other cuttles. Males have been observed to have one side of their body show a dominant display toward other males, while the other side of the body shows a calm display towards a potential mate. They may use their chromatophores to create a “passing cloud” display on their bodies, perhaps as camouflage. They also produce ink that can be used to create a smokescreen or to produce a pseudomorph shape that may serve as a decoy. REPRODUCTION AND DEVELOPMENT Cuttlefish mate face to face. The male uses the third arm on right to transfer sperm packet to female’s buccal area. Sometimes “sneaker” males will spray water to flush another male’s sperm out of the female and leave his own. The female lays 50 – 100 eggs in a clutch. They inflate after they are laid. The female places them in a specific location and then wraps a sticky substance around them. She may come by and fan them from time to time. Ink is incorporated into the eggs for camouflage. As the eggs develop, they become more transparent. Babies are called hatchlings. MORTALITY/LONGEVITY Cuttles live for about a year. All go through senescence. REMARKS Cuttlefish are intelligent and have been able to learn to navigate a simple maze. Cephalopod intelligence is a topic of study for some scientists such as Jean Boal, an animal behaviorist, because cephalopods have such large brains compared to their relatives the clams and snails. Boal says that if we can figure out what they are using their intelligence for, that would tell us what the factors are in the environment that created the need for intelligence and that can shed some light on our own intelligence. Cuttlefish are also interesting because they only live one year and scientists can use them to study how the ability of an organism to learn changes as it ages. TO NOTICE Notice the shape, size, weight, and porous nature of the cuttlebone. Cuttlebones are commonly used as a calcium-rich dietary supplement for caged birds, hermit crabs, snails and turtles. Compare the cuttlebone to the hard parts of other cephalopod cart specimens: the beak of the octopus and the shell of the nautilus. Compare the photos of cuttlefish, octopus, and nautilus. August 2010 39 40 DRAFT August 2010 Chambered Nautilus SPECIMEN nautilus shell nautilus shell sliced section GENERAL INFORMATION CLASSIFICATION Phylum Mollusca, Class Cepalopoda. Species: Nautilus pompilius (Nautilidae) The nautilus is a cephalopod along with the cuttlefish, squid and octopus. DISTRIBUTION Found in the tropical Indo-Pacific HABITAT Usually found between 60 and 750 m on the slopes of coral reefs. In the daytime they will be at the lower depths and then rise to shallower waters each evening to feed on prey that also migrate upward. APPEARANCE AND BEHAVIOR The nautilus is the only cephalopod that has a fully developed shell for protection. A nautilus shell can be 20 to 27 cm across. The surface of a nautilus shell is lined with alternating wavy brown and white lines. The shell is produced by the mantle and is divided into compartments (about four in newly hatched specimens, 30 in mature individuals) and the animal occupies only the outermost “living chamber.” As the nautilus grows, its body moves forward in the enlarged shell and produces a wall to seal off older chambers. The sealed chambers contain argon-nitrogen gas mixture and a liquid saline solution. The chambers are connected by a tube called a sipuncle that gives the nautilus the ability to change the ratio of a liquid to a gas which can modify its buoyancy. The nautilus moves in a see-saw motion using “jet propulsion” by alternately pulling water into the mantle cavity and forcing it out the flexible siphon beneath the tentacles. The direction the nautilus goes is controlled by the way the siphon is pointed. There is a large leathery lid that can be lowered down to cover the shell opening. Normally, however, the lid is raised slightly and the animal’s eyes, tentacles, and siphon protrude. The nautilus has 38 or more tentacles (and even up to 90). Instead of having suckers like the squid and octopus, nautilus tentacles are lined with alternating grooves and ridges that allow them to grip objects. Tentacles pass food into the mouth where a beak-like jaw tears it up and a file-like radula further shreds the food. The nautilus has a very simple eye. The pupil of the nautilus eye is actually a hole and the water the nautilus lives in flows through the eye. Light strikes directly on the retina to create a blurred image. August 2010 41 DIET Migrating to shallow waters each evening, the chambered nautilus is a predator and scavenger. It eats crab, shrimp, small fish, and carrion. Its prey are detected using chemical cues and vision. PREDATORS The nautilus is eaten by the octopus, shark, triggerfish and sea turtle. REPRODUCTION AND DEVELOPMENT The nautilus takes 5-10 years to reach sexual maturity. Males have a modified arm which functions to transfer a sperm packet. Fertilization occurs much later when the eggs are deposited. The female lays several eggs, one at a time. She uses her tentacles to attach each egg to a hard surface where it remains for 9-12 months before emerging as a hatchling. MORTALITY/LONGEVITY The nautilus can live for up to 20 years. CONSERVATION STATUS Collected for the shell trade. It is consumed in its range by humans. Not on IUCN Red List. REMARKS The nautilus is considered by some scientists to be a living fossil since it is virtually unchanged in the last 500 million years. In prehistoric times there were about 10,000 different species of nautilus and they dominated the ancient seas before the rise of the fishes. Now there are only six species. The nautilus eye is interesting because it is an intermediate step in the evolution of the advanced eyes of other cephalopods (octopuses, cuttlefish and squid) and humans. The most primitive eyes are just patches of light sensors on the outside of the skin that can detect light and dark, but not direction. Eyes with light sensors located in a cavity, however, can begin to detect direction. The next stage is the nautilus eye which can detect large shapes but no detail. The final step is the addition of a lens--something that has been done by other cephalopods and humans—to provide clear and detailed vision. TO NOTICE Compare the shell of a nautilus to the only hard part of other cephalopod cart specimens—the octopus beak and the cuttlebone. In the sliced shell, notice where the outermost “living chamber” of the nautilus would be. Notice the connections between the chambers. Since its predators can be triggerfish, octopuses, and sharks, look at these cart specimens and see how they might be able to break or drill through the nautilus shell. Notice the shell’s counter-shading—a form of camouflage coloration which makes it more difficult for predators to see. It is light on the bottom and dark on top. Fish can have countershading, as do our penguins. Point out that this shell can withstand the pressure of the sea at depths of 800 m (over 2,600 feet). 42 DRAFT August 2010 Look at a photo of a live nautilus and see what parts are visible. Look at a photo of the eye of the chambered nautilus and review the description of its structure and how it relates to other types of eyes. Notice the cross-section of the shell is a particularly elegant looking spiral shape—a logarithmic spiral which is a mathematical function first studied by Sir Isaac Newton. The logarithmic spiral has the property of self-similarity: if you make it bigger or smaller, the new curve can be superimposed exactly on the original although you will need to turn it to get it to match. Some other spiral-shelled mollusks, including garden snails, have shells based on the logarithmic spiral, but the nautilus is a particularly striking example. The animal has such a shape because it continues to grow as long as there enough food. The bigger it gets, the more food it can catch, and the faster it grows, so the shell must grow accordingly. August 2010 43 Octopus SPECIMENS octopus beak octopus model GENERAL INFORMATION CLASSIFICATION Phylum Mollusca, Class Cephalopoda DISTRIBUTION Oceans worldwide HABITAT Salt water: open ocean, shallow seas, ocean depths APPEARANCE AND BEHAVIOR Octopuses range in size from 2.5 cm to 9 m (tentacle span). The octopus is a cephalopod—a Greek word that means “head-foot,” but what looks like a large head is actually the baglike body. This body contains the internal organs and is covered with a muscular layer of tissue called the mantle. The octopus does not have a shell. In fact the only hard part is the beak located at the mouth in the center of the arms. This means the octopus can squeeze into small places. The octopus has eight arms with many suckers on each arm. The range of sucker sizes gives the octopus greater dexterity. Suction cups have chemoreceptors that enable them to “taste” what they are touching. Octopuses are probably the most “intelligent” of invertebrates and have a complex nervous system—part of it localized in the brain and part in the system of neurons in the arms. Octopuses monitor their environment using two large and well-developed eyes that can form accurate images and detect slight movements. They are able to learn and perform complex tasks, such as twisting the cap off a jar to reach enclosed food. Captive animals have been known to leave their tank at night to feed in other tanks and then return home before morning. The octopus usually only swims if threatened. It will inflate the mantle cavity with water and then expel it through its funnel causing it to move forward with the arms trailing behind. By moving the funnel, it can change direction. Usually, however, the octopus likes to crawl along rocks, coral and sandy bottoms. It is a solitary dweller in caves or under rocks. Some carry a shell “home” with them. The octopus can change color in less than a second by means of specialized cells such as chromatophores, iridophores and leucophores in the skin. The octopus uses color change as camouflage, but also changes color with shifts in activity and in need to communicate with other octopuses. In addition, with the aid of special muscles, octopuses can alter their skin texture to match the texture of an irregular background. 44 DRAFT August 2010 When threatened, the octopus can also squirt ink into the water before fleeing-—an action that confuses and obscures the vision of predators. DIET Crabs, fish, shellfish Most octopuses hunt at night. It is thought they scout out promising feeding grounds by sight and then extend their sucker-studded arms to explore the area by touch. They then lunge at the prey and grab it with arms and suckers. Octopuses have several tools for penetrating shells. An organ called the salivary papilla is covered with small teeth which can bore through shells. The octopus can also use radula to drill into a shell. The octopus delivers salivary secretions to the drilled hole that further corrode the shell. In addition, saliva weakens the prey and detaches it from its shell. Octopuses use their hard beaks to break up food and then the radula scrapes up the juicy prey. The shells are discarded—creating the “octopus’ garden.” PREDATORS Sharks, large fish such as groupers, and eels REPRODUCTION AND DEVELOPMENT There is no courtship behavior. The male inserts his third arm (hectocotylus) into the female mantle to deposit spermatophores. (Sometimes the arm remains detached in the female.) The male dies shortly after mating. The female may mate several times. The female lays thousands of eggs through her funnel. She hangs them in clusters from the ceiling of her cave. She tends the eggs and aerates them constantly by blowing water over them. At this time she does not eat and dies after the eggs hatch. The juveniles spend weeks in the plankton and then settle on the bottom. MORTALITY/LONGEVITY Octopuses have a relatively short life expectancy although some may live up to five years. Death follows reproduction. CONSERVATION STATUS The octopus is sensitive to water pollution, and its populations in some areas may depend on limiting contaminants. Octopuses are a source of food in Asian and Mediterranean cuisine and therefore subject to possible overfishing. TO NOTICE Notice the size and shape of the chitinous beak. Use a model or photo to point out the location of the beak. Review the way the octopus eats. See the section above entitled Diet. Show the photo of the blue-ringed octopus and tell the story from the section below called In the Field with the Researchers. August 2010 45 Compare to other cephalopod specimens: the nautilus shell and the cuttlefish bone. IN THE FIELD WITH THE RESEARCHERS One of the most lethal venomous tropical sea creatures is the small (about 15 cm) blueringed octopus. It is found in Australia and the Indo-Pacific up to Japan. The bright blue rings become visible when the octopus is alarmed. It feeds on small crabs and shrimp. It has two kinds of venoms: one less toxic for prey, one very toxic for predators. The poison is in the saliva, and it is unclear whether it is expelled into the water or delivered with a bite. The following is a quote from Terry Gosliner, the Academy’s malacologist (studies mollusks) whose specialty is nudibranchs, when he was diving in New Guinea: “It was one of those dives. . . . first I saw a big shark on the south side of Magic Passage, then a stonefish and two scorpionfishes. I began to work up into the shallows, turning over slabs of coral rubble, looking for nudibranchs. . . . All of a sudden I felt a sensation along my bare arm. A five centimeter long blue-ringed octopus (the only lethally toxic octopus) had crawled up from the slab onto my arm. Anti-venom was available at the Madang Hospital about 45 minutes away by boat and car, but I would have had only 20 minutes to get there . . . there would have been no way. I shook my arm and gasped in relief as the octopus fell away. The best part was that I found a new species of nudibranch under that slab.” 46 DRAFT August 2010 ARTHROPODS Hermit Crabs SPECIMENS hermit crabs in a jar model of hermit crab in a shell GENERAL INFORMATION CLASSIFICATION Phylum Arthropoda, Subphylum Crustacea DISTRIBUTION There are over 500 species of hermit crabs worldwide. HABITAT Most hermit crabs live in saltwater at depths ranging from shallow reefs and shorelines to the deep sea. In the tropics, some are terrestrial. Hermit crabs begin their life in the sea, but as they molt, they develop the ability to breathe air. However, they must carry small amounts of water in their shells at all times to keep their abdomens and gills moist. APPEARANCE AND BEHAVIOR: Hermit crabs are different from “true crabs” because they have a reduced and softened abdomen. They protect this vulnerable part of their body by using an empty shell as armor. The hermit crabs’ abdomen curves to fit the shell. Only the cephalothorax area is covered by an exoskeleton. They have five pairs of legs including a pair of claws. One claw is larger than the other and is used for defense and food shredding. The smaller claw is used for eating. The second and third pairs help the crab walk and the last two pairs of hook-like limbs hold the crab in its shell. When a hermit crab outgrows its shell, it must find another. Hermit crabs may even fight with each other over shells. When the hermit crab locates a shell, it carefully checks the inside and outside with its antennae and claws. Then, releasing its anchoring limbs from the old shell, it slips its abdomen out of the old shell and into the new. If the fit is good, it keeps the shell. If not, it transfers back to the old shell. The compound eyes are on movable stalks and can pick up fine movements. They have two long antennae to feel their way and two bent antennules that taste/smell. Three pairs of maxillipeds are appendages used to groom and move food to the mouth. DIET Hermit crabs are omnivores and scavengers. August 2010 47 PREDATORS Larger hermit crabs, box crabs, octopuses, as well as wrasses and other reef fishes with jaws for crushing shelled vertebrates are predators. REPRODUCTION AND DEVELOPMENT After mating, females carry their eggs attached to tiny limbs on their abdomen. The young hatch as larvae and are immediately swept into the plankton. When they have reached the right stage of development, they drop to the seafloor, metamorphose into their final form, and find an empty shell. CONSERVATION Hermit crabs are abundant, but the number of available shells is important to their survival so empty shells should not be collected. REMARKS Some hermit crabs have sea anemones growing on their shells. This symbiotic pairing, called mutualism, provides protection and camouflage for the hermit crab and gives the hitchhiking anemones food scraps from the crab. When disturbed, the anemones aboard for the free ride expel acontia (lengthy sting cells). Hermit crabs have been observed transferring their hitchhikers to a new shell. TO NOTICE Use the hermit crab model to discuss body parts and the concept of shell change. 48 DRAFT August 2010 ECHINODERMS: SEA STARS Sea Stars SPECIMENS Blue Linkia sea star Chocolate Chip sea star GENERAL INFORMATION CLASSIFICATION Phylum Echinodermata, Class Asteroidea DISTRIBUTION 2000 species worldwide HABITAT Sea stars live in all the world’s oceans; a few species inhabit brackish waters. APPEARANCE AND BEHAVIOR The name echinoderm means “spiny-skinned” and refers to the sea star’s possession of calcium-carbonate spines and plates that form an internal skeleton just under the skin. This offers protection. Many also have coloration that provides camouflage. As adults, echinoderms are radially symmetrical with a five-sided body plan surrounding a central disk where the mouth lies. Most have five arms, but species with 10, 20, and even 40 arms exist. Sea stars are famous for their ability to regenerate limbs, and in some cases, entire bodies. Some require the central body to be intact to regenerate, but a few species (like the blue linkia) can grow an entirely new sea star from a portion of a severed limb. The phylum is also characterized by a water vascular system with canals that end in tube feet. Water enters the system through a madreporite, which maintains water pressure that, along with muscular contractions, works to move the tube feet, which may be adapted for respiration, feeding, movement, or sensory perception. The tube feet also enable the sea stars to hold on tightly to the substrate. DIET Sea stars can be carnivores, omnivores, scavengers, and herbivores. Feeding strategies are varied. Some extrude their stomachs between the shells of bivalve mollusks and secrete enzymes that digest the prey’s soft tissues. REPRODUCTION AND DEVELOPMENT Reproduction is predominately sexual. Larvae are free-swimming and bilaterally symmetrical, a part of the plankton until, after a series of stages, they metamorphose into adult forms. August 2010 49 MORTALITY The average life span of sea stars in the wild is up to 35 years. REMARKS The early embryonic development of echinoderms, chordates, and two smaller phyla is so distinct from that of all other animal phyla that these four phyla are presumed to have evolved separately from a common ancestor. Echinoderms, then, are thought to be among our closest invertebrate relatives. Often has a symbiotic relationship with other animals: A commensal relationship with a shrimp, Periclimenes soror, which are often the same color as the sea star. A parasitic relationship with a sea snail, Thyca crystalline, which may be found on the oral side of the animal partially imbedded in the ambulacral grooves. TO NOTICE Point out the radial symmetry. Also, show the location of tube feet and mouth. Does it look like the sea star ever regenerated a limb? Compare to the test of a sea urchin. Compare the sea star to a photo of the crown of thorns. Show photo of Triton’s trumpet consuming a crown of thorns. Show an actual Triton’s trumpet. SPECIMEN DETAIL Blue Linkia Sea Star Linckia laevigata (Ophidiasteridae) Distribution: Indo-Pacific Habitat: Coral rubble or among seagrasses in shallow lagoons and to 60 m depth. Appearance: Overall arm radius to 40 cm. Color bright blue overall, but olive-brown, pink and yellow variants exist. Has long, cylindrical, smooth arms. Diet: Scavenger. Also consumes algae and microbes. Predators: Pufferfishes and tritons are known to feed on blue linkias and harlequin shrimp nibble on the ends of their rays. Reproduction and Development: Unlike most sea stars that can regenerate missing parts only if at least part of the central disk remains, linkias are able to regenerate into a complete sea star from a single ray. Initially four minute arms bud from the end of the lone ray; this form is called a comet, as it resembles a shooting star. Chocolate Chip Sea Star Protoreaster nodosus (Oreasteridae) Distribution: Red Sea, Indian and western Pacific oceans Habitat: Shallow sand and seagrass beds, typically in sheltered locations from 1 to 30 m. Appearance: Diameter to 30 cm. Body color is variable—may be beige, brown, orange, red, green, or blue. Horn-shaped nodules are blue, dark green, brown, or black, sometimes surrounded by milk chocolate-colored margins. 50 DRAFT August 2010 Diet: Sponges, clams, snails, other invertebrates; also opportunistic carrion feeders. Reproduction and Development: Eggs and sperm are stored in the rays and released simultaneously. Fertilization is external. Larvae are bilaterally symmetrical and planktonic. Larvae settle and transform to sea stars. Conservation Status: Common but threatened in some areas, such as Singapore. They are overharvested for the shell trade because of their appearance; however, coloration fades upon death. August 2010 51 ECHINODERMS: URCHINS Sea Urchins SPECIMEN sea urchin test GENERAL INFORMATION CLASSIFICATION Phylum Echinodermata, Class Echinoidea DISTRIBUTION Sea urchins are found in tropical and temperate waters worldwide. HABITAT Intertidal reefs and shallow tropical and temperate waters. APPEARANCE AND BEHAVIOR Like sea stars, sea urchins have radial symmetry. The organism has an axis, or a central point of rotation. It has no left or right sides, but has a top and a bottom (dorsal and ventral surface) only. Also, like sea stars, urchins move by means of hundreds of tiny, tube feet: and have a hard outer shell (“test”) with external spines which also aid in locomotion. The spines fall off when they die. DIET They feed mostly on algae using five tooth-like plates, called Aristotle’s lantern that surround the mouth which is located on in the center of the ventral side. REPRODUCTION AND DEVELOPMENT: Reproduction is predominately sexual. Larvae are free-swimming and bilaterally symmetrical, a part of the plankton until, after a series of stages, they metamorphose into adult forms. REMARKS Sea urchins are harvested and served as a delicacy. TO NOTICE Notice the radial symmetry, location of spine attachment, and location of mouth. Compare to another echinoderm such as the blue linkia sea star. Show photos of tropical urchins to look for in the Academy such as the long-spined sea urchin, tuxedo urchin, and fire urchin. 52 DRAFT August 2010 SPECIMEN DETAIL Pencil Sea Urchin Eucidaris tribuloides (Cidaridae) Distribution: Caribbean, Bahamas, Florida Habitat: Coral reef in small crevices, in turtle grass beds, or under rocks and rubble in back reef lagoon areas, usually found at less than 50 m. Appearance: Brown body with thick spines in all directions Diet: Omnivore that eats algae and small invertebrates, such as sea squirts and sponges. It feeds nocturnally. Reproduction and Development: Sexual reproduction: eggs and sperm are synchronously shed into the water column where fertilized eggs develop into free-living larvae that, after several stages, settle out of the plankton. Mortality/Longevity: Lifespan up to five years Remarks: Pencil sea urchins belong to a primitive sea urchin order, the Cidaroids, the only kind of sea urchin to survive the Permian extinction some 245 million years ago. All modern sea urchins descend from this group. The spines of pencil urchins, unlike other urchin groups, are not covered with epidermis. They are, however, often covered with algae and epizoans that provide excellent camouflage. Spines are also covered with barbs that can inflict serious pain to a predator. They seek shelter in rocky crevices by day, using the thick spines to hold a protected position. Look for this urchin in the Caribbean tank. August 2010 53 VERTEBRATES: CARTILAGINOUS FISHES Rays SPECIMENS ray barbs ray model GENERAL INFORMATION CLASSIFICATION Phylum Chordata, Subphylum Vertebrata, Class Elasmobranchii Rays belong to a group that also includes skates and sawfishes. DISTRIBUTION Found in tropical and temperate seas around the world. HABITAT Most species are marine, but many can penetrate estuarine waterways and even freshwater areas. One family of river stingrays is exclusively freshwater. Many rays live in shallow, coastal waters. Some, such as the pelagic stingray, live in open water. APPEARANCE AND BEHAVIOR Rays have skeletons made of cartilage. Their flattened bodies have large pectoral fins joined to their head and trunk with the tail trailing behind. When rays move, most swim by undulating their bodies like a wave; others flap their fins like wings. Gills are on the underside of the ray. Clean water flows into the gill chamber through a circular opening just behind the eye, called a spiracle. (If water entered through the gills themselves, the gills might become clogged with sea bed mud.) Water exits through the gills. The five gill slits are visible on the underside of the ray. The snout is sensitive as it noses in mud for food. The nostril is an opening to an olfactory organ and is guarded by a flap. Rays hunt mostly by scent. The horny mouth on the underside is adapted for grasping shellfish, worms, fishes, and other bottom loving creatures. These creatures are ground up with flat jaw teeth. Rays have large, movable eyes and good eyesight. Many rays have a venomous spine (also known as a barb or stinger), but some do not. (The Academy’s bowmouth guitarfish is classified as a ray, but does not have a venomous sting.) In those that have the spine, it can be located in several positions. In the family Dasyiatidae (like the Academy’s honeycomb stingrays) the spine is relatively far back on the tail and can deliver a powerful blow. In the family Myliobatidae (like the Javanese cownose ray) the spine is at the base of the tail and is a less effective weapon. The spine is actually a modified dermal denticle. (The ray’s skin is partially covered with dermal denticles—“skin teeth” that contain dentine like normal teeth.) The stinger can have serrated edges and a sharp point. Some rays have even two or three stingers. The stinger can 54 DRAFT August 2010 be 5 to 16 inches long (12 – 40 cm). The rays’ venom glands are located in paired grooves on the underside of the spine. Rays use the venom mainly as a defense against larger predators. When threatened, a ray can lash its tail back and forth or arch it over its head, slashing and stabbing its stinger into the enemy. A stingray has even been seen making a threat display with the tail raised when a shark came too close. If a ray loses its tail spine, it immediately begins to grow a new one. Stingrays shed and re-grow their spines on a regular basis regardless of whether they use them. The stingray has electrical sensors called “ampullae of Lorenzini.” Located around the stingray’s mouth, these organs sense the natural electrical charges of potential prey. Rays often hide in the sand with only their eyes slightly exposed. The back of a ray may be camouflaged, while the underside need not be. To uncover buried prey, rays force jet streams of water through their mouths or use the undersurface of their wing like a giant suction cup to suck buried prey out of their burrows. Some rays visit “cleaning stations” where fish such as bluehead wrasses and Spanish hogfish eat parasites and mucus from the stingrays’ bodies. DIET Worms, fishes, shellfish PREDATORS Sharks, whales, and larger rays REPRODUCTION AND DEVELOPMENT Rays give birth to live young. CONSERVATION STATUS Some rays are fished for food, but are still in ample supply while others are at risk. Habitat degradation can also be a problem. REMARKS Feeding stingrays is a tourist activity in some resorts. However, in rare cases the stings of some rays can be fatal to humans. Other effects include numbness, paralysis, difficulty breathing, and blood poisoning. If going swimming where there are rays, humans should shuffle their feet. Stingray skin is processed into leather that’s strong and durable. At one time craftsmen used this rough leather for sandpaper and samurai warriors wore stingray leather armor. Modern tanning methods have made the leather more pliable so it is in demand for wallets and accessories. The manta ray is the largest living ray with a wingspan exceeding 20 feet. It has lobed “scoops” (adapted from the front parts of the pectoral fins) on the front of the head to channel food into the great mouth. Despite their size, mantas have small teeth and are gentle filter feeders, cruising the upper waters of warm oceans and consuming plankton, small fishes, and shellfish. They can also leap up to 5 feet (1.5 m) from the water. Their name comes from the Spanish word for blanket. There are also electric rays. An example is the Atlantic torpedo ray that lies on the sea floor for much of the time, but when it wants to feed on small fish and shellfish, it swoops in, August 2010 55 wraps its pectoral fins around the victim and delivers shocks of over 200 volts from specialized muscle blocks on either side of its head. TO NOTICE Notice the size and shape of the barb. Note the position of the barb on a model or photo. Notice the various ray body parts on a model or photo: gills, mouth, spiracles, eyes, nose. Compare the anatomy, diet, and other characteristics of the manta ray to the blue-spotted stingray or other rays. SPECIMEN (MODEL) DETAIL Blue-spotted Stingray Dasyatis kuhlii (Dasyatidae) Distribution: Throughout the tropical Indo-west Pacific from the Red Sea to the Philippines, Japan, and south to Australia Habitat: Sandy bottoms near coral and rocky reefs, from intertidal zone to 50 m. It moves onto reef flats and into shallow lagoon waters at high tide. Appearance: Dorsal color is reddish-brown to olive drab with blue spots and smaller black spots; ventral side is white. Tail with black and white bands is about as long as the body and usually has one stinging spine. Disc up to 50 cm wide. Diet: Crabs and shrimp, also small fishes Reproduction and Development: Ovoviviparous (eggs retained in the female’s body); embryos receive nourishment from a yolk sac. Mortality/Longevity: Killer whales are known predators; probably also taken by other marine mammals and sharks. Remarks: The tail can deliver a painful wound, but it usually only stings when it is inadvertently stepped on in turbid waters. It is caught commercially, but its small size makes it of limited value. Manta Ray Manta birostris Distribution: Tropical waters worldwide; sometimes in warm temperate areas. Habitat: Manta rays usually swim at the surface in contrast to other rays that are bottom dwellers. They tend to congregate over high points on coral reefs where currents bring up plankton. Found at a depths of 0-24 m. Appearance and behavior: The manta ray is the largest ray. Wingspan is up to 8 m and weight up to 1.8 metric tons (4000 lb). When feeding, it swims along with its cavernous mouth wide open, beating its huge triangular wings slowly up and down. On either side of the mouth, which is at the front of the head instead of on the underside as in other rays, are two long lobes, called cephalic horns, which funnel plankton into the mouth. These are the origin of the manta’s other name—devil ray. 56 DRAFT August 2010 Diet: Plankton and small fish Reproduction: Ovoviviparous. Despite their size, manta rays can leap from the water, occasionally giving birth to their young as they do so. Remarks: Mantas may be sociable with divers in some sites and have been known to “dance” with them. August 2010 57 Sharks SPECIMENS sandbar shark jaw hammerhead and whale shark models GENERAL INFORMATION CLASSIFICATION Phylum Chordata, Subphylum Vertebrata, Class Elasmobranchii DISTRIBUTION Sharks are found in all the world's oceans. HABITAT Sharks range from the shallow areas near shore to deep, open water. APPEARANCE AND BEHAVIOR The streamlined, torpedo-like form of most sharks contributes to their success as efficient predators of the world's oceans. Shark skeletons are composed of cartilage rather than bone. Lacking a swim bladder, sharks increase buoyancy by means of a large, fatty liver; however, unless a shark swims actively, it will sink to the bottom. Sharks vary in size from the whale shark, which may reach 50 feet, to species considerably less than a foot in length. A shark may have from 6 to 20 rows of teeth, depending on the species. Usually only the first two rows of teeth are used for feeding. The others are replacement teeth that move forward in conveyor-belt fashion when older teeth are broken off. They may replace teeth every few days, thus keeping the functional rows razor sharp. The teeth vary with the species; variations of size and shape are related to diet. Shark teeth are modified scales, with the same basic structure as the denticles that cover the shark's skin and give it a sandpaper texture. DIET Most sharks are carnivorous, though the largest species—the whale shark and the basking shark—feed chiefly on plankton. Most sharks feed on each other or bony fish. A few seem to eat almost anything. A tiger shark was found to have shoes, a license plate, deer antlers, a chicken coop, and even medieval armor inside its body. PREDATORS Adult sharks have few predators except each other, other large bony fishes, sea lions, and man. 58 DRAFT August 2010 REPRODUCTION The young of many sharks hatch from eggs and are born alive. Other sharks lay distinctive egg cases. Fertilization is internal. CONSERVATION STATUS Overfishing has depleted shark populations around the world. As other fish stocks have been depleted, shark meat has gained in popularity in many countries, including the U.S. To satisfy the demand for shark fin soup, prized in Asian countries, fishing crews often catch a shark, cut off its fins, and throw the animal back. REMARKS Most shark species pose little threat to man, either because they are unaggressive or relatively small. However, great white, tiger, bull, oceanic white tip, and hammerhead sharks have been known to attack humans. In the case of the great white, researchers suggest that many attacks on humans are caused by mistaken identity. The shark mistakes its victim for large sea mammals, such as sea lions or seals. Statistics show about 50 shark attacks occur a year, resulting in about five human deaths. CAS scientist John McCosker is a leading contributor to the understanding of sharks. TO NOTICE Explain that the jaw is made from cartilage, not bone. The jaw is only loosely attached to the skull. When a shark bites its prey, the jaws move forward allowing the teeth to be used more efficiently. Point out that the rows of teeth will move forward as replacements are needed. Discuss how the diet, hunting strategies, and other behaviors of the hammerhead (model) and whale shark (model) might differ from the sandbar shark. SPECIMEN DETAILS Sandbar Shark Jaw Carcharhinus plumbeus Distribution: Globally distributed in temperate and tropical waters Habitat: Bottom-dwelling, shallow coastal water species that prefers smooth substrate and avoids coral reefs. Appearance: Averages 2 m (6.5 feet) in length. Has a taller than average dorsal fin; is bluish to brownish gray color. Diet: It is a bottom feeder that eats small fishes, mollusks, and crustaceans. Predators: Juveniles are preyed upon by larger sharks. Adults have few predators, except humans. It is the most common shark species caught in the U.S. Reproduction: A female sandbar shark can become gravid every other year. Litter size varies by region. There can be 6-13 pups. Conservation: It is listed as Near Threatened by the IUCN. Whale Shark Model Rhincodon tipus Distribution: Tropical and temperate waters worldwide. August 2010 59 Habitat: Most often seen in open seas, but comes near coral reefs, also. It is found near the surface but in deep water in winter. Appearance and Behavior: The largest of all fish, the whale shark can grow up to 18 m long and weigh up to 12 metric tons. The pattern of white spots on the whale shark’s back is unique, enabling scientists to identify individuals. Its mouth is 1.5 m wide, but it is a harmless filter feeder. Whale sharks have a large number of tiny teeth that have no function for eating but they could bruise a diver who came in contact with them. These whales are placid and allow divers to hang onto their fins. Diet: Plankton and small fish. To obtain the huge amount of food it needs, it sucks water into its mouth and pumps it over its gills where particles become trapped by bony projections called gill rakers. Water then passes over the gills where gas exchange occurs. Remoras may attach themselves to a whale shark near its mouth and eat what falls out. In return, remoras eat the itchy parasites that live in the shark’s skin. Reproduction: Whale shark eggs hatch inside the mother, and she gives birth to live young. The eggs are 40 times larger than chicken eggs. Mortality/Longevity: Some scientists think they may live over 100 years. Conservation Status: They are killed for their meat and fins although they are legally protected in some countries. Remarks: Every year around April, whale sharks migrate to Ningaloo Reef off northwestern Australia for a plankton feast. The plankton explosion results from a simultaneous mass spawning of the reef’s corals, possibly triggered by a full moon. Hammerhead Shark Model Sphyrna sp. Distribution: Tropical and warm temperate waters worldwide. Habitat: Can be found in deeper water, but also go up to shallow areas. They are found at depths of 0-500 m. Appearance and Behavior: The largest hammerheads are more than 6 m in length. All have a flattened, T-shaped head. The eyes are at the ends of its head so as it swims it turns its head from side to side. The nostrils are near the ends of the head. Its sense of smell is thought to be ten times better than that of other sharks. They also find prey by detecting electrical signals that the prey sends out as it moves. Some hammerhead sharks hunt at night in packs of 100 or more. Others may hunt individually at night, but swim together by day. The shape of its head may act like a wing, giving the shark lift as it swims. Diet: Fish, other sharks, octopuses, crustaceans, and stingrays. Hammerheads are not deterred by the ray’s venomous spines. Some have been found with 50 spines in their mouth and throat. Reproduction: They give birth to live young in shallow bays and estuaries where the skin of the young darkens to give protection against sunlight. 60 DRAFT August 2010 Conservation Status: Almost all the hammerheads are at risk. The fins are among the most expensive shark fins when sold. August 2010 61 VERTEBRATES: BONY FISHES Parrotfishes SPECIMENS parrotfish lower jaw GENERAL INFORMATION CLASSIFICATION Phylum Chordata, Subphylum Vertebrata, Class Actinopterygii, Order Perciformes, Family Labridae, Scaridae sp. DISTRIBUTION Parrotfishes are abundant in and around the tropical reefs of all the world’s oceans. There are about 80 identified species. APPEARANCE AND BEHAVIOR Parrotfishes range in size from 30 to 180 cm. They are recognized by their parrot-like beak of fused teeth, a bluntly-rounded head, large scales, and brilliant colors. They have a single dorsal fin and swim with lazy rowing motions of their pectoral fins. Parrotfishes travel alone or in mixed groups close to the reef. They are diurnal. At night they seek shelter among the rocks and coral and some parrotfish even make pajamas for themselves. Every night, certain species of parrotfishes envelope themselves in a transparent cocoon made of mucous secreted from an organ in their head. Scientists think the cocoon masks their scent, making them harder for nocturnal predators, such as moray eels, to find. DIET Parrotfishes are primarily herbivores that feed on the algae that grow on rock or dead coral surfaces. A few species may also feed in part on living coral. The parrotfish uses its beak for chiseling away at the coral. The coral is then pulverized by a pair of hard, grinding plates in the throat (pharyngeal teeth) in order to get to the algae-filled polyps inside. Much of the sand in the parrotfish’s range is actually the ground-up, undigested coral they excrete. It has been estimated that a large parrotfish may produce as much as a ton of sand a year. REPRODUCTION AND DEVELOPMENT Some male parrotfishes maintain harems of females. If the dominant male dies, one of the females will change gender and color and become the dominant male. MORTALITY/LONGEVITY Their average lifespan in the wild is up to seven years. 62 DRAFT August 2010 CONSERVATION STATUS Their meat is rarely consumed in the United States, but it is a delicacy in many other parts of the world. In Polynesia, it is served raw and was once considered “royal food,” only eaten by the king. TO NOTICE Notice how the jaw with its fused teeth is suited to chiseling coral. Show a photo of a parrotfish. Compare these fused teeth to the teeth of the shark and triggerfish. August 2010 63 Pufferfishes Pufferfishes (Spiny, Smooth, Sharpnose) SPECIMENS porcupinefish porcupinefish spines GENERAL INFORMATION CLASSIFICATION Phylum Chordata, Subphylum Vertebrata, Class Actinopterygii , Order Tetraodontiformes, Family Diodontidae (spiny pufferfishes), and Family Tetraodontidae (smooth pufferfishes, sharpnose pufferfishes) DISTRIBUTION/HABITAT The pufferfishes, also known as blowfishes or balloonfishes, include two families listed above. More than 120 species are found worldwide in tropical and temperate waters, including marine and some freshwater habitats. APPEARANCE Pufferfishes are named for their ability to inflate their body as a defense. When threatened, they swallow water to fill their expandable stomachs. Since their ribs are quite short and do not form a cage around the stomach, the entire body increases in diameter two to three times making the body too big for a predator to handle. In general, pufferfishes are slow swimmers, but highly maneuverable (especially when not puffed up). Many pufferfishes also have chemical defenses. Their skin produces a potent toxin that may deter predators. The toxin is twelve hundred times more poisonous than cyanide and has no known antidote. Called tetrodotoxin, the poison, which paralyzes its victim to the point of asphyxiation, is produced by bacteria that the fish ingests. Some pufferfishes have wild markings and colors to advertise their toxicity, while others have muted or cryptic coloring to blend in with the environment. Family Diodontidae: Spiny pufferfishes or porcupine fishes have spines that are modified scales on their nearly spherical body. The spines stand erect when the fish inflates. Family Tetraodontidae: Smooth pufferfishes have short, rounded bodies. Their skin lacks scales but may have short, prickly bumps. Within this family are another group called sharpnose pufferfishes or tobies. DIET Pufferfishes eat slow moving or immobile bottom-dwelling reef animals like crabs, snails, and sea urchins. They also eat algae. CONSERVATION STATUS Some species of pufferfish are considered vulnerable due to pollution, habitat loss, and overfishing, but most populations are considered stable. 64 DRAFT August 2010 REMARKS Pufferfish with toxin in their skin are called “fugu” in Japan. While the flesh itself is not poisonous, the fish must be prepared by an expert so that toxins stored in the skin and internal organs do not contaminate the meat making it fatal to the gourmet. Those who have eaten correctly prepared fugu, say it tastes like chicken. An example of how pufferfishes are also important to the ecology of the coral reef involves their relationship to the long-spined sea urchins. When pufferfishes were captured in large numbers for the tourist trade, the number of long-spined sea urchins exploded. These urchins scraped corals to feed on the algae growing on them thus causing the destruction of large coral areas. TO NOTICE Have the visitor feel the spines and discuss their usefulness as a defense. Explain that the spines are actually modified scales that lay flat against the body most of the time. Notice the inflated size of the fish and estimate how big it would be at one-third or one-half that size. SPECIMEN DETAILS Spiny Pufferfish (Porcupinefish) Diodon hystrix (Diodontidae) Distribution: Found worldwide in tropical waters. Habitat: Found in shallow seaward reefs and lagoons. Rests during the day under ledges or plate corals. Commonly seen in caves and holes. Emerges at night to feed. Sometimes hovers high in the water. Appearance: Length to 91 cm, weight to 2.8 kg. Has prominent 5-7 cm quill-like erectable spines over the head and body. Has very large eyes that help locate prey in the dark. Tough skin is scaleless. The teeth are fused together into a single unit creating a strong beak-like mouth capable of cracking the shells of snails, sea urchins, and hermit crabs. Predators: This fish is eaten by large carnivorous fishes including the dolphinfish, wahoo, and sharks. Reproduction and Development: The eggs drift with the current and hatch after five days. Larvae then continue to develop. Juveniles are pelagic until reaching 20 cm in length, after which they become benthic. Conservation Status: The fish is not listed as endangered or vulnerable. Their bodies are sold as tourist novelties in some places. On some Pacific islands in the past the dried skins were used as war helmets. They are collected for aquariums. August 2010 65 Triggerfish SPECIMENS triggerfish skull GENERAL INFORMATION CLASSIFICATION Phylum Chordata, Subphylum Vertebrata, Class Actinopterygii, Order Tetraodontiformes, Family Balistidae DISTRIBUTION Forty species of triggerfishes are found in tropical and subtropical seas throughout the world, but especially in the Indo-Pacific. HABITAT They are mostly found on coral reefs in relatively shallow water. APPEARANCE AND BEHAVIOR Triggerfishes have a highly compressed body and close-fitting scales that provide a flexible armor. They are mobile, but not fast swimmers noted for providing propulsion by the undulations of the second dorsal and the anal fins, with an occasional boost from the pectorals. The caudal fin is mostly used as a rudder. Like their close relatives the surgeonfishes, they have spines on the caudal peduncle used to intimidate potential competitors and others. Their small eyes on top of their head rotate independently. The common name comes from an interaction between the large first dorsal spine and the smaller second one behind. When the posterior spine is erect, it locks the strong first spine in place, wedging the fish into a protective space, perhaps a hole or under a rock, where a predator can rarely extract it. When the posterior spine is depressed, the anterior spine folds back easily, like taking a lock off a trigger. DIET Most are solitary diurnal predators that feed on invertebrates such as sea urchins, mollusks, crabs, other crustaceans and corals. The triggerfishes’ sharp teeth capture prey and their flattened teeth crush shells. Various triggerfishes may also eat algae, detritus, sponges, octopuses, and fishes. REPRODUCTION AND DEVELOPMENT The sexes are separate and fertilization is external. The female lays demersal (deposited near the bottom of a body of water) eggs in a nest. Females or males may guard the nest depending on the species. Some triggerfish can be very aggressive when guarding their eggs. CONSERVATION STATUS Some triggerfishes are collected for the aquarium trade. 66 DRAFT August 2010 TO NOTICE Notice that the jaw contains four teeth on either side while the upper jaw contains an additional set of six plate-like pharyngeal teeth. Show the photos of triggerfishes. Suggest visitors try to spot them in the Main Coral Reef Tank. Discuss how the vivid coloration may be of value on the coral reef. August 2010 67 Seahorses SPECIMENS seahorses GENERAL INFORMATION CLASSIFICATION Phylum Chordata, Subphylum Vertebrata, Class Actinopterygii, Order Syngnathiformes, Family Syngnathidae, Hippocampus sp. Comments apply to all species of the genus DISTRIBUTION Indo-Pacific, Atlantic Ocean, and Mediterranean Sea HABITAT Shallow tropical marine waters APPEARANCE AND BEHAVIOR Seahorses have a long and thin body enclosed in bony rings. They have a tube-like snout with a terminal mouth. Lacking pelvic fins, seahorses locomote with dorsal and pectoral fins and swim slowly in an upright posture. The caudal peduncle has evolved into a prehensile “tail” for grasping plants. Seahorses can be over 16 cm in length. They are often colored brown and may have lighter spots. Like most other syngnathids, seahorses may undergo color changes to blend with their surroundings, to indicate breeding readiness, or to indicate mood or stress. DIET Seahorses suck tiny planktonic prey, especially crustaceans, into their tube-like mouth. They locate prey with binocular vision. DEFENSIVE STRATEGIES Evolutionarily, seahorses have sacrificed streamlining and speed for heavy armor. The bony plates that lie beneath the skin provide protection, but they limit the seahorse’s flexibility and movement Seahorses may change color to camouflage their appearance. REPRODUCTION AND DEVELOPMENT Seahorses dance and sway as they court and bond with their mates. The female then lays her eggs in the male’s brood pouch, where they are incubated and hatched. When the young are expelled, they are capable of swimming. CONSERVATION STATUS Many populations of seahorses are very endangered due to collection as an ingredient in the traditional Asian, especially Chinese, pharmacopeia. Over 95% of the seahorses caught per year are used in traditional Chinese medicines to treat a variety of ailments from impotence and infertility to asthma and skin diseases. The present rate of harvest is unsustainable. Possible remedies that preserve both seahorses and useful medicines may be the synthetic 68 DRAFT August 2010 production of these potions or an increase in farmed seahorse populations. Seahorses are also collected for the souvenir and aquarium trades. Steinhart’s seahorses were reared in captivity as part of a cooperative breeding program between many public aquariums. TO NOTICE The seahorse seems to be a combination of different creatures: the head of a horse, the grasping tail of a monkey, the rotating eyes of a chameleon, and the pouch of a kangaroo. Notice the rigid body enclosed in bony rings. Notice the tube-like mouth used for sucking in planktonic prey. Compare the seahorse to another fish on the cart such as the pufferfish and explain how they are related/classified as bony fish. August 2010 69 Appendix: In the Academy The following pages indicate where to find live animals described in the Specimen Description section of this document. SPONGES Only a few small sponges can be found in CAS because they produce toxins that put demands on the filter system and can discourage coral growth. SOFT CORALS AND GORGONIANS There are a number of soft corals in the coral reef area of the aquarium. The Phillipine Coral Reef tank has several species of gorgonians and other soft corals. The Caribbean tank has several kinds of sea plumes and sea rods and an encrusting gorgonian. In the Reef Partnerships cluster, shrimpfish (swimming head down) use the Pacific gorgonian for protection. (Note that the shrimpfish may also use sea urchin spines for protection.) HARD CORALS Many coral specimens can be found in the Coral Reef section of the Aquarium: in the main tank, in smaller tanks, and in the Seagrass Lagoon. CONE SNAIL The marble cone snail is found in the Venoms Cluster of the Aquarium. COWRIES There are no cowries in the Academy. MUREXES There are no murexes in the Academy TRITON’S TRUMPET The Academy does not have a Triton’s Trumpet TRIDACNA CLAM Look for the clams in the shallow tropical Seagrass Lagoon on the main floor. CUTTLEFISH Cuttlefish are found in the Water Planet. CHAMBERED NAUTILUS The Chambered Nautilus is located near the Dark Cluster section of the Aquarium. OCTOPUS There are no tropical octopuses in the Academy. 70 DRAFT August 2010 In the California section of the Aquarium, look for our giant Pacific octopus in its own tank and the red octopus, an occasional inhabitant in the small tanks at the Tidepool. HERMIT CRABS Non-tropical hermit crabs are occasionally in the Tidepool jewel tanks. SEA STARS There are a number of non-tropical sea stars in the California Coast exhibit areas. The Water Planet includes the Blue Linkia sea star and the Chocolate Chip sea star. The Crown of Thorns Acanthaster planci (Acanthasteridae) is not displayed in the main tank because it consumes coral; it is featured in the “Dive Deeper” interactive exhibit. SEA URCHINS Look in the Seagrass Lagoon on the main floor for the Long-Spined sea urchin Diadema setosum (Diadematidae) and the Tuxedo sea urchin Mespilia globulus (Temnopleuridae) Look in the Color Cluster area of the Aquarium for the Fire Urchin Asthenosmoa varium (Echinothuriidae) RAYS Look for these freshwater stingrays at the exit of the Flooded Amazon area. The tropical Reef Lagoon includes the Javanese Cownose Ray Rinopter javanica (Myliobatidae), the Honeycomb Stingray Himantura uarnak (Dasyatidae), and the Bowmouth Guitarfish Rhina ancylostom (Rhinobatidae). SHARKS There are several non-tropical shark species in the Rocky California Coast: the leopard shark is in the California Coast main tank, the swell shark is in the Southern California tank, the horn shark is in the Giants Tank. The tropical shark species, Blacktip Reef Shark Carcharhinus melanopterus, is located in the Reef Lagoon. PARROTFISH There are no parrotfish at the Academy because they are destructive to coral. PUFFERFISH There are no live pufferfish in the Academy. TRIGGERFISH There are several species of triggerfish in the Phillipine Coral Reef tank. SEAHORSES Look for seahorses, seadragons and pipefish in the Water Planet. August 2010 71
