Download mb3ech08-b - Chaparral Star Academy

Sensory Perception
• Lateral line system - Eyes - fish often have
excellent vision
• Otoliths in contact with hairlike fibers
Schooling
• Behaviorally based aggregation of fish
• Most tightly schooling species have silvery
sides, which would confuse predators
• Schools sometimes in the form of “fish balls”
• Behavior related to predation; fish leaving
school are attacked successfully
• Schooling may also reduce drag, save on
energetic cost of swimming
Body temperature
• Most fishes - temperature conformers
• Tunas and relatives, some sharks, use
countercurrent heat exchange to reduce heat
loss - have elevated body temperature
• Elevated body temperature allows higher
metabolic rate, localized heating of nervous
system in some species (e.g., swordfish)
Mesopelagic Fishes
• Fish living 150-2000 m
• Fish have well developed eyes, often large
mouths for feeding on large prey
• Many have ventral photophores, serves
purpose of counterillumination camouflage to blend in with low light
from above
Chauliodus has specialized backbone to accommodate
opening of large mouth to consume prey
Location of ventral photophores on some deep-water fish
Mammals
Cetaceans: whales and porpoises
Pinnipeds: seals, sea lions, walruses
Mustelids: sea otters
Sirenians: sea cows, dugongs
Whales and Porpoises
• All belong to the Cetacea
• Odontoceti toothed whales (e.g., sperm
whale, porpoises)
• Mysticeti baleen whales - feed by means
of baleen, which strains
macrozooplankton, megazooplankton
Whales and Porpoises
• All homeothermic
• Reproduce much the same as terrestrial
mammals
• Posterior strongly muscular - propulsion
by means of flukes
Odontoceti
• Toothed, usually good hunters, feed on
squid, fish, small mammals
• Good divers
• Oral communication common
• Many species have bulbous melon, filled
with oil - function could be sound reception
• Usually social, killer whales live in pods,
maternally dominated
Odotocete Killer whale, Orcinus orca
Mysticeti
• Adults have horny baleen plates, which
strain zooplankton
• Right whales are continuous ram feeders
• Rorqual whales (e.g. Blue) are
intermittent ram feeders, periodically
squeeze water out of large mouth
chamber
Continuous
ram
feeding
Ventral furrows
Intermittent
ram
feeding
Mysticete feeding with baleen plates
Mysticetes: humpback whale breaching
Baleen plate of a beached finback whale
Other Marine Mammals
• Pinnipeds include seals, sea lions,
walruses - have hair but lack thick
blubber of cetaceans
• Sea otters belong to the otherwise
terrestrial family Mustelidae
Australian sea lion Neophoca cinerea
Sea otter, Enhydra lutris
Sirenians
• Includes manatee, dugong, extinct Stellar
Sea Cow
• Sluggish, herbivorous
• Live in inshore waters, estuaries
Florida manatee Trichechus manatus
Diving by Marine Mammals
• Must breathe at surface - no “bends”
• Problem oxygen for long dives
• Most have increased volume of arteries and
veins
• Have increased blood cell concentration
• Can decrease heart beat rate and O2
consumption
• Can restrict peripheral circulation and
circulation to abdominal organs
Gas Bubble Problems
• Upon ascent, gas bubbles may be released in
blood stream as pressure decreases - The Bends
• Not as bad a problem as you might think,
because marine mammals don’t breathe air
under pressure at depth, like human divers
• Seals and whales can restrict circulation
between the lungs and rest of circulatory
system and have small lung capacity
Seabirds
• Penguins - flightless, southern hemisphere, high
latitude, divers, insulated by blubber and feathers,
countercurrent heat exchange in circulation to
wings and feet, colonial breeders
• Petrels - great gliders, colonial breeders, often
divers from air
• Pelicans - generally tropical, heavy, diverse
hunting from diving to underwater swimming
• Gulls, auks, puffins - feed on fish, often very
abundant
Seabirds
•
•
•
•
Often colonial breeders
Believed to be monogamous
Courtship involves elaborate displays
Crowded breeding sites, often with several
species, protected from predators such as
mammals
• Feeding involves either diving or underwater
swimming
• Long-distance migration between nesting and
feeding areas is common
Seabirds
(a) emperor penguin, (b) wandering albatross, (c) magnificent
frigate bird, and (d) black-backed gull
Emperor penguin, equipped with a Critter Cam
The yellow-nosed albatross Thalassarche chlororhynchos flies with minimal effort,
owing to its extraordinarily long wings that permit it to soar on modest air drafts
Shorebirds
1.
2.
3.
4.
Include sandpipers, plovers, other groups
Great dependence upon terrestrial sites,
especially for feeding
Often migrate great distances between
feeding and nesting areas
Variety of feeding mechanisms, ranging
from probing beaks into sediment to
catching crustacea and other organisms in
the surf to clipping bivalve adductors and
scooping out bivalve flesh
Shorebirds
Shorebirds
The American black oystercatcher Haematopus bachmani (west coast U.S.)
is an effective predator on bivalve mollusks. Note its robust bill, used for
severing adductor muscles
Sea Turtles
• All nest on sandy beaches and migrate to feeding
grounds; females return to beach where they
hatched, usually repeatedly; several species shown
to use earth magnetic field to navigate in
migrations
• Feeding of adults varies (e.g., green turtle
consumes seagrasses and seaweeds, Kemp’s ridley
eat bottom invertebrates, leatherbacks eat jellyfish
• Leatherbacks distinct from other species, have
temperature conservation mechanisms, including a
countercurrent exchange heat retention
Sea Turtles
(a) a leatherback Dermochelys coriacea hatchling turtle crawling
toward the sea; (b) a female leatherback nesting at night on a beach
on Isla Culebra, Puerto Rico
Sea Turtles
Green turtle, Chelonia mydas, resting on reef in Maui
The End