Download Watanabe, T et al (1983). Nutritional values of live organisms used

Biological Synopsis of the
Long Snouted Seahorse,
Hippocampus reidi
Figure 1: Devaney, J (2011). A breeding pair of seahorses. [Photo].
By Thomas Wetherill, FdSc Marine Science
Falmouth Marine School
Contents
University of Plymouth
Page Number
1.1 Taxonomy
3
2.1 Identifying Features
4-5
3.1 Internal and External Anatomy
6-7
4.1 Natural Geographic Distribution
8
5.1 Life Cycle and Reproduction
9-10
6.1 Biotic and Abiotic Requirements
11-12
7.1 Nutritional Requirements
13-14
8.1 Life Support Requirements
15
9.1 Key Pathogen
16
10.1 Conservation Issues
17
11.1 Legislative Requirements
18
12.1 Extraordinary Issues
19
13.1 Bibliography
20-26
2|Page
Falmouth Marine School
University of Plymouth
1.1 Taxonomy
Common Names: Longsnout seahorse, Brazilian seahorse, Slender Seahorse
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Superclass: Osteichthyes
Class: Actinopterygiio
Subclass: Neopterygii
Infraclass: Teleostei
Superorder: Acanthopterygii
Order: Syngnathiformes
Suborder: Syngathoidei
Family: Syngnathidae
Subfamily: Hippocampinae
Genus: Hippocampus
Species: reidi
Seahorses, sea dragons and pipefish are all part of the family Syngnathidae which
means fused jaw.
3|Page
Falmouth Marine School
University of Plymouth
2.1 Identifying features
Seahorses are part of the genus Hippocampus, derived from the Greek words
for horse and sea monster. During the Oligocene period around twenty million years
the seahorses are thought to have diverged from the other syngnathids when they
developed their upright position (Casey, S.P et al. 2004). Due to environmental
changes at the time the global amounts of sea grasses in coastal habitats was
greatly increased which led to a mass migration into these new habitats. The
syngnathids that dwelled here evolved the upright position which would have been
favoured in the new habitat without affecting speed or the ability to remain
camouflaged. The pipefish, however never entered this new habitat so there was no
evolutionary need to evolve into an upright position meaning they maintained their
horizontal body shape like the majority of fish found in the ocean.
The longsnout seahorse, Hippocampus reidi, when fully matured can reach an
adult height of between 4” to 7” /9.5-17.5cm measured from the top of the coronet to
the tip of the extended tail (Koldeway, H et al. 2005; Lourie, S.A et al. 2004; Lourie,
S.A et al. 1999). A massively exploited species referred to as the Brazilian or
longsnout seahorse in the fishing trade. It is a key ingredient in many oriental
medicines as well as being exported for ornamental purposes or live for aquaria
(Koldeway, H et al. 2005).
Their coronet on the top of the head (see Figure 4) is a low to medium height
and is rounded rather than pointed but can be quite large in size and convoluted in
appearance giving it the look of a crumpled up sheet of paper, they also hold their
head at a right angle to their body. They usually do not have pronounced nose or
eye spines (see Figure 4) but can have rounded tubercles instead but can just as
often have none (see Figure 2) (Lourie, S.A et al. 1999). Like all seahorses,
Hippocampus reidi have two eyes that can move independently of each other.
Their colour varies greatly from brown, black, yellow, orange and red with
white and dark spots dotted over the body, mainly the tail (Koldeway, H et al. 2005;
Lourie, S.A et al. 1999). Their colour changes with stress, light and other changes to
their environment, they are known to darken when removed from light and stressed
and lighten when they are preparing to breed or are comfortable.
4|Page
Falmouth Marine School
University of Plymouth
The species may be found with bands across the central body and the males
are often a more mottled colour compared to the females. They also have other
distinctive characteristics including broad, almost double cheek and eye spines; a
long, thick snout of around 2cm; usually no skin appendages and a narrow body.
Another good indicator of the species is the gestation period. Hippocampus reidi
have a fourteen day gestation period at 24-28°C with a potential brood size of up to
1600. The eggs are generally oval in shape and have a faint orange colour tinge.
Once born the juveniles tend to be around 8-11mm in length and research suggests
that this initial juvenile stage may be pelagic rather than benthic which would help
this species feed on their desired
planktonic food (Koldeway, H et al.
2005).
Figure 2: Devaney, J (2011). A longsnout seahorse.
[Photo].
5|Page
Falmouth Marine School
University of Plymouth
3.1 Internal and external anatomy
External Anatomy
Syngnathids are not like other teleosts (bony fish) as
instead of having an internal bone structure they have a
semi-flexible stiff body that is elongated and layered with
bony plates and rings. Bony plates join together and create
ridged rings or ‘dermal cirri’ on the body, tail and trunk, the
number of these rings vary with each species of seahorse.
These plates give the syngnathids a rigid body meaning
that they can only move by rapidly beating their fins, this
means they are quite slow in comparison to other fish but
Figure 3: Driscoll, C (2004). Parts of
the Body. [Photo].
have increased control over their movements allowing them
to move with precision and also hover for extended periods of
time in the same place.
Seahorses are easily identifiable by the external features
found on the head and body, features including the
variations of the coronet, the length of the nose spine and
Figure 4: Driscoll, C (2004). Parts of
the Head. [Photo].
snout, the number of tail and body rings found and also
the size, shape and number of pectoral and dorsal fins
(see Figures 3 and 4). All species of seahorse have two
eyes that are able to move independently of one another
giving them the ability to look forward and backwards at
the same time.
The males and females tend to be slightly
morphologically different as well (see Figure 5) with the
Figure 5: Driscoll, C (2004). Sexual
characteristics. [Photo].
males being slightly more slender, having fewer or smaller spines and having a
brooding pouch on its’ abdomen. Colours can vary massively between the two
genders as well with changes occurring when the body reacts to environmental
changes, breeding, mating and brooding. Size can vary greatly between species,
height is measured from the top of the snout to the tip of the fully extended tail and is
measured using a metal straightening device not suitable for live specimens.
6|Page
Falmouth Marine School
University of Plymouth
Circulatory system
Seahorses are part of the bony fish class, Osteichtyes and have a two-part
closed circulatory system. They have a single atrium and ventricle which make up
the heart organ and pumps blood around the body with the outflow from the ventricle
going to the gills. The liver of the seahorse plays an important role in the
detoxification of the blood as well as the kidneys that help filter it and are positioned
along the vertebral column.
Digestive System
Seahorses have a severely reduced stomach so absorb food as soon as they
eat it meaning they have to eat most of the time to be able to survive. The intestines
start at the snout where food enters, passes through the body and gut of the
seahorse before exiting at the anal vent. Seahorses do not have a true pancreas but
rather pancreatic tissue dispersed in the liver that helps produce bile to aid in
digestion. This pancreatic tissue is termed ‘hepatopancreas’ in most fish.
Respiratory System
The gills make up the majority of the respiratory system of seahorses like with
most other fish. The gills of a seahorse are known as tufted due to their irregular
crumpled shape which appears to be attached to stems. Oxygen that is dissolved in
the water is absorbed through the cell thin structure known as the gills when water is
passed over the gill opening/ ‘the operculum’, and captured by the finger like primary
and secondary lamellae which help give the gills a very large surface area and aid in
the absorption of oxygen. The gills are made up of very delicate tissues so teleosts
have 4 gill arches on either side of the head which have forward facing interlocking
spines known as gill rakers that protect the gill tissue behind them. Because the gills
are so cell thin the blood pumps very close to the surface allowing rapid gas
exchange of oxygen into the body and waste gases like carbon dioxide out into the
surrounding waters.
7|Page
Falmouth Marine School
University of Plymouth
4.1 Natural geographic distribution
The long snout seahorse is found across a variety of waters that they are native too
spanning across the Bahamas, Barbados, Belize, Bermuda, Brazil, Columbia, Cuba,
Grenada, Haiti, Jamaica, Panama, United States (Florida, North Carolina), and
Venezuela (IUCN. 2008; Kuiter, R.H. 2003; Lourie et al. 1999) (see Figure 6). They
can be found at depths between 15-55m around coastal areas as their preferred
habitats; sea grasses, gorgonian corals and sargassum are found in these regions
with smaller specimens more common in shallower waters (Aquatic Community.
2008). Hippocampus reidi can be found in small groups of up to 4 individuals
(Koldeway, H et al. 2005)
Figure 6: IUCN (2008). Natural distribution of Hippocampus reidi. [Photo].
8|Page
Falmouth Marine School
University of Plymouth
5.1 Life cycle and reproduction
Male Pregnancy
All members of the syngnathids all share common evolutionary traits: male
pregnancy and monogamy. The female carries the eggs until courtship and mating
occurs, in which time the eggs are transferred by the females ovipositor to
specialised brooding pouches located on the abdomen of the male seahorse where
they are fertilised (see Figure 5). The courtship dance and mating can last for
several days. All post fertilisation care such as nourishment and osmoregulation is
taken care of by the male which has evolved morphological traits to do this (Wilson,
A.B. 2004).
Monogamy
During a mating cycle males are completely monogamous only accepting
eggs from one female though they can switch partners between cycles. Some pair
bonded seahorses have been observed to conduct in daily greetings (see Figure 1)
that extend to courtship once the male has given birth (Lourie, S.A et al. 2004).
Gestation and Birth
Once H.reidi reach sexual maturity at around sixty days they are able to
successfully breed and their growth rate slows down (da Hora, M.D.C & Joyeux, J.C.
2001). Recorded examples of mating shows that the actual process of egg transfer
and fertilisation lasts around twenty five minutes and that like all species of the
Syngnathid family, the young are born as miniature replicas of the adult and increase
in size when they mature rather than change appearance (Rosa, I.L et al. 2007;
Garrick-Maidment, N. 1998). Once males become pregnant they become less mobile
and less social and conserve their energy and remain out of sight for protection, they
have been observed to occasionally stop feeding meaning that some ‘treat’ foods
like mysis should be provided to encourage feeding again. Once birth begins the
pouch takes on a black or pinkish hue and the seahorse positions itself before the
new borns are expelled by approximately one hundred for every tail beat against the
body with the heights of the new born juveniles being around 8mm each (Rosa, I.L et
al. 2007). H.reidi can give birth to 400-1600 juveniles per pregnancy cycle with the
9|Page
Falmouth Marine School
University of Plymouth
gestation period being approximately fourteen days. The dispersal of the juveniles
begins shortly after.
Figure 7: Steene, R.C (2003). H.reidi. Female yellow, male dark red.
[Photo].
10 | P a g e
Falmouth Marine School
University of Plymouth
6.1 Biotic and abiotic requirements
Generally the larger and more common species are kept due to their relative
easiness to keep for the more experienced aquarists and that they have all have
been found to be easily encouraged to breed in a healthy system. They must be
given large tanks based on their size in order for them to be kept happy as well as
making any sudden spikes of ammonia or others to be less immediately effective.
Hippocampus reidi can be kept in relatively shallow tanks (60cm height or less)
unlike most similarly sized seahorses but it should be at least wider then it is high to
avoid additional stress in the future and also to allow for increased breeding, tanks
with several paired seahorses are generally much more successful than a tank with
few (Kuiter, R.H. 2003).
Light plays an important role in the quality of the lives of the seahorses,
especially with breeding pairs and should ideally come from the natural light provided
by the sun. If artificial light is used the sunrise and sunset should be compensated
for with a slow addition and subtraction of light intensity with a dimmer switch with
the ratio of dark and light being 12 hours on and 12 hours off (Koldeway, H et al.
2005). This ensures that natural reactions to these light changes such as greetings,
courting and mating still occur as close to normal as possible. Species that live at
deeper depths are more sensitive to changes in light compared to shallower species
but as H.reidi can be found as deep as 60 metres it is important to be very careful
and slow with changes in light intensity throughout the day to ensure the continual
wellbeing of the species (Kuiter, R.H. 2003).
The base of the tank should be covered in live sand or be bare bottomed, no
stones or pebbles to encourage excess algal growth. It is important to remember to
add additional substrate such as rocks, artificial or live plants, netting or other
potential grabbing items to allow the subjects to fasten their tails and rest, I have
found that the best artificial fast holds are pieces of netting attached or weighed
down at the bottom of the tank but using live rock works as well. In the wild H.reidi
usually cling to small sponges or gorgonians that match their colouring to aid in their
camouflage (Kuiter, R.H. 2003). The temperature of the tanks should be kept around
24°C but a little difference isn’t a problem as long as there are no rapid fluctuations
11 | P a g e
Falmouth Marine School
University of Plymouth
in temperature as that could cause additional stress. At least a 75 watt heater should
be used but any higher wattage should be fine.
Water quality is important to maintain as many factors can affect it drastically.
The water in the tank should be kept between 30-35‰ but no higher, as long as you
try to keep the seahorses in as consistent a salinity as possible they should be fine.
Important factors to be monitored in the tank are levels of ammonia, nitrite, nitrate
and pH. Ammonia is very damaging to marine life so optimum levels would be zero
but as long as levels remain lower than 0.25 parts per million (ppm) and there is
regular siphoning of decomposing organic matter such as faeces or uneaten food the
species should not be affected by this low level. Nitrite can be a serious problem and
usually can spike after a large ammonia amount in the tank: it causes various health
problems even in small amounts and typical symptoms include seahorses gasping
for breath at the surface of the tank, seahorses remaining near water outlets
continuously, rapid gill movements and the gills turning a tan or brown colour. It can
cause nitrite poisoning which causes mass replication of methemoglobin which
causes the blood to turn brown and limits ability to carry oxygen, the common name
for this is ‘brown blood disease’ and to avoid this levels of nitrites should be kept
below 0.25 ppm (Sharpe, S. Unknown). The effects of nitrates are far less
understood and they are not thought to damage marine life until reaching around 100
ppm when they can start causing stress and affecting reproduction as well as
stunting growth of fry and juveniles. Levels should be kept lower than 30 ppm to
avoid any problems. For all of these issues the main preventer is simply frequent
water tests and siphoning out additional organic matter but if spikes in these
chemicals do become a problem then large daily water changes up to 60% over a
period of a few days should sort the problem out quickly as well as reducing the level
of feed, adding aeration to tanks and increasing salinity.
12 | P a g e
Falmouth Marine School
University of Plymouth
7.1 Nutritional requirements
Roos et al, 2009 stated that Hippocampus reidi, like all Syngnathid fish, have
a very morphologically different method of feeding compared to other fish. Whilst
other fish feed by creating an anterior to posterior flow of water in their expandable
head to create suction in a uni-directional direction, seahorses utilize their mouths to
make rapid sucking movements close to the prey in order to feed. The maximum
flow velocity is not found in the mouth channel, like with most teleosts, but rather in
the narrow channel in the buccal cavity. They have specialised features such as
elongated snouts and an immobile pectoral girdle which allows for this to occur
(Leysen, H. 2011). They are visual feeders in that they have to see their prey before
they hunt it rather than relying on scent or chemical indicators like some fish (Lee,
H.R & O’Brien, K.M.D. 2011). Hippocampus reidi, when studied in the wild, have
been found to be rather sedentary predators waiting for their prey to come to them
most of the time rather than stalk them (Felicio, A.K.C. 2006).
In captivity adults are normally fed 2-3 times a day over a period of about 6
hours. In nature H.reidi would feed on a variety of copepeds, rotifers and newly
hatched brine shrimp (Leadsom, S. 2008). Chang, M.C (2000), stated that most of
the strains of artemia found in the aquatic sense are deficient in Highly Unsaturated
Fatty Acids (HUFAs) making them a poor long term food source for many fish
species. In order to combat this a variety of foods should be used including mysid
shrimp and artemia enriched with slurred fish meal or phytoplankton. All this excess
HUFAs increases the fry’s’ and adults chance of survival and the increased nutrition
also helps boosts immune responses to stressful factors affecting them or their
environment.
Juveniles
When preparing the feed for H.reidi a high standard of hygiene should be
maintained to prevent any bacteria or infiltrating algae to get into the seahorse
system, this is extremely important to regulate for the seahorses continual growth
and survival. Using a nutritious food that provides all the essential components of the
seahorses diet increases the size of the offspring produced making it easier to keep
13 | P a g e
Falmouth Marine School
University of Plymouth
juveniles as they can be fed larger foods like brine shrimp/ artemia nauplii as their
first foods.
It is crucial to ensure a variety in diet for the first few weeks of life as H.reidi
normally remain so small in their juvenile stage that they often die of malnutrition due
to not being able to take larger more nutritional foods (Leadsom, S. 2008). In the wild
H.reidi have a vast amount of potential foods made up of a planktonic soup of lipid
rich zooplankton. They do not often take any frozen foods so a diet of live feed is
often required consisting of artemia, copepods and rotifers that are small enough to
be fed on easily with rotifers being mainly used as they are small enough to be eaten
by even the smallest seahorse After the first few weeks when the babies have
reached juvenile size they can begin being fed a more varied diet consisting of mysid
shrimp and different enriched artemia (Koldeway, H et al. 2005).
14 | P a g e
Falmouth Marine School
University of Plymouth
8.1 Life support requirements
When setting up a suitable system for these fragile creatures there are many
factors to take into account. Being such a slow moving and gentle creature
seahorses would be better suited to being placed in seahorse specific tanks with no
fast aggressive fish that could out compete them. Try and avoid adding any clams as
they may close on a seahorse and species of crabs that could be detrimental to their
health and survival in a tank. Adding fast holds in the tank is also an important step,
artificial or live reed like plants similar to sea grasses would be best but these
creatures will hold on to most anything. The more fast holds added though the less
chance that they will attach to any of the filtration or heating devices within the
system and risk damaging themselves.
From personal experience I have found that this species can be successfully
kept with a turnover rate of 3 times an hour with 50 litre tanks but it is recommended
by other sources that 6 litres/ minute is required but as long as water quality is
regularly monitored and you remember that ‘fish don’t pollute, feed and feeding
pollute’ (Chen & Cho) and don’t overfeed them there should be no problem. These
creatures come from tropical/ subtropical waters so are used to a warm temperature
of between 20-28ºC so an average maintenance temperature of around 24ºC is
ideal. As long as temperature is not changed rapidly but by a degree every few hours
they should adapt quickly enough to avoid excess stress. Levels of nitrites, nitrates
and ammonia should be kept as low as possible without regular water monitoring,
maintenance and changes if anything spikes to reduce the risk of damage to the
species.
15 | P a g e
Falmouth Marine School
University of Plymouth
9.1 Key pathogen
Seahorses, like many cultured fish species, do not respond well to stress
caused by high stock densities or environmental changes which make them more
vulnerable to infection. In lab observations a number of infectious organisms
affecting seahorse species were discovered including; cestodes, microsporidians,
fungi, ciliates, trematodes and marine leaches (Koldeway, H & Martin-Smith, K.M.
2010).
The main diseases that these species bring that are of a major concern for
seahorses are vibriosis and mycobacteriosis (Koldeway, H. 2005). Vibriosis is easier
to deal with as it can be treated with antibiotics though it affects various bacterial
strains with varying levels of success and there have been limited testing on species
due to regulatory and ethical implications. Vibriosis can come from live food such as
artemia which has led to feed being treated with antibiotics before being fed to a
species in order to reduce the chance of infection. Mycobacteriosis is not treatable
and is considered a disease of special concern for seahorses (Koldeway, H. 2005).
In aquatic systems another major concern for seahorses is gas entrapment issues or
‘gas bubble disease’ which causes problems in the brood pouch on the male, the
emphysema on the tail and can cause over inflation of the swim bladder. Treatments
used to help solve this issue include aspiration of air bubbles and/ or the use of
antibiotics (Koldeway, H. 2005).
Due to a seahorses unique anatomy there are many challenges related to
their health care if there are any difficulties. The hard plated body makes injections
difficult and the two part bronchial chambers make any attempts to clear or make
biopsies to the gills difficult. This means that the best methods of managing disease
is prevention by initialling quarantining any new species arriving in the aquatic facility
before they are introduced to a system. Also maintaining a good in tank environment
as well as maintaining a good diet for the species will help reduce any possible
health problems that could occur.
16 | P a g e
Falmouth Marine School
University of Plymouth
10.1 Conservation issues
Hippocampus reidi are one of two species of seahorse found around Brazil, a
massively fishing orientated country, and due to lack of conservation effort they are
heavily exploited. In a price declining market for fish, seahorses provide a highly
economical and marketable product that can be exported worldwide for high cost
and relatively small effort. The trade of seahorses has the potential to be a great
alternative to fishing if managed sustainably however the declining populations of
seahorses worldwide are still being massively exploited and mostly unchecked. Not
many protocols have been initiated in the main Indo-Pacific countries responsible for
the majority of exporting seahorses further decreasing global numbers of every
species (Job, S.D et al. 2002).
Conservation efforts have been made that work on the principles of
discussion rather than outright banning. The main issues with the decline of the
seahorses is the high demand for them in Asian countries with long legacies in the
exploitation of these species. Ornamental and medical uses that date back
thousands of years and are not fully understood make it difficult to make
compromises for the use of seahorses. The apparent medical benefits of seahorse
based ointments and powders have not been scientifically discovered so no
alternative will be accepted as they can be claimed not to provide the same effects.
The use of seahorses for ornaments and good luck charms are based mainly on
beliefs and superstition so yet again no adequate substitute can be provided. In
order to combat this there have been attempts to encourage the main consumers to
try and preserve and sustain global populations allowing their continual exploitation
without causing the extinction of the species which is nobody’s best interests. A
village in the Philippines, Handumon, has been encouraged to craft and sell
handicrafts to replace the profits that would have been made from seahorse
exploitation and organisations such as Project Seahorse has aided in the set up of
protective areas in these places and also helping make programs in these areas to
teach local farmers in the conservation and preservation of seahorse species. When
prevention of exploitation is not possible other attempts are used such as the use of
special mesh cages that capture adult males but allow the young and newborns to
escape thus allowing the chance for future reproduction (Becker, J. 2001).
17 | P a g e
Falmouth Marine School
University of Plymouth
11.1 Legislative requirements
Seahorse populations are a cause for concern due to the vast market for
various uses for them. All seahorses are listed on CITEs as vulnerable on the red list
of endangered species in the International Union for the Conservation of Nature.
This puts severe restrictions on the export and import of all seahorses, alive or dead
which dramatically helps in seahorse conservation as global fishing will reduce as
the available market decreases as well as helping to eliminate the wild seahorse
trade in the aquarium trade. (IUCN, 2008; Olivotto, I et al. 2008). They are a popular
ornamental species as well as being traded to be used in various traditional
medicines, remedies and other product forms in various cultures around the world in
high volumes (Zhang, D. 2010; Oliveira, T.P.R et al. 2007; Woods, C.M.C. 2007;
McPherson, J.M & Vincent, A.C.J. 2004; Payne, M.F & Rippingale, R.J. 2000).
They are targeted by divers that visit areas high in sea grasses and corals
and are commonly poached along with sea cucumbers and a number of different
gastropods (Salin, K.R et al. 2005). This overlong unsustainable exploitation of the
seahorse species has caused vast gaps in our knowledge of their biology and
ecology due to them becoming increasingly difficult to find (Woods, C.M.C. 2002).
This is not helped by the gradual degradation and destruction of their habitats in
coastal areas including coral reefs, sea grasses and mangroves (Olivotto, I et al.
2008). In 175 countries the export of seahorses has been limited to sustainable
levels now in place to help protect them and also allow their numbers to replenish
(Vincent, A.C.J et al. 2011).
18 | P a g e
Falmouth Marine School
University of Plymouth
12.1 Extraordinary issues
In the trade of seahorses it is estimated that for every one million seahorses
taken from the wild, less than 1000 survive for longer than six weeks (The Seahorse
Trust. 2010).
Though seahorses beat their fins around 50 times a minute they are actually
very poor swimmers. Despite their lack of mobility seahorses are very manoeuvrable
able to move up, down and backwards.
19 | P a g e
Falmouth Marine School
University of Plymouth
References
Aquatic Community (2008). Long Snout Seahorse. [Online]. Available at:
http://www.aquaticcommunity.com/Sea-horses/longsnout.php (accessed on 22/02/12
Amirkolaie, A.K (2011). Reduction in the environmental impact of waste discharged
by fish farms through feed and feeding. [Journal]. Reviews in Aquaculture. 3 (1),
p19-26.
Ashley-Ross, M.A (2002). Mechanical properties of the dorsal fin muscle of seahorse
(Hippocampus) and pipefish (Syngnathus). [Journal]. Journal of Experimental
Biology. 293 (6), p561-577.
Baldwin, C (06/12/2011). Most seahorse species have very similar requirements
when kept in captivity. [Personal Quote].
Becker, J (2001). Seahorses: Characteristics and Conservation (Final Paper #2).
[Journal]. Tropical Marine Ecology. Unknown (Unknown), p Unknown.
Berzins, I.K et al (2010). Sound, stress, and seahorses: The consequences of a
noisy environment to animal health. [Journal]. Aquaculture. 311 (1-4), p129-138.
Casey, S.P et al (2004). The origin and evolution of seahorses (genus
Hippocampus): a phylogenetic study using the cytochrome b gene of mitochondrial
DNA. [Journal]. Molecular Phylogenetics and Evolution. 30. p261–272.
Chang, M.C (2000). Improvements of culture techniques for the seahorse
Hippocampus sp. Masters Thesis. James Cook University.
Da Hora, M.D.C & Joyeux, J.C (2001). Closing the reproductive cycle: Growth of the
seahorse Hippocampus reidi (Teleostei, Syngnathidae) from birth to adulthood under
experimental conditions. [Journal]. Aquaculture. 292 (1-2), p37-41.
Deeble, M & Stone, V (1985). Mark Deeble and Victoria Stone (1985). A port that
could threaten marine life in England's Fal Estuary. [Journal]. Oryx. 19 (Unknown),
p74-78.
20 | P a g e
Falmouth Marine School
University of Plymouth
Driscoll, C (2004). Seahorse Anatomy. [Online]. Available at: www.seahorse.org
(accessed on 14/02/12).
Felicio, A.K.C. (2006). Feeding behaviour of the longsnout seahorse Hippocampus
reidi Ginsburg, 1933. [Journal]. Journal of Ethology. 24 (3), p219-225.
Forteath, N (2001). Mariculture of Marine Species. [Journal]. Academic Press.
Unknown (Unknown), p1563.
Foster, S.J & Vincent, A.C.J (2004). Life history and ecology of seahorses:
implications for conservation and management. [Journal]. Journal of Fish Biology. 65
(1), p1-61.
Freret-Meurer, N.V & Andreata, J.V (2008). Field studies of a Brazilian Seahorse
population, Hippocampus reidi Ginsburg, 1933. [Journal]. Brazilian Archives Of
Biology And Technology. 51 (4), p743-751.
Garrick-Maidment, N (1998). A note on the status of indigenous species of seahorse.
[Journal]. Journal of the Marine Biological Association of the UK. 78 (unknown),
p691-692.
Hercos, A.P & Giarrizzo, T (2007). Pisces, Syngnathidae, Hippocampus reidi : Filling
distribution gaps. [Journal]. Check List. 3(4), p287–290.
Hoffman, E.A et al (2006). Male pregnancy and the evolution of body segmentation
in seahorses and pipefishes. [Journal]. Evolution. 60 (2), p404-410.
IUCN (2008). 2008 IUCN red list of threatened species. [Online]. Available at:
www.iucnredlist.org (accessed on 05/12/11).
Job, S.D et al (2002). Culturing the Oceanic seahorse: Hippocampus kuda. [Journal].
Zoological Society of London. Unknown (Unknown), p Unknown.
Koldeway, H & Martin-Smith, K.M (2010). A global review of seahorse aquaculture.
[Journal]. Aquaculture. 302 (Unknown), p131-152.
21 | P a g e
Falmouth Marine School
University of Plymouth
Koldeway, H et al (2005). Syngnathid husbandry in public aquaria: 2005 Manual.
[Book]. London: Zoological Society of London and Project Seahorse.
Kuiter, R.H (2003). Seahorses, Pipefishes and their relatives, a comprehensive
guide to Syngnathiformes [Book]. Herts: TMC Publishing.
Leadsom, S (2008). Raising Seahorse Fry. [Online]. Available at:
http://www.ultimatereef.net/articles/seahorsefry/ (accessed on 18/03/12)
Lee, H.R & O’Brien, K.M.D (2011). Morphological and behavioral limit ofvisual
resolution in temperate (Hippocampus abdominalis) and tropical (Hippocampus
taeniopterus) seahorses. [Journal]. Visual Neuroscience. 28 (4), p351-360.
Leysen, H (2011). Musculoskeletal structure of the feeding system and implications
of snout elongation in Hippocampus reidi and Dunckerocampus dactyliophorus.
[Journal]. Journal Of Fish Biology. 78 (6), p1799-1823.
Lourie, S.A et al (2004). A guide to the identification of seahorses. [Book].
Washington D.C: Project Seahorse and TRAFFIC North America.
Lourie, S.A et al (1999). Seahorses: an identification guide to the world`s species
and their conservation. [Journal]. Project Seahorse. Unknown (Unknown). p214.
Luiz, A et al (2008). Assessing diet composition of seahorses in the wild using a nondestructive method: Hippocampus reidi (Teleostei: Syngnathidae) as a study-case.
[Journal]. Neotropical Ichthyology.6(4), p637-644.
Lunn, K.E & Hall, H.J (1999). Briefing Documents for the First International Aquarium
Workshop on Seahorse Husbandry, Management, and Conservation. [Book].
Chigago: Project Seahorse. p98.
Mai, A.C.G & Velasco, G (2012). Population dynamics and reproduction of wild
longsnout seahorse Hippocampus reidi. [Journal]. Journal of the Marine Biological
Association of the United Kingdom. 92 (2), p421-427.
22 | P a g e
Falmouth Marine School
University of Plymouth
McPherson, J.M & Vincent, A.C.J (2004). Assessing East African trade in seahorse
species as a basis for conservation under international controls. [Journal]. Aquatic
Conservation: Marine and Freshwater Ecosystems. 14(5). P521-538.
Mendes, A.C et al (2010). “Alive or Frozen Artemia: A carrier of fatty acids to fish
larvae”. [Presentation]. World Aquaculture. San Diego: CA, p1-20.
Natural England (2009). Seahorses and seagrass FAQ. [Online]. Available at:
http://www.naturalengland.org.uk/regions/south_west/ourwork/seahorses.aspx.
(Accessed on 09/12/11).
NSW Department of Primary Fisheries (2008). Seahorses and their relatives.
[Online]. Available at:
www.fisheries.nsw.gov.au/threatened_species/general/synganathids (accessed on
15/02/12)
Oliveira, T.P.R et al (2010). Novel sex-related characteristics of the long snout
seahorse Hippocampus reidi Ginsburg, 1933. [Journal] Neotropical Ichthyology. 8
(2), p373-378.
Oliveira, T.P.R et al (2007). Population characteristics, space use and habitat
associations of the seahorse Hippocampus reidi (Teleostei : Syngnathidae).
[Journal]. Neotropical Ichthyology. 5 (3), p405-414.
Olivotto, I et al (2008). Breeding and rearing the long snout seahorse Hippocampus
reidi: Rearing and feeding studies. [Journal]. Aquaculture. 283 (1-4), p92-96.
Otero-Ferrer, F et al (2010). Live prey first feeding regimes for short-snouted
seahorse Hippocampus hippocampus (Linnaeus, 1758) juveniles. [Journal].
Aquaculture Research. 41 (9), p8-19.
Pawar, H.B (2011). Effect of Background Colour of Tanks on Growth and Survival of
Juvenile Yellow Seahorse, Hippocampus kuda (Bleeker 1852), in the Pelagic Phase.
[Journal]. Israeli Journal of Aquaculture. 63 (unknown). p (unknown).
23 | P a g e
Falmouth Marine School
University of Plymouth
Payne, M.F & Rippingale, R.J (2000). Rearing West Australian seahorse,
Hippocampus subelongatus, juveniles on copepod nauplii and enriched Artemia.
[Journal]. Aquaculture. 188 (3-4), p353-361.
Pinnegar, J.K (2008). Occurrence of the short-snouted seahorse Hippocampus
hippocampus in the central North Sea. [Journal]. Cybium. 32 (4), p343-346.
Rimmer, M.A et al (1994). Effects of nutritional enhancement of live food organisms
on growth and survival of barramundi, Lates calcarifer (Bloch), larvae. [Journal].
Aquaculture Research. 25 (2), p143-156.
Roos, G et al (2009). Kinematics of suction feeding in the seahorse Hippocampus
reidi. [Journal]. The Journal of Experimental Biology. 212 (unknown), p3490-3498.
Rosa, I.L et al(2006). Collaborative monitoring of the ornamental trade of seahorses
and pipefishes (Teleostei: Syngnathidae) in Brazil: Bahia State as a case study.
[Journal]. Neotropical Ichthyology. 4(2), p247-252.
Rosa, I.L et al (2005). Fishers' knowledge and seahorse conservation in Brazil.
[Journal]. Journal of Ethnobiology and Ethnomedicine. 1 (Unknown), p (Unknown).
Salin, K.R et al (2005). Fisheries and trade of seahorses, Hippocampus spp., in
Southern India. [Journal]. Fisheries Management and Ecology. 12 (4), p269-273.
Sargent, J.R et al (1997). Requirements, presentation and sources of
polyunsaturated fatty acids in marine fish larval feeds. [Journal]. Aquaculture. 155
(unknown). P117-128.
Sharpe, S (Unknown). Nitrite Poisoning. [Online]. Available at:
http://freshaquarium.about.com/cs/disease/p/nitritepoison.htm (accessed on
15/03/12)
Silveira, R. B (2000), Desenvolvimento osteológico de Hippocampus reidi Ginsburg
(Pisces, Syngnathiformes, Syngnathidae) em laboratório. [Journal]. Brasileira de
Zoologia, 17(2). p507 – 513.
24 | P a g e
Falmouth Marine School
University of Plymouth
Sorgeloos, P et al (1987). The nutritional value of Artemia: a review. [Journal].
Artemia Reseach and its implications. 3 (556), p357-372.
Southgate, P.C & Kavanagh, K (1999). The effect of dietary n-3 highly unsaturated
fatty acids on growth, survival and biochemical composition of the coral reef
damselfish Acanthochromis polyacanthus. [Journal]. Aquatic Living Resources. 12
(1), p31-36.
Teske, P.R & Beheregaray, L.B (2009) Evolution of seahorses’ upright posture was
linked to Oligocene expansion of seagrass habitats. [Journal]. Biology Letters. 5
(Unknown), p521-523.
The Seahorse Trust (2010). Seahorse Facts. [Online]. Available at:
http://www.theseahorsetrust.org/seahorse-facts.aspx (accessed on 20/03/12).
Unknown (Unknown). Seahorse Anatomy. [Online]. Available at:
http://aquarium.ucsd.edu/Education/Learning_Resources/Secrets_of_the_Seahorse/
swf/body.swf (accessed on 17/03/12)
Vincent, A.C.J et al (2011). Conservation and management of seahorses and other
Syngnathidae. [Journal]. Journal of Fish Biology. 78 (6), p1681-1724.
Watanabe, T et al (1983). Nutritional values of live organisms used in Japan for
mass propagation of fish: A review. [Journal]. Aquaculture. 34 (-), p115-143.
Wilson, A.B et al (2001). Male Pregnancy in Seahorses and Pipefishes (Family
Syngnathidae): Rapid Diversification of Paternal Brood Pouch Morphology Inferred
From a Molecular Phylogeny. [Journal]. Journal of Heredity. 92 (2), p159-166.
Woods, C.M.C (2002). Natural diet of the seahorse Hippocampus abdominalis.
[Journal]. New Zealand Journal of Marine and Freshwater Research. 36 (4), p655660.
Woods, C.M.C (2007). Aquaculture of the Big-Bellied seahorse Hippocampus
Abdominalis. PhD. Victoria University.
25 | P a g e
Falmouth Marine School
University of Plymouth
Zhang, D (2010). Growth and survival of juvenile lined seahorse, Hippocampus
erectus (Perry), at different stocking densities. [Journal]. Aquaculture Research. 42
(1), p9-13.
Figure 1: Devaney, J (2011). A breeding pair of seahorses. [Photo].
Figure 2: Devaney, J (2011). A longsnout seahorse. [Photo].
Figure 3: Driscoll, C (2004). Parts of the Body. [Picture] [Online]. Available at:
http://www.seahorse.org/library/articles/anatomy.shtml (accessed on 14/02/12)
Figure 4: Driscoll, C (2004). Parts of the Head. [Picture] [Online]. Available at:
http://www.seahorse.org/library/articles/anatomy.shtml (accessed on 14/02/12)
Figure 5: Driscoll, C (2004). Sexual Characteristics. [Picture] [Online]. Available at:
http://www.seahorse.org/library/articles/anatomy.shtml (accessed on 14/02/12)
Figure 6: IUCN (2008). Natural distribution of Hippocampus reidi. [Map] [Online].
Available at: http://maps.iucnredlist.org/map.html?id=10082 (accessed on 15/03/12)
Figure.7:. Steene, R.C (2003). H.reidi. Female yellow, male dark red. [Photo]. In:
Kuiter, R.H (2003). Seahorses, Pipefishes and their relatives, a comprehensive
guide to Syngnathiformes [Book]. Herts: TMC Publishing. p29.
26 | P a g e