Big-belly seahorse
Encyclopedia
The big-belly seahorse or pot bellied seahorse, Hippocampus abdominalis, is one of the largest seahorse species in the world with a length of up to 35 cm.
.
with a vertical stance - when not swimming it coils its prehensile tail around any suitable growth, such as seaweed
, waiting for plankton
ic animals to drift by when they are sucked up by the small mouth set at the tip of the snout much like a vacuum cleaner. Seahorses are voracious feeders, eating mainly crustacean
s, such as shrimps, and other small animals living among the seaweed such as copepod
s and amphipods. They do not masticate so they can eat to excess because of their small gut tract. Each eye moves separately making it easier for them to see food and predators.
It is quite easy to distinguish males from females. The male have a smooth soft pouch-like area at the base of its abdomen
between where the stomach meets the tail on the front side. Males also have a fin here but it is less obvious. The female will have more of a pointed stomach with a very obvious fin at the base of the stomach.
Large-belly seahorses have a very intricate social life every morning, the female travels to her mate and they entwine tails and 'dance' together for six to 10 minutes, changing colour and promenading across the seabed. In wild seahorse populations, monogamy appears to be the rule rather than the exception. It is thought that such pair bonding is reinforced by daily greetings which are performed only with an individual's partner
Courtship initiation involves a series of colour changes and postural displays. Dilating the opening of their brood pouch slightly, males inflate the pouch to balloon-like proportions with water by swimming forwards, or by pushing their body forwards in a pumping action, then closing the pouch opening. At the same time they lighten their pouch in colour to white or light yellow. Males also brighten their overall body coloration, typically intensifying the colour yellow. Males repeatedly approach their selected female with their head tucked down, and dorsal
and pectoral fins rapidly fluttering.
If the female is not receptive she ignores the male, who then looks for another potential mate. If no females are receptive the male stops displaying and deflates the pouch by dilating the pouch opening and bending forwards, expelling the water inside. If a female is receptive to a courting male, she reciprocates with her own colour changes and head tucking, typically intensifying the lighter colours such as yellow and white, highlighting the contrast between these colours and their overall darker blotching and banding patterning. A series of short bursts of swimming together in tandem then ensues, sometimes with tails entwined, or with the female tightly rolling her tail up. This has often been described as ‘dancing’. After coming to rest, the male attempts to get the female to swim towards the water surface with him by repeatedly pointing his snout upwards.
If the female responds by also pointing her snout upwards then the final stage of courtship follows. This involves both males and females swimming directly upwards towards the water surface with both their heads pointing upwards and tails pointing straight down. If they reach the water surface, one, or both seahorses, can often be seen and heard to snap their heads. To transfer her eggs to the male, the female faces the male, slightly above him. Pressing the base of her abdomen against the male's pouch she then squirts her eggs through the opening in the front of his dilated pouch.
The male seahorse can give birth to up to 721 babies at a time. Their colouring is a variable shade of brown, mottled with yellow-brown and with darker splotches. The tail is often circled with yellow bands. In deeper water where the tail is anchored to other colourful forms of life, such as sponges and hydroid
s, they often take on these colours.
Habitat
The big-belly seahorse is found in large rock pools at low tide, amidst seaweed. Juveniles are pelagic or attached to drifting seaweedSeaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
.
Description
The big-belly seahorse has a forward-tilted, long-snouted head, distended but narrow pot belly, and a long coiled tail. It swims using its dorsal finDorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
with a vertical stance - when not swimming it coils its prehensile tail around any suitable growth, such as seaweed
Seaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
, waiting for plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
ic animals to drift by when they are sucked up by the small mouth set at the tip of the snout much like a vacuum cleaner. Seahorses are voracious feeders, eating mainly crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, such as shrimps, and other small animals living among the seaweed such as copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s and amphipods. They do not masticate so they can eat to excess because of their small gut tract. Each eye moves separately making it easier for them to see food and predators.
It is quite easy to distinguish males from females. The male have a smooth soft pouch-like area at the base of its abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
between where the stomach meets the tail on the front side. Males also have a fin here but it is less obvious. The female will have more of a pointed stomach with a very obvious fin at the base of the stomach.
Large-belly seahorses have a very intricate social life every morning, the female travels to her mate and they entwine tails and 'dance' together for six to 10 minutes, changing colour and promenading across the seabed. In wild seahorse populations, monogamy appears to be the rule rather than the exception. It is thought that such pair bonding is reinforced by daily greetings which are performed only with an individual's partner
Reproduction
In the wild, the breeding can commence when the seahorses are about one year old and experiments show that this can be reduced to about eight months when in captivity. Breeding in big-belly seahorses is usually observed during spring/summer.Courtship initiation involves a series of colour changes and postural displays. Dilating the opening of their brood pouch slightly, males inflate the pouch to balloon-like proportions with water by swimming forwards, or by pushing their body forwards in a pumping action, then closing the pouch opening. At the same time they lighten their pouch in colour to white or light yellow. Males also brighten their overall body coloration, typically intensifying the colour yellow. Males repeatedly approach their selected female with their head tucked down, and dorsal
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
and pectoral fins rapidly fluttering.
If the female responds by also pointing her snout upwards then the final stage of courtship follows. This involves both males and females swimming directly upwards towards the water surface with both their heads pointing upwards and tails pointing straight down. If they reach the water surface, one, or both seahorses, can often be seen and heard to snap their heads. To transfer her eggs to the male, the female faces the male, slightly above him. Pressing the base of her abdomen against the male's pouch she then squirts her eggs through the opening in the front of his dilated pouch.
The male seahorse can give birth to up to 721 babies at a time. Their colouring is a variable shade of brown, mottled with yellow-brown and with darker splotches. The tail is often circled with yellow bands. In deeper water where the tail is anchored to other colourful forms of life, such as sponges and hydroid
Hydroid
-Marine biology:Hydroids are a life stage for most animals of class Hydrozoa, small predators related to jellyfish.-Botany:In mosses, hydroids form the innermost layer of the stem of long, colourless, thin walled cells of small diameter.The cells are dead and lack protoplasm.They function as water...
s, they often take on these colours.