Hippocampus: Some Help for Imperiled Seahorses

Seahorse Ways Co. runs a culturing farm of seahorses in Minami-Kyushu, Japanhoping to help reverse the decline of the species, according to an article published by The Yomiuri Shimbun.

Fossilized seahorse specimen - Courtesy of Jules Zalohar

Fossilized seahorse specimen - Courtesy of Jules Zalohar

The oldest fossils date back 13 million years to the Middle Miocene(found in the Tunjice Hills in Slovenia) and are of two pipefish-like species. 

Little is known about the hippocampus’behavior or interaction with their environment.  They live in shallow tropical and temperate waters throughout the world, generally among seagrass beds, mangroves and coral reefs. 

Although closely related to pipefish there are some significant differences: they have bones, not scales and swim upright.  They have a thin skin stretched over a series of bony plates visible around the trunk arranged in rings throughout their body. 

The hippocampus camouflages to blend into its surroundings and avoid detection.  Their height differs between species, ranging between 0.8 inch (2cm) and 11.8 inch (30cm).

They usually mate for life and the offspring comes from the male.  He has a pouch on its front, where the female deposits the eggs, which the male then fertilizes and incubates for two to four weeks.  Of 1000 infants born only about 0.5% survive to adulthood, which is why they have a high litter.  There is no certain data on their lifespan; estimates of a maximum of 5 years in larger species come from laboratories and aquarium observations.

Hippocampus, Gulf of Aqaba, Red Sea - Photographer: Mohammed Al Momany

Hippocampus, Gulf of Aqaba, Red Sea - Photographer: Mohammed Al Momany

Seahorses have become very popular among aquarium hobbyist.  Wild seahorses do very poorly in captivity contrary to seahorses bred in captivity.  Although these captive-bred seahorses are more expensive, they survive better than their wild counterparts and they take no toll on wild populations.

Many seahorse species are listed as threatened or even endangered on the IUCN Red List.  Their main threats are overexploitation for traditional medicines, aquarium display, tonic foods and décor, accidental fishing with non-selective gear and degradation or loss of their habitat.  Since they live in shallow coastal waters they are highly influenced by human activities.

There are over 47 species of seahorse, of which Shin Kato, head of Seahorse Ways Co. is currently breeding two, big-belly seahorse and spotted seahorse.

Read the full article at  Daily Yomiuri Online.

Read more about the hippocampus on Project Seahorse.
Read about fossil seahorses at Jule Zalohar, Ph.D.’s website.

Related links:
Fishbase.org, species summary page
Fused Jaw, more info and lots of images

Hippocampus guttulatus, Liguria, Italy - Credit: Roberto Boero/Marine Photobank

Hippocampus guttulatus, Liguria, Italy - Credit: Roberto Boero/Marine Photobank

Copyright ©  2009 by Marine Science Today, a publication of OceanLines LLC

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