Dwarf Seahorse

The dwarf seahorse (Hippocampus zosterae) is a small seahorse found in the Western Atlantic Ocean. They are also known as little seahorses or pygmy seahorses. 

Description:

The maximum length of a dwarf seahorse is just under 2 inches. Like many other seahorse species, it has a variety of color forms, which range from tan to green to almost black. Their skin may be mottled, have dark spots, and covered in tiny warts. These seahorses have a short snout, and a coronet on top of their head that is very high and column-like or knob-like in shape. They may also have filaments extending from their head and body. 

Dwarf seahorses have 9-10 bony rings around their trunk and 31-32 rings around their tail. 

Classification

• Kingdom: Animalia
• Phylum: Chordata
• Class: Actinopterygii
• Order: Gasterosteiformes
• Family: Syngnathidae
• Genus: Hippocampus
• Species: Zosterae

Habitat and Distribution

Dwarf seahorses live in shallow waters populated with seagrasses. In fact, their distribution coincides with the availability of seagrasses. They may also be found in floating vegetation. They live in the Western Atlantic Ocean in southern Florida, Bermuda, Bahamas and the Gulf of Mexico.

Feeding

Dwarf seahorses eat small crustaceans and tiny fish. Like other seahorses, they are "ambush predators," and use their long snout with a pipette-like motion to suck in their food as it passes by.

Reproduction

The breeding season for dwarf seahorses runs from February to November. In captivity, these animals have been reported to mate for life.

Dwarf seahorses have a complex, four phase courtship ritual that involves color changes, performing vibrations while attached to a holdfast. They may also swim around their holdfast. Then the female points her head upward, and the male responds by also pointing his head upward. Then they rise up into the water column and intertwine tails. 

Like other seahorses, dwarf seahorses are ovoviviparous, and the female produces eggs that are reared in the male's brood pouch. The female produces about 55 eggs which are about 1.3 mm in size. It takes about 11 days for the eggs to hatch into miniature seahorses which are about 8 mm in size. 

Conservation and Human Uses

This species is listed as data deficient on the IUCN Red List due to a lack of published data on population numbers or trends in this species.

This species is threatened by habitat degradation, especially because they rely on such shallow habitat. They also are caught as bycatch and caught live in Florida waters for the aquarium trade.

In the U.S., this species is a candidate for listing for protection under the Endangered Species Act.

References and Further Information:

• Irey, B. 2004. "Hippocampus zosterae". Animal Diversity Web. Accessed September 30, 2014
• Lourie, S.A., Foster, S.J., Cooper, E.W.T. and A.C.J. Vincent. 2004. A Guide to the Identification of Seahorses. Project Seahorse and TRAFFIC North America. 114 pp.
• Lourie, S.A., A.C.J. Vincent and H.J. Hall, 1999. Seahorses: an identification guide to the world's species and their conservation. Project Seahorse, London. 214 p. via FishBase, September 30, 2014.
• Masterson, J. 2008. Hippocampus zosterae. Smithsonian Marine Station. Accessed September 30, 2014.
• NOAA Fisheries. Dwarf Seahorse (Hippocampus zosterae). Accessed September 30, 2014.
• Project Seahorse 2003. Hippocampus zosterae. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Accessed September 30, 2014.