The Pacific seahorse (Hippocampus ingens) is a species of fish in the Syngnathidae family. It is found in Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Mexico, Panama, Peru, and the United States. Its natural habitat is coral reefs. It is threatened by habitat loss. The genus name is derived from the Greek hippos or "horse" and campus or "sea monster."

Description

The Pacific seahorse is one of the largest of the 34 known species of seahorses in the world.

It has dorsal spines 0-0 (total); Dorsal soft rays (total): 18-21.

• Adult height: 13 to 19 centimetres (5.1 to 7.5 in)
• Rings: 11+39 (38-40)
• Snout length: 2.3 to 2.4 centimetres (0.91 to 0.94 in)
• Head length: 2.1 to 2.5 centimetres (0.83 to 0.98 in)
• Dorsal fin rays: 18-21 covering 2+1 rings
• Pectoral fin rays: 15-17
• Coronet: medium-high, tilted backwards with 5 well-defined points, or flanges at top. *Spines: variable, from low rounded bumps to well-developed blunt-tipped spines.
• Other distinctive characters: prominent, long (drooping), rounded, single cheek spines; prominent eye spine (may be broad or almost double); males commonly have a prominent keel; sexually mature females often have a dark patch below the anal fin.
• Color/Pattern: reddish-maroon, gray, yellow and gold; various shades of brown; may have fine white light and dark markings running vertically down body.

World range and habitat

The Pacific seahorse is found in the Pacific Ocean from San Diego, California, (USA) to Peru including the Galápagos Islands. It is active during the day and night. It is found in offshore waters, at depths of 2m to 30m and is occasionally caught at the surface. Are often camouflaged within brown algae or the branches of gorgonians and black coral trees where they are seen to curl their tail around the branches. Have been found in the stomachs of Pacific Yellowfin tuna and Bluefin tuna.

Feeding behavior (ecology)

Seahorses feed on bottom-swarming organisms such as mysids and other plankton.

Mysids are very small (seldom exceeding 30 mm in length) shrimp-like crustaceans which can be found throughout the oceanic water column and are also found in freshwater environments as well. Some mysids feed on small particles which they collect by grooming their body surface, whereas others are predacious on other zooplankton. Some mysids are scavengers. Marine mysids often are found in large swarms and are an important part of many fish diets. Mysids are also called "opposum shrimp", because of the brood pouch present in all mature females.

Mysids at present include more than 1,000 species, widespread over all the continents, inhabiting coastal and open sea waters, as well as continental fresh waters, several taxa occurring also in different groundwater habitats and in anchialine caves.

Seahorses lack teeth and stomachs. Prey is consumed by sucking it through their bony snout with a rapid snap of the head.

Life history

In seahorses, the female uses her ovipositor to deposit her eggs in the male's brood pouch where they are fertilized and remain until hatched. After a period of time, varying from ten days to six weeks, depending on the species and water temperature, the male gives birth to hundreds of live, tiny, seahorses, which are miniature replicas of the adults. Mode: dioecism, fertilization: in brood pouch or similar structure, and gestation period is 14–15 days depending on temperature.

Sources

• Project Seahorse 2003. Hippocampus ingens. 2006 IUCN Red List of Threatened Species. Downloaded on 4 August 2007.
• Underwater Photography Guide Pacific Seahorse found in California
• MarineBio Pacific Seahorses, Hippocampus ingens

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