Where do seahorses live and what do they eat?

March 7, 2005

These unusual animals can be found around the world. They live among coral reefs, mangroves and beds of sea grass and sea weed in shallow, tropical and temperate waters. In North Carolina, we have the lined seahorse, Hippocampus erectus.

During breeding season, seahorses form pair bonds and mate with only one other individual. Several species perform elaborate courtship dances.

Seahorses belong to the Syngnathidae family of bony fish and are poor swimmers. They don’t move around much. Instead, they establish small territories and use their grasping, prehensile tail to anchor themselves to objects. Males will often spend several days on the same blade of grass or piece of coral.

Seahorses feed on small crustaceans, such as shrimp. Their small mouth is at the end of their long tubular snout. They don’t have teeth or a stomach, so they use their snout like a vacuum to suck up tiny animals. Without stomachs they can’t digest food efficiently and must eat enormous amounts. A young seahorse can consume up to 3,000 baby brine shrimp in 10 hours!

Seahorses can move their eyes independently, enabling them to track prey with one eye and watch for predators with the other. When threatened, they hold tightly to a blade of grass or piece of coral and pull their heads in close to their chests.

Another interesting thing about seahorses is that they mate for life and the male carries and gives birth to the young. The female produces eggs, but the male carries them in his stomach pouch until they hatch. The father labors a day or more before being able to force the live young from the pouch. Depending on the type of seahorse, the brood size ranges from 15 to 1,000 young. Newborns are a quarter-to a-half-inch long and are exact replicas of their parents. They are fully independent from birth. In the wild, fewer than 5 of 1,000 young survive to adulthood.

Adult seahorses have few predators, however remains have been found in crabs, tuna, skates and rays. Storms also pose a threat to these small, weak swimmers. Heavy surf can tear them from their holdfasts and cast them on shore, or carry them out to sea where they are unable to swim to safety.

Over the years, more than 100 species of seahorse have been described, but currently only about 32 are recognized be researchers. Unfortunately, seahorse populations are declining. There appear to be several reasons for this: Seahorses are heavily harvested for use in traditional medicines, home aquaria and as curios and souvenirs. More than 20 million seahorses are sold each year for traditional Chinese medicine.

Humans also threaten seahorse survival by damaging habitats. As people move to coastal areas in ever-greater numbers, sediment from construction and agriculture, nutrients from lawns and farms, and chemicals from a wide variety of sources all end up in coastal waters. This can seriously disrupt the natural processes of coastal habitats where seahorses and other animals live.