Seahorses Sticklebacks and Relatives: Gasterosteiformes

Physical characteristics: The belly of lined seahorses faces forward rather than down. The head is at a right angle to the trunk and tail. The snout is long, and the mouth has no teeth. There are pairs of spines behind the eyes. There is one dorsal fin just in front of the tail. The pectoral and anal (AY-nuhl) fins are small, and there are no pelvic fins. The anal fin is the one along the midline of the belly. The grasping tail tapers into a slender stalk without a tail fin. The body is encased in ten to twelve bony rings, each with four spines. The tail has about thirty-five rings. The color can be light brown, black, gray, yellow, or red covered with small blotches, stripes, and spots. Small white

The eggs develop in the male lined seahorse's pouch for twelve to fourteen days. The young seahorses look like tiny adults when they are born. (©Gregory G. Dimijian/Photo Researchers, Inc. Reproduced by permission.)

stripes extend from the eyes. Lined seahorses grow to a length of about 8 inches (20 centimeters).

Geographic range: Lined seahorses live in the western part of the Atlantic Ocean.

Habitat: Lined seahorses live in shallow waters and waters as deep as 240 feet (73 meters). They live in bays, near beaches, in salt marshes, in oyster beds, around piers, and in other environments with plants and shelter. They can withstand great variations in temperature and salt content.

Diet: Lined seahorses eat small crustaceans (krus-TAY-shuns) and larvae. Crustaceans are water-dwelling animals that have jointed legs and a hard shell but no backbone.

Behavior and reproduction: Lined seahorses swim slowly, belly forward, by making wavelike movements of the dorsal and pectoral fins. They use their tails to cling to plants and coral. These fish produce sounds to communicate with one another. Younger lined seahorses live in open water, sometimes swimming in groups.

After courting, male and female lined seahorses meet belly to belly and twine their tails together. The female then transfers her eggs to the male a few at a time until there are 250 to 400 eggs in his pouch. As eggs are being transferred, both seahorses rise in the water and may change color. The eggs develop in the pouch for twelve to fourteen days. The young seahorses look like tiny adults when they are born.

Lined seahorses and people: Lined seahorses are common in aquariums.

Conservation status: The IUCN lists lined seahorses as Vulnerable or facing a high risk of extinction in the wild. ∎