Species: E. naucrates
Echeneis naucrates has modified dorsal fin used as a sucking disc to attach to hosts makes the sharksucker easy to distinguish from other fish. This oval-shaped sucking disc consists of 16-28 laminae and is positioned from the top of the head to the anterior portion of the body. The sharksucker has a long slim body, measuring 11 or 12 times as long as it is wide. The lower jaw of the sharksucker projects forward beyond the upper jaw. The dorsal fin and anal fin originate at the midlength of the body and taper, extending almost to the base of the caudal fin. The caudal fin of mature specimens is almost truncate with the upper and lower lobes longer than the middle rays. The pectoral fins are located high on the sides of the body with upper margins overlapping the edge of the sucking disc. The dorsal and anal fins have long bases with elevated leading rays. It is difficult to distinguish male and female specimens. The young begin to resemble the adults upon the formation of the sucking disc.
Although known for attaching to a variety of hosts including sharks, rays, large bony fishes, sea turtles and marine mammals as well as sometimes ships, the sharksucker is often observed in free-swimming groups over shallow coral reefs. This species is dependent upon their hosts for survival as they are a poor swimmer and lack a swim bladder. It attaches to the host beginning early in their lives with a modified dorsal fin that is used as a sucking disc. Sharksuckers typically attach themselves onto either the body or the gill region of the host. There have been documented sightings of sharksuckers traveling up freshwater rivers while attached to a host.
The sharksucker attaches to a variety of hosts including sharks, rays, large bony fishes, sea turtles, whale, dolphin, and even sometimes to ships. During this time of attachment, the sharksucker feeds on food scraps from the host’s feeding activities as well as small crustaceans parasites on the host’s skin. This diet is supplemented with free-living crustaceans, crabs, squid, and small fishes. Juvenile sharksuckers sometimes act as cleaning fish, setting up cleaning stations where they clean parasites off parrotfishes. In captivity, the sharksucker can be feed pieces of clam and fish by hand.
Spawning occurs during the spring and summer months throughout most of its range and during the autumn months in the Mediterranean Sea. The eggs are fertilized externally followed by enclosure of a hard shell, which protects them from damage and desiccation. These pelagic eggs are large and spherical in shape. When the embryos hatch, each measures 0.18-0.30 inches (.47-.75 cm) in length. These young fish have a large yolk sac, non-pigmented eyes, and an incompletely developed body. During development of the newly hatched fish, the sucking disc begins to form. Small teeth appear on the upper jaw and large teeth on the lower jaw during this period. Immature sharksuckers live freely for about one year until reaching approximately 1.2 inches (3 cm) in length at which time they attack to a host fish.
Habitat and Distribution
This fish is the most abundant remora and is found in inshore as well as offshore in tropical and warm temperate waters at depths from 66-164 feet (20-50 m). This unusual fish has a wide distribution range including the Pacific Ocean north to San Francisco, California and in the Indian Ocean. It is also commonly observed from southwestern Western Australia and around the tropical north and south to the southern coast of New South Wales. It is less often observed in waters off Victoria and Tasmania. In the western Atlantic Ocean, the sharksucker is found from Nova Scotia, Canada east to Bermuda and south to Uruguay.