Facts: The Spotted Handfish

The spotted handfish is a curious-looking anglerfish species that is currently at high risk for extinction. This fish is known only from a single place in the world, the cool, temperate coastal waters of the Derwent River estuary in Tasmania. This estuary is an urbanized, polluted, and disturbed system. The handfish were once common here, but between the 1980s and 1990s, spotted handfish experienced significant population declines. Now, they are critically endangered, with an estimated fewer than 3,000 individuals remaining. Spotted handfish inhabit the brackish water that separates river from sea, from 3 to 200 ft deep. Their body is covered with spots and stripes. Their pectoral fins are modified so that they look like little hands that they use to perch on the seafloor or to slowly clamber about on the seabed. They mainly use their modified fins to travel instead of swimming since they possess no swim bladder to maintain their buoyancy. Like other anglerfish, spotted handfish have a fleshy growth sticking out of their head that acts like a lure to catch food. Handfish like to eat worms and crustaceans from the sandy seafloor. Spotted handfish lay a small number of eggs on the seafloor, typically between 60 and 250 eggs. The eggs may be laid around the base of sea squirts, sea grasses, or sponges. The female guards the eggs for 7 to 8 weeks until they hatch into fully formed juveniles. Their lack of a planktonic larval phase contributes to their narrow range and limited dispersal. They grow to around 5 in in length. Their primary threat is egg predation by the northern Pacific sea star. The sea star is not native and was likely introduced by ship ballast water. Since the sea stars are not natural predators of handfish eggs, the handfish populations quickly started to fall after their introduction. Trawling, dredging pollution, and other activities that could disturb handfish habitat are also threats. For more marine facts, click the SUBSCRIBE button!!