U.S. Fish & Wildlife Service Caribbean River Fish

Description The American eel is a very active Native fish that move far up the river predator, but has weak eyes and a well systems are described here including developed sense of smell, thus preferring species from the families of mullets, to hunt at night. sleepers, eels, and gobies. Related species with similar life cycles occur in Little is known of the habits of the river rivers on tropical and sub-tropical goby, but it is often seen moving along oceanic islands. the bottom looking for small prey in the crevices or sediments. Habitat and Life Cycles Caribbean freshwater fish dominate the The Sirajo goby scrapes algae off rocks lower river systems, although some in the streams. It is capable of moving up vertical surfaces with the sucker formed L.Miranda occur in steep mountain streams. Some American eel (Anguilla rostrata) of the species mature and reproduce in from its modified ventral fins. With this the rivers, but the larvae move sucker, it can move up vertical wet downstream to estuarine or marine surfaces. The larvae of this goby are waters, and juveniles must migrate back fished by the thousands as they migrate upstream. back into the rivers, and they are relished as a local delicacy. The American eel, has a reverse life cycle where the females mature in the Threats and Conservation Measures rivers, and move far out to sea to spawn. River fish can be impacted by a variety Larvae make their way to the of human activities such as projects that continental and island coasts where they modify stream channels or flow, and migrate back up the rivers. deliberate or accidental discharge of

B. Yoshioka toxic substances into the rivers. mountain mullet (Agonostomous The big-mouth sleeper, is known to be able Dams, water intakes, or river monticola) to complete its life cycle in freshwater channelization affect most of these lakes, but may also utilize the estuaries. species because of their complex life cycles. In the continental U.S., the The larger fish generally inhabit the American eel is considered to be a deeper pools or runs in streams, while species of concern because of the small species like the Sirajo goby move elimination of much of its historic river to the highest parts of the river system. habitat due to dam construction.

J. Holmquist Distribution There are many ways that the design or river goby (Awaous tajasica) These species are widespread in the operation of needed projects can be Caribbean on island and continental modified to reduce impacts. Maintaining coasts. Most are tropical or sub-tropical reasonable minimum river flows, with very limited occurrences on the reducing obstructions to migration, and U.S. gulf coast. They are assumed to be maintaining habitat variety should all the same species across their ranges, be considered. because of their appearance and since the larvae can travel between islands. Education on the careful use of B. Yoshioka agricultural chemicals, and strict Sirajo goby (Sicydium plumieri) Ecology enforcement against the use of The Caribbean river fish include chemicals for fishing are critical for predators, omnivores, and herbivores. maintaining water quality of aquatic life Most of the large predatory fish have and human use. limited abilities to move up steep streams, but are abundant in pools at The health of aquatic communities lower elevations. may be the best indicator of stream water quality for human use. We still The mountain mullet is omnivorous, but have much to learn about these feeds actively on small shrimps and interesting organisms. insects, often near the water surface. It is fished for food and sport. The big- For more information, please contact: mouth sleeper reaches large sizes, is U.S. Fish and Wildlife Service

B. Yoshioka exclusively predatory, and is a popular Boquerón Field Office big-mouth sleeper gamefish. Both fish rely primarily on PO Box 491, Boquerón, PR 00622 (Gobiomorus dormitor) sight to locate prey. Telephone: 787/851 7297