Organism Movement–
Other Aquatic Vertebrates

There are a number of relatively large aquatic animals that inhabit streams and rivers but are rarely considered in terms of barriers to movement. Much of the U.S. supports large species of aquatic salamanders (species that rarely or never venture forth on land). Mudpuppies, waterdogs, hellbenders, sirens, and amphiumas are salamanders that are fully aquatic and range in adult size from about a foot to over three feet in length. The Oklahoma salamander and the Pacific giant salamanders of the west coast are other aquatic salamanders that are vulnerable to movement barriers.

Significant portions of the U.S. support softshell and musk turtles, aquatic reptiles that rarely travel overland. Movements of spiny softshell turtles are almost exclusively aquatic (with the exception of nesting and basking). In Arkansas , these turtles moved on 85 percent of the days they were tracked with average daily movements of 403 - 465 ft/day. Some individuals moved more than 2,970 ft/day. Annual home range length for these animals averaged between 4,620 and 5,775 ft (Plummer, et al. 1997. Chelonian Conservation and Biology. 2(4):514-520).

Little is known about the swimming abilities of amphibians and reptiles but it is believed that they are not strong swimmers (relative to migratory fish). Many species may rely more on crawling than swimming. Yet movement and population continuity is essential to the survival of their populations. When moving upstream aquatic amphibians and turtles probably seek out lower velocity sections of streams and take advantage of boundary layers (low-velocity zones) along the stream bottom and bank edges. Some salamanders may require relatively continuous cover on the stream bottom, moving from rock to rock in order to reduce exposure to predators or high velocities.