The United States Fish and Wildlife Service has published a proposed rule to designate critical habitat for the Big Sandy crayfish (Cambarus callainus) and the Guyandotte River crayfish (Cambarus veteranus).
The Big Sandy crayfish is federally listed as a threatened species and currently lives in specific watersheds of Virginia, West Virginia, and Kentucky. The Guyandotte River crayfish is federally listed as an endangered species and currently lives in specific portions of two streams in West Virginia.
The critical habitat rule proposes to designate a total of 362 stream miles as occupied critical habitat for the Big Sandy crayfish in Kentucky, Virginia and West Virginia. These streams are located in Martin and Pike counties, Kentucky; Buchanan, Dickenson, and Wise counties, Virginia; and McDowell, Mingo, and Wayne counties, West Virginia. For the Guyandotte River crayfish, the critical habitat rule also proposes to designate approximately 41 stream miles as occupied critical habitat in Wyoming County, West Virginia, and 42 stream miles as unoccupied critical habitat in Logan County, West Virginia.
Because the Big Sandy Crayfish and the Guyandotte Crayfish are protected under the Endangered Species Act, it would already be unlawful to kill them with or without this designation. This designation of critical habitat would mean that a federal agency may not undertake, fund, or allow activity that would destroy or adversely modify critical habitat. If, for example, if a proposed mine or other activity were in the vicinity of a critical habitat, any agency considering issuing a permit would have to avoid adversely modifying the habitat. When faced with possible habitat destruction, the agency involved would be required to consult the Fish and Wildlife Service about the actions they are considering carrying out, funding, or authorizing.
Crayfish are an extremely important component of aquatic ecosystems, in Appalachia and worldwide. They eat and get eaten. They eat smaller plants and animals, keeping streams and wetlands clean and harboring balanced populations. They sustain Hellbenders, raccoons, otters, Great-blue Herons, and, most importantly to fisher folk among us—smallmouth bass. Their creation of “chimneys” and tunnels, terrestrial and aquatic, is critical to survival of a very large number of invertebrates, as well as rodents, snakes, and frogs; so crayfish are a “keystone” species. They’re also sensitive to environmental impacts, so their numbers are a good indication of the health of a waterway.
Researchers have only known of these species since the early to mid 20th century. At that time, the upper Big Sandy River and Upper Guyandotte River watersheds were undergoing rapid and widespread changes caused by industrial scale forestry and coal mining. The erosion and sedimentation associated with these activities degraded the streams in the region and made most of them unsuitable for the crayfishes.
Scientific evidence indicates that the Big Sandy crayfish once occurred in streams throughout the upper Big Sandy River basin in Kentucky, Virginia and West Virginia. Likewise, the Guyandotte River crayfish occurred in streams throughout the Upper Guyandotte River basin in West Virginia. Today, the Big Sandy crayfish is found in six isolated populations across Floyd and Pike counties, Kentucky; Buchanan, Dickenson, and Wise counties, Virginia; and McDowell and Mingo counties, West Virginia. The Guyandotte River crayfish is found in only two streams in Wyoming County, West Virginia.
While the intensity of coal mining and forestry has dropped from the historical highs of the 20th century, active coal mining and commercial timber harvesting are still ongoing in the region and contribute to sedimentation in the streams and rivers. Other activities, such as natural gas development, highway construction, and ORV use, are increasing and can further degrade stream habitat. Additionally, the small, isolated nature of the populations of both species inhibits gene flow, making them even more vulnerable to extirpation. A single event like a contaminant spill could potentially eliminate an entire population.
At about 3 to 4 inches long, both crayfishes live beneath loose, large boulders in fast flowing streams and rivers. With their olive brown to light green coloring, they blend in well with the stream bottom. They live an average 5 to 7 years, and because they don’t reproduce until 3 to 4 years of age, their populations can take a long time to rebound.
The rule is not yet final. The public can comment on the proposed rule until March 30, 2020. Also available is a proposed Draft Economic Analysis of the proposed designation of critical habitat.