The mysterious Altamaha spinymussel is becoming the latest Middle Georgia addition to the endangered species list.
Like a fisherman, the mussel uses a lure to attract an unknown host fish to carry its larvae. The spiky-shelled mussel looks like a projectile and is believed to eat with its foot during a portion of its life cycle.
“The one thing we can say about them definitively is there’s darn few of them,” said Jimmy Rickard, a biologist for the U.S. Fish and Wildlife Service, which decides endangered species listings.
The Endangered Species Act makes it illegal to kill or harm a listed species and directs federal wildlife officials to help it recover.
The Altamaha spinymussel is found in the lower stretches of the Ocmulgee River and in the Altamaha River, but it has disappeared from the Oconee and Ohoopee rivers.
The Fish and Wildlife Service is designating critical habitat along the upper Altamaha, lower Ocmulgee and Ohoopee rivers in Appling, Ben Hill, Coffee, Jeff Davis, Long, Montgomery, Tattnall, Telfair, Toombs, Wayne and Wheeler counties.
Critical habitat is an area that receives special protections to provide an endangered species a place to live. Wildlife regulators must be consulted to be sure any project that uses federal dollars or requires federal permits does not harm the habitat.
Rickard said the Fish and Wildlife Service estimated the critical habitat would have an economic impact of about $37,100 over 30 years, mostly to the power generation sector.
The critical habitat portion of the Endangered Species Act was rarely used until the last decade or so, when environmental groups began suing the federal government to enforce the law.
In this case, the Altamaha spinymussel gets its endangered designation partly as the result of a legal settlement between the Fish and Wildlife Service and the Center for Biological Diversity. The center had sued to speed up endangered species designations and other protections for 757 species across the country, according to a news release from the center.
According to the Center for Biological Diversity, freshwater mussels are the most imperiled group of organisms in the United States. This is partly because they filter algae, bacteria and decaying matter from water. This makes mussels helpful in cleaning the water supply, but also very susceptible to pollution.
Mussels reproduce with the help of host fish. Adult mussels make a lure that looks like a young fish or worm, which attracts feeding fish. The mussel releases its fertilized eggs onto the fish’s gills, and young mussels develop there before dropping off, all apparently without harming the fish.
In recent years, a biologist at the Tennessee Aquarium in Chattanooga, Tenn., tried unsuccessfully to identify the spinymussel’s host fish, and another such effort has been under way at the University of Georgia for several years, Rickard said.
Rickard said biologists have spent about 1,000 hours since 1997 searching rivers for Altamaha spinymussels, finding only about 60 of them. (In the 1960s, as many as 60 were found in a single bed, he said.)
Rickard said it’s hard for scientists to figure out how to save the mussel when they know so little about its life cycle. The leading theory is that the mussel’s host fish has become rare, perhaps because flathead catfish introduced to the river system have eaten most of the host fish. But the state’s effort to kill catfish by shocking them in the water didn’t work.
Rickard said the mussel also might be suffering because of changes in river bottom sediments, pollution from wastewater effluent or heavy metals contamination. According to a Fish and Wildlife Service news release, listing of the spinymussel as endangered becomes effective Nov. 11, 30 days after the rule’s publication in the Federal Register.
To contact writer S. Heather Duncan, call 744-4225.