North American Freshwater Fishes Fading into Extinction

GAINESVILLE, Florida, September 9, 2008 (ENS) - Fishes that once were abundant in North American streams, rivers and lakes are now disappearing, with nearly 40 percent of all species in jeopardy, according to the most detailed assessment of the conservation status of freshwater fishes in the last 20 years.

The report shows that 61 fishes are presumed extinct, and 280 species are classed as endangered. In addition 190 are considered threatened, and 230 fishes are listed as vulnerable to extinction.

An endangered holiday darter from the southeastern United States (Photo by Noel Burkhead courtesy USGS)

The new report, published in the journal "Fisheries," was conducted by a team of scientists from the United States, Canada and Mexico, led by scientists from the U.S. Geological Survey. The team examined the status of continental freshwater fishes and those that migrate between rivers and oceans.

"Freshwater fish have continued to decline since the late 1970s, with the primary causes being habitat loss, dwindling range and introduction of non-native species," said Mark Myers, director of the USGS. "In addition, climate change may further affect these fish."

The 700 fishes now listed as imperiled for this report by the Endangered Species Committee of the American Fisheries Society are a 92 percent increase over the 364 listed in the previous 1989 study.

The fish at greatest risk are the salmon and trout of the Pacific Coast and western mountain regions. More than 60 percent of the salmon and trout had at least one population or subspecies in trouble, the report shows.

Also at great risk are minnows, suckers and catfishes throughout the continent; darters in the southeastern United States; and pupfish, livebearers, and goodeids, a large, native fish family in Mexico and the southwestern United States.

Fish families important for sport or commercial fisheries are also vulnerable to extinction. One of the most popular game species in the United States, striped bass, has populations on the list.

Twenty-two percent of sunfishes, a family which includes the well-known species such as black bass, bluegill and rock bass, are listed as at risk.

An endangered Alabama sturgeon from the Mobile River. (Photo courtesy Patrick O'Niel, North Carolina Department of Environment and Natural Resources)

The southeastern United States, the mid-Pacific coast, the lower Rio Grande and basins in Mexico that do not drain to the sea are losing their freshwater fish species more quickly than other regions...CONTINUE