NANFA-- Mass Extinction of Freshwater Creatures Forecast

Jay DeLong (
Mon, 1 Nov 1999 20:54:15 -0800

Of possible interest.

Jay DeLong
Olympia, WA

Mass Extinction of Freshwater Creatures Forecast

HALIFAX, Nova Scotia, Canada, October 4, 1999 (ENS) - The first Estimate of
extinction rates of North America's freshwater animals, just released, has
found they are the most endangered species group on the continent.

The Canadian study warns that the U.S. could lose most of its Freshwater
species in the next century if steps are not taken to protect them. "A
silent mass extinction is occurring in our lakes and rivers," says author
Anthony Ricciardi of Dalhousie University in Halifax. Ricciardi's study with
coauthor Joseph Rasmussen of McGill University in Montreal is published in
the October issue of "Conservation Biology."

Relatively little media attention has been given to freshwater species, the
authors say, but these animals are in at least as much danger as land
species. Since 1900, at least 123 freshwater animal species have been
recorded as extinct in North America. Common freshwater species, from snails
to fish to amphibians, are dying out five times faster than land species,
and three times faster than coastal marine mammals, the researchers found.

Their estimate of the loss of freshwater biodiversity "is probably
conservative," the researchers say, "because there have likely been
extinctions of species that we did not know existed, as suggested by the
fact that several extinct fishes are known from only a few specimens."

Freshwater animals are dying out as fast as rainforest species, considered
by many to be the most imperiled on Earth. The authors predict that about
four percent of freshwater species will be lost each decade if nothing is
done to conserve them. Worldwide the situation is even more perilous for
these creatures. The World Wide Fund for Nature (WWF) said in September that
51 percent of freshwater species, from fish and frogs to river dolphins, are
declining in numbers. The 1999 Living Planet Report, an annual index on the
state of the world's natural wealth, presents the most reliable data
available on forest area and populations of marine and freshwater species
worldwide. It also examines consumption of critical resources in 151
countries and its consequences. "This report is a graphic call to reduce
these negative trends as the world enters the 21st century," said Claude
Martin, director general of WWF. "The observed declines in populations of
freshwater species is particularly alarming as they indicate the extent of
deterioration in the quality of the world's rivers,lakes and other

Freshwater amphibians are hard hit. The disappearance of the golden toad and
other amphibians in Costa Rica has been attributed to climatic changes. Many
losses have been recorded in national parks and nature reserves, indicating
pervasive threats even in protected areas. In Australia, Panama and the US,
about 20 frog species have been decimated by a previously unknown fungus.
Deformities are also widespread, caused by pollutants such as pesticides and
other factors. The report, produced by WWF in collaboration with the New
Economic Foundation and the World Conservation Monitoring Centre (IUCN),
found that the total of marine and inland fish caught reached a record level
of 95 million tonnes in 1996, up 11 million tonnes from the annual average
in the preceding five years. To get a picture of how rapidly species
extinction is accelerating, the Canadian researchers compared current
extinction rates with those from the fossil record. They calculate that the
background rate of extinction for freshwater fish species is about one
species every three million years.

The modern extinction rate in North America, the study says, is about one
extinction every 2,600 years - about 1,000 times higher than the background
rate. Ricciardi and Rasmussen predict that many species considered at risk
will disappear within the next century. At risk species account for 49
percent of the 262 remaining mussel species, 33 percent of the 336 crayfish
species, 26 percent of the 243 amphibian species, and 21 percent of the
1,021 fish species.

Non-native species pose a serious threat to indigenous freshwater animals.
European zebra mussels are outcompeting native mussels in North American
lakes and rivers. Sea lampreys invade lakes and attach themselves to native
fish, killing them. Even sport fish transplanted from one lake to another
can take over an ecosystem, driving less aggressive native fish toward

Dams that obstruct river flow are also threats. Of 5.2 million kilometers
(3.2 million miles) of stream habitat in the lower 48 states, less than two
percent, or about 100,000 kilometers, is pristine enough to be federally
protected, Ricciardi and Rasmussen say. Excess sediment, toxic contaminants
and organic pollutants from agriculture threaten most U.S. waterways. Only
40 rivers longer than 200 kilometers (125 miles) remain free flowing in the
lower 48 states. "Such massive habitat deterioration threatens some of the
world's richest freshwater faunal assemblages," the study says. Ricciardi
and Rasmussen note that hundreds of U.S. dams are coming up for federal
relicensing soon, providing an opportunity to reestablish natural flows in
many rivers.

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