August 8, 2005
Invasive fish species threatens native fauna
U.S. Geological Survey fisheries biologists in Gainesville, Fla., have
confirmed the presence of the voracious non-native northern snakehead fish
in Meadow Lake in Queens, N.Y. Five specimens have been collected by the
New York State Department of Environmental Conservation from the lake in
Flushing Meadows Corona Park since early July. In the last 5 years, these
adept predatory fish have been found in rivers and ponds in Florida,
Maryland, Massachusetts, Pennsylvania and Virginia, threatening the
well-being of native aquatic species.
The northern snakehead is an air-breathing, freshwater fish native to
waters ranging from southern Siberia to south-central China. This species
is highly valued as a food fish in its native range, and was exported to
the United States for live sale in some markets and restaurants before
Juvenile and adult snakeheads feed almost exclusively on other fishes
(90-95 percent of their diet). Northern snakeheads also protect their young
through the post-larval stage, which further encourages the establishment
of a feral snakehead population. Fisheries biologists consider the
snakehead an invasive species because of the threat they pose to native
species and aquatic ecosystems.
At present, researchers have not determined if the Meadow Lake population
is established as a reproducing population. According to USGS fisheries
biologist Walter Courtenay, however, the range in length of the collected
specimens from 15 to 28 inches suggests the presence of two distinct year
age groups of snakeheads in Meadow Lake.
A comprehensive snakehead fish study, including a biological synopsis, risk
assessment, and accounts for each species, was conducted from September
2001 to September 2002 by the U.S. Geological Survey and the U.S. Fish and
Wildlife Service. The entire report can be accessed online by visiting the
USGS Web site.