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CENTER for BIOLOGICAL DIVERSITY Because life is good

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Native trout and amphibian populations are declining in California and throughout the West. Scientists have shown a direct link between nonnative fish stocking and these declines, which are devastating such species as the golden trout, Lahontan cutthroat trout, mountain yellow-legged frog, Yosemite toad, arroyo toad, and Cascades frog. Most native trout in California — nearly all of which are threatened by fish stocking — are listed as threatened or endangered under the Endangered Species Act, and a number of amphibians are listed as threatened or endangered or are candidates for listing in part because of fish stocking. Nonnative trout stocking may be the single biggest factor in the decline of native fish species in the Sierra Nevada.

Fish stocking creates several problems for California’s natural environment: Nonnative, stocked fish prey on and compete with native species for food and habitat, and stocked fish are altering the natural ecosystem to the detriment of native species; in addition, each and every time a lake or stream is stocked with nonnative fish, there’s a risk of spreading disease, exotic organisms, and unwanted fish.

The Center compared all water bodies stocked with trout in 2005 with the locations of imperiled native fish and amphibians, finding that nonnative trout were stocked in a minimum of 47 water bodies in California where rare species were present, affecting at least 39 different kinds of imperiled fish and amphibians. Our assessment likely underestimates the extent to which harmful stocking occurred and is the tip of the iceberg in terms of impacts of nonnative trout on California’s natural heritage. Many more species continue to be affected by fish that were stocked over the past 150 years.

Despite the serious declines of native fish and amphibians, the California Department of Fish and Game has refused to conduct an environmental review of its stocking practices. The Center’s Fish-stocking Reform campaign aims to protect existing quality habitat and healthy native fish and amphibian populations from further degradation, and to secure protection of high-quality watersheds from the threat of future stocking. We submitted comments in 2005 and 2006 requesting that California initiate an environmental review of its fish-stocking practices to alleviate the impacts on imperiled aquatic species. After no review was conducted, we took our case to court in 2006. In 2008, the Sacramento Superior Court ordered the state to consult with the Center and Pacific Rivers Council on ways to protect native species from fish-stocking impacts, and the California Department of Fish and Game agreed on measures to limit the environmental harm of its stocking program. But when Fish and Game released its final fish-stocking environmental impact report in 2010, it failed to analyze the full effects of stocking or take steps to protect native fish and amphibians — so in February 2010, we took the agency to court again.