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posted on December 01, 2009 10:11


Idaho Lifts Fish Consumption Advisory for Silver Creek Watershed
A fish consumption advisory for elevated mercury levels in the Silver Creek watershed in south-central Idaho near Picabo is being lifted due to the discovery of a calculation error by an analytical lab.
The Silver Creek fish consumption advisory was recommended in 2007 following sampling of fish by the United States Geological Survey (USGS) and subsequent analysis of fish tissue samples conducted by an out-of-state lab. The fish advisory recommended that people limit the amount of brown trout they ate from the Silver Creek watershed.
USGS staff in Boise noticed the problem when they recently reviewed testing results that showed a large drop in the mercury level of fish compared to levels found two years ago. This led the USGS researchers to contact the lab since mercury levels in fish tend to be fairly constant from year-to-year. The lab reviewed their 2007 report and found that a calculation error had overestimated the levels of mercury in fish. USGS notified Idaho officials of the error and provided corrected results.
“This is one of Idaho’s premier sport fisheries and is good news for the Silver Creek watershed,” says Jim Vannoy, Environmental Health Program Manager who oversees the Idaho Fish Advisory Program for the Department of Health and Welfare. “It was an unfortunate error, but the lab has assured us that they have implemented procedures to prevent this from happening again.”
As a safeguard, Idaho Fish and Game resampled fish from Silver Creek last week, with the Idaho Bureau of Laboratories analyzing those samples. This recent sampling shows levels of mercury are below an advisory level and are similar to the recalculated levels provided from the 2007 sampling. The Idaho Fish Consumption Advisory Program also reviewed the other fish advisories in the state and found that all other advisories are supported by reliable data.
A fish advisory is issued when the level of contaminants in fish reach levels where the benefits of eating fish are outweighed by the risk to health. Mercury is the most common environmental contaminant absorbed by fish that can affect people, especially the developing nervous systems of young children and the fetuses of pregnant women. All 50 states have advisories for mercury in fish which provide information on the amount of fish that people can safely eat without worrying about possible health effects. 
With lifting of the advisory, the general public can consume fish from Silver Creek in areas where Idaho Fish and Game rules and regulations allow anglers to harvest rainbow trout or brown trout.  Please consult current Idaho Fish and Game regulations for details on fishing restrictions and bag limits. For information on other Idaho sites which have a fish consumption advisory please click here or visit
“Eating fish on a regular basis is beneficial for both children and adults,” Vannoy says. “Fish are a good source of protein, vitamins, and Omega 3 fatty acids which are crucial for the healthy development of children. The American Heart Association recommends that people eat 2-3 servings of low-mercury fish and seafood a week for both a healthy nervous system and a healthy heart. Our state’s fish advisory program wants people to enjoy fishing and the rewards of fishing, but to keep in mind that there are some areas with advisories and they may need to limit the amount they eat. We also like to recommend that people eat the smaller fish since they tend to have lower levels of contaminants in them.”
For more information about safe consumption of fish, mercury, or water issues please visit these websites:

Environmental Protection Agency:

U.S. Geological Survey Water-Quality Assessment Program:

 Idaho Fish and Game:

Idaho Department of Health and Welfare:

The Idaho Fish Consumption Advisory Committee is comprised of representatives from the Idaho Department of Health and Welfare, Idaho Department of Environmental Quality, Idaho Department of Agriculture, Idaho Fish and Game, U.S. Geological Survey and the U.S. Environmental Protection Agency.
(Editors: For additional information please contact DHW Environmental Health Program Manager Jim Vannoy at 208-334-4964.)