Fish Consumption Advisory Issued for Noxon Rapids Reservoir
April 8, 2005
The Montana Department of Public Health and Human Services (DPHHS) has issued an advisory recommending that people limit their consumption of certain species of fish taken from the Noxon Rapids Reservoir near Thompson Falls. Recent sampling of the fish by state Fish, Wildlife, and Parks (FWP) biologists has found that they contain elevated levels of mercury, which can adversely affect human health.
The advisory applies to northern pike, smallmouth bass, yellow perch, and lake whitefish. FWP will post signs at fishing access sites on the reservoir to alert people to the consumption advice. Consumption of other fish species in Noxon Rapids Reservoir is not restricted at this time.
“Women of child-bearing age, pregnant women, nursing mothers, and young children are the most sensitive to mercury because of the effect the metal can have on developing nervous systems,” said Howard Reid, with the Food and Consumer Safety section of DPHHS. “Women who are past child-bearing age and adult men are less sensitive to mercury and can safely eat more of these fish.”
DPHHS advised that fish from the reservoir can be consumed safely as shown below:
Fish species |
Mercury level |
Adults & children 7-18 |
Women of child-bearing age & children 6 & under |
Large pike (>27”) |
0.91 ppm |
4 meals per month |
1 meal per month |
Small pike (<27”) |
0.34 |
8 |
3 |
Smallmouth bass |
0.66 |
4 |
1 |
Yellow perch |
0.52 |
5 |
2 |
Lake whitefish |
0.15 |
No restriction |
7 |
Under DPHHS guidelines, levels of more than 0.10 parts per million trigger consumption advisories for high-risk individuals.
“These guidelines aren’t meant to discourage people from fishing at Noxon Rapids Reservoir or from eating fish,” Reid said. “They’re simply meant to help people make healthy choices about the way they include fish in their diets.”
Reid said the source of the mercury is unknown.
“It could be from old mining activity or from incineration activity, or it may just be naturally occurring,” he added. “Some soils in Montana are naturally high in mercury.”
FWP biologists tested Montana fish for mercury for the first time last fall after the U.S. Environmental Protection Agency (EPA) offered to perform laboratory analyses of fish samples at no charge. EPA has so far analyzed 118 samples from water bodies across the state
Since 1994, DPHHS and FWP have worked in partnership with the EPA to sample sport-caught fish and develop and publish fish consumption guidelines for use by Montana anglers. Current guidelines are available at all FWP offices, through fishing license providers, and online at 2005 Sport Fish Consumption Guidelines.
For more information, contact DPHHS at (406) 444-5306 or FWP at (406) 444-5686.
Page last updated: 06/14/2006
