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Agencies advise limited consumption of some fish species below mill site on Clark Fork

Published On: Dec 24 2013 09:45:48 AM MST   Updated On: Oct 17 2013 10:11:20 PM MDT

Important information for Montana fishers -- biologists issued what's called a “fish consumption advisory for two Montana fish -- rainbow trout and northern pike.

Montana Fish, Wildlife and Parks biologists tell NBC Montana they are focused on a 105-mile stretch of the Clark Fork River. The advisory area starts where the Bitterroot and Clark Fork Rivers meet near Missoula and ends where the Clark Fork meets the Flathead River near Paradise.

Biologists tell us it’s that stretch of river where both species of fish tested for high levels of contaminants.

We’re told the old Smurfit-Stone Mill site is the cause of the contamination of northern pike and rainbow trout.

Biologists tell NBC Montana that people should not eat any northern pike they catch on this stretch of river.  They say rainbow trout are still OK to eat but people need to limit themselves to only four a month.

Missoula angler Jason Looney says with Montana's history of mining and milling many fishermen are already in the habit of releasing the fish they catch.

"Were just starting to kind of take into consideration environmental factors like toxicity and groundwater and whatnot like that so its definitely something that area wide it's going to get a little bit worse before it gets better," says Looney.  "There's a lot of stuff that needs to leach out of these areas I would say."

The contaminants in the fish have been linked to birth defects and nervous system and immune system problems according to FWP officials. 

They say if you've eaten fish from the river lately, don't panic because it takes a high level of contaminants to hurt a human. However if you fancy a good rainbow trout dinner biologists say there are steps you can take to ensure your meal is safe.

“When we looked at the contaminant levels we looked at them in just the fish coming straight out of the river,” says FWP biologist Vivica Crowser.  “If you're cooking the filets and taking the fat out you're really reducing a lot of the accumulation of contaminants so getting rid of that fat and cooking the meat will reduce it and that's really the best way to handle and to eat fish.”

Biologists tell us they have not run contamination tests on any other species of fish on this stretch of the Clark Fork River besides the northern pike and rainbow trout.

Crowser says northern pike and rainbow trout were tested because they're two of the larger fish found in the Clark Fork River.


The following is a press release from Montana FWP:

Three state agencies today issued fish consumption advisories for northern pike and rainbow trout on a 105-mile stretch of the Clark Fork River in western Montana.

A "do not eat" advisory was issued for northern pike, and a "four meal per month" limit for rainbow trout, from the Clark Fork's confluence with the Bitterroot River, near Missoula, to the confluence with the Flathead River, near Paradise.

The advisories were issued by the Montana departments of Fish, Wildlife & Parks, Environmental Quality and Public Health and Human Services in response to contaminant investigations in fish immediately downstream of the Smurfit Stone Container mill site in Frenchtown.

Research this summer by FWP turned up dioxins, furans, and polychlorinated biphenyls, or PCBs—contaminants commonly associated with the pulp and paper mill industry—in northern pike and rainbow trout taken from the river.

Other species of fish from the Clark Fork River haven't been studied at this time.

At very high levels of exposure, these contaminants have been linked to adverse human health effects in immune and nervous systems and may be associated with birth defects. Dioxin and PCBs are classified as definite and probable human carcinogens, respectively, at high and prolonged levels of exposure. Fish consumption advisories are designed to keep exposures well below these high levels. The actual health risks to anyone who has been eating fish in this area is very low, state health officials said.

Northern pike had potentially dangerous levels of the three chemicals. Rainbow trout had lower levels of the same contaminants. Levels are higher in northern pike because they live longer, grow larger, and eat other fish.

Fish consumption advisories are conservative and designed to protect the most sensitive members of the population over a lifetime.  In addition, the risks are based on the amount of toxins found in a raw fillet. Using normal cooking practices, and keeping only smaller fish, can reduce exposure risks.

When properly prepared, fish provide a diet high in protein and low in saturated fats and may be helpful in preventing heart disease. These preparation guidelines can optimize health benefits:

  • fillet the fish
  • remove the skin
  • cut away dark fatty tissue from the back and belly of the fish where harmful chemicals tend to accumulate
  • bake or broil the trimmed fish on a rack or grill it so the remaining fat drips away