Nothing like spending a day out on the lake and coming home with a cooler full of fresh fish for dinner.

Just don't overdo it.

Like some fish you buy at the grocery store, certain types of fish you catch in the wild can have methylmercury in their tissues. Methymercury is a toxin that even in low doses is dangerous for children and some women.

In general, Wyoming's fish are low in mercury, but in December state agencies issued a health advisory telling anglers to be cautious about eating fish caught in Pathfinder, Seminoe and Big Horn reservoirs.

"We always watch it and I see it all across the country," said Rob Davis of Casper, a professional walleye fisherman and president of the Wyoming Walleye Circuit. "I think that's something that's been in Pathfinder and Seminoe reservoirs for a long time."

Mercury-fish advisories have been issued in every state except Alaska. Wyoming was the last of the Lower 48 states to issue one.

The state released the advisory based on recent studies that indicated methylmercury is more toxic than previously thought - not because there has been an increase in mercury levels in Wyoming's lakes, said officials from the Wyoming Department of Health and Wyoming Department of Game and Fish.

Studies show that even small amounts of methylmercury can have adverse effects on the developing nervous system of a fetus resulting in the child having a lower IQ, abnormal muscle tone and slow motor function. High doses can affect the nervous system of any adult causing problems such as memory loss and slurred speech. It can also damage kidneys and intestines.

The state's health advisory says that women of child-bearing age, pregnant women, nursing mothers and children under the age of 15 should not eat channel catfish, sauger or walleye from Pathfinder, Seminoe and Big Horn reservoirs. Other people should eat no more than one to two meals per month of fish caught from those three lakes.

To be on the safe side, all anglers should be aware of the size and species of fish they consume:

* Throw back the big ones:

* Watch out for predatory fish and bottom feeders:

According to the Wyoming Department of Health, swimming in bodies of water where mercury is present is not considered a health risk. Contact with the water, or the accidental swallowing of it, will result in minimal exposure to methylmercury.

The state is monitoring Wyoming's fish and will issue more advisories if needed. And as more testing is done, the state plans to categorize each specific species of fish for mercury risk.

Fish that eat other fish and ones that feed mostly on the bottom of lakes are more likely to accumulate mercury - species such as catfish, walleye, sauger and bass.A large fish is more likely to have high mercury levels than a smaller fish because the longer a fish lives the greater its chances are of accumulating mercury in its tissues. So eat more small fish and fewer large fish.