There are few summer activities more enjoyable than catching your dinner from a local lake or stream, but families with young children might want to make it a special treat.
Some New Mexico fish have consistently tested positive for contaminants including mercury, PCBs and DDT, according to an annual advisory from the state Game and Fish, Environment and Health departments. Mercury is particularly harmful to the developing brains of fetuses, babies and children under six, and too much exposure can cause long-term health problems.
Older fish and predatory fish (such as walleye, bass or pike) typically carry larger amounts of mercury in their bodies. State Game and Fish Department Environmental Scientist Gary Schiffmiller said some amount of mercury is naturally occurring, and the rest comes from the smokestacks of coal-burning power plants, mining operations or other human activity.
PCBs are industrial chemicals that may cause cancer as well as damage to nerve development, reproduction and hormones. Although they were banned in the 1970s, Schiffmiller said they are extremely durable in the environment. They still exist in old electrical transformers, and they can still travel from just one leaky transformer down a storm drain to New Mexico’s lakes and streams.
“Everything ends up in the water,” Schiffmiller said. “Everything just goes downstream.”
Health Advisory
For fish contaminated with mercury, the advisory figures below show the maximum number of fish servings that children and pregnant or nursing women should eat per month, according to the state’s 2009 report. A single serving of fish weighs 8 ounces before cooking.
For fish contaminated with PCBs, the serving limit listed below applies to all people.
The servings are cumulative — that is, if you eat one serving of a 22-inch Channel catfish from Abiquiú Lake, you should not eat any other contaminated fish for a month. Species or sizes not listed have not been analyzed.
• ABIQUIU LAKE
Contaminants: mercury, PCBs
Brown trout, 10 to 18 inches: 4 servings
Brown trout, 18 to 22 inches: 2
Carp, 14-22 inches: 1 (contains PCBs)
Channel catfish, 10 to 14 inches: 3 (contains PCBs)
Channel catfish, 14 to 22 inches: 2 (contains PCBs)
Channel catfish, 22 to 26 inches: 1 (contains PCBs)
Rainbow trout, 10 to 14 inches: 8 (contains PCBs)
Rainbow trout, 18 to 22 inches: 3 (contains PCBs)
Smallmouth bass, 10 to 14 inches: 2
Smallmouth bass, 14 to 18 inches: 1
Walleye, 14 to 22 inches: 1
Crappie, less than 10 inches: 2
• EAGLE NEST LAKE
Contaminant: mercury
Rainbow trout, 18 to 22 inches: 4
White sucker, 10 to 14 inches: 4
• EL VADO LAKE
Contaminant: mercury
Brown trout, 10 to 18 inches: 8
Kokanee salmon, 14 to 18 inches: 8
White sucker, 10 to 14 inches: 4
• HERON LAKE
Contaminant: mercury
Kokanee salmon, 10 to 14 inches: 8
Kokanee salmon, 14 to 18 inches: 4
White sucker, 10 to 18 inches: 4
• RIO GRANDE (CHAMA RIVER TO EMBUDO CREEK)
Contaminant: PCBs
Carp, 18 to 22 inches: 1
Channel catfish, 14 to 22 inches: 1
White sucker, 14 to 18 inches: 1
Anglers can remove PCB and DDT contamination during cleaning and preparation. First, remove the skin, fat and internal organs. PCBs and DDT are stored in fat, so grilling, baking or broiling reduces contamination if you allow the fat to drip away.
Frying is not recommended, because it seals in contaminants.
Unfortunately, mercury is not stored in a fish’s fat and no cleaning or cooking methods can reduce mercury contamination.