Get the Lead Out!

I'm not talking about the lead in one's shoes or pants, but rather the lead that ends up lying on the bottom of rivers and streams as the result of fishermen having to break off their fishing lines. In case you haven't checked, lead is toxic to all wildlife. Birds, such as the red-throated loon (right), especially are at risk of lead poisoning because they often hold lead objects in their gizzard, rather than passing them through their digestive systems.

According to the U.S. Environmental Protection Agency, there are 75 species of birds at risk from lead tackle. One specie hit hardest is the common loon in the Northeast, where lead poisoning has been the leading cause of death among hundreds of adult loons over the last 25 years. In New York alone, lead poisoning has accounted for about 30 percent of documented loon mortality.

The lead fishing weights (left) ingested by loons can be categorized as sinkers or weighted lures, which are frequently lost when snagged on rocks, fallen trees, or other submerged hazards. They also sometimes are simply dropped or spilled while handling and not recovered.

Why loons consume these objects has not been studied, but the reasons are likely multiple. It has been proposed that loons mistake lost sinkers for the small stones they regularly ingest to help grind fish bones and crustacean shells in their muscular stomach. However, since hooks, brass swivels, and pieces of fishing line often accompany sinker remains in loon stomachs, it seems more plausible that sinkers are incidentally ingested when loons swallow minnows or crayfish attached to rigs that have been lost.

Finally, and very importantly, lead-weighted lures resemble prey items and are probably mistaken for such by loons. The fact that the lead objects found in loons in New York most frequently have been of lure origin, rather than sinker origin, would seem to support the ingestion of sinkers incidental to the bait-consumption hypothesis.

In recognition of the threat to loons and other birds, including the bald eagle, ducks, geese, swans, herons, gulls, and terns, the sale or use of lead fishing weights has been variably restricted in recent years in a number of locations in the United States and Canada. New Hampshire, for example, prohibits the use and sale of lead jigs and sinkers with a total weight of one ounce or less. Maine and New York have banned the sale of lead sinkers weighing less than half an ounce. The use of lead sinkers and jigs weighing less than 50 grams is prohibited in Canadian national parks and national wildlife areas. And finally, lead sinkers are currently prohibited in three national wildlife refuges in the western United States.

Alternatives to lead now available in sinkers and jigs include steel, bismuth, tin, tungsten, alloys of these metals, and metal/plastic or metal/ceramic combinations. There also are fishing weights made from zinc, but you should avoid these because zinc is sufficiently toxic by ingestion that it could, like lead, threaten loons and other aquatic birds.

Not long ago, hundreds of thousands of waterfowl died every year from the ingestion of lead shotgun pellets deposited in wetlands across North America. Since the nationwide ban on lead-shot use for waterfowl in 1991, though, lead poisoning in waterfowl has been greatly reduced. With help from anglers, another step can be taken to get lead out of the environment, too. Loons, other wildlife, and humans will be the better for it.