Q. What is lead toxicosis? What are the symptoms?

A. Toxicosis is a diseased condition caused by poisoning. Lead toxicosis in birds occurs when liver lead concentration reaches 5 parts per million (ppm)(1) and when blood lead levels are greater than 0.2 ppm. Death occurs at blood lead levels greater than 1.2 ppm.(2) A single 1/16-ounce jig may cause the death of a loon within a few weeks.(3)

 

Acute lead poisoning can occur if a bird ingests several lead shot pellets or sinkers at once. The bird will probably appear to be in average health, but will suffer massive tissue destruction and internal organ damage, usually dying within days.

 

Waterfowl, predominantly ducks, geese, swans, and loons, are the wildlife most commonly poisoned by lead ingestion. However, upland game birds, such as pheasant, wild turkey, quail, and mourning dove, are also affected. Small mammals, like raccoons, and birds of prey, like raptors, also experience lead poisoning, primarily through ingestion of contaminated prey. Even songbirds have died from lead poisoning.

 

In heavily contaminated areas, poisoning may be seen throughout the year, while in other areas, it is primarily seen during the migration periods in early spring and late fall.

Q. How does lead poisoning from fishing tackle occur? What happens?

A. Poisoning can result from lead tackle in a number of ways. Many water birds ingest small pebbles (“grit”) to aid digestion. Loons, for example, often have as many as 20 to 30 pebbles in their gizzard. Small lead sinkers or jigs laying in the sand can be mistaken for pebbles and ingested. Other water birds may also mistake sinkers for dietary items like seeds or snails. Dabbling ducks, such as mallards and pintails, skim the bottom in shallow areas searching for and feeding on roots, leaves, and seeds. Diving ducks, swans, and geese dive to the bottom and probe the substrate for food. Shorebirds, such as rails and terns, probe the soft sediments along the banks and shallows.

 

In the bird’s gizzard, the lead tackle erodes and is dissolved. These lead salts are highly toxic and are absorbed into the circulatory system. There, the lead mimics the movement of calcium and is stored in bones and excreted into the feces via bile.

 

Signs of lead poisoning include lowered food intake, anemia, weight loss, drooping wings, impaired flying ability, loss of balance, gasping, tremors, and green watery diarrhea. As the poisoning worsens, the bird may hide among aquatic vegetation and miss migration. Death may occur within two weeks.

 

It is entirely possible that deaths from indirect effects of lead poisoning may outnumber the deaths directly related to lead toxicity. “Non-lethal” effects, such as anemia and weakened muscles, increase susceptibility to disease, infection, and predation. Additionally, birds can have difficulties breeding, nesting, and caring for their young. Immune suppression may also result.

 

Consumption of fish attached to lead tackle or fish that have ingested lead tackle can also lead to lead poisoning. Secondary lead poisoning has been documented in bald eagles, common loons, common mergansers, and red-breasted mergansers.

Q. Are any species besides loons affected by lead poisoning from fishing tackle?

A. Yes. Loons are the most studied because their mortalities are the most obvious but many species are affected.

 

At least 30 bird species are known to have ingested lead fishing tackle in North America:

American Black Duck American White Pelican Bald Eagle Brown Pelican Canada Goose Clapper Rail Common Loon Common Merganser Double-crested Cormorant Great Blue Heron Great Egret Greater Scaup Herring Gull King Rail

Laughing Gull Mallard Mississippi Sandhill Crane Mute Swan Redbreasted Merganser Redhead Duck Ring-necked Duck Royal Tern Sandhill Crane Snowy Egret Trumpeter Swan Whistling Swan White Ibis White-winged Scoter Wood Duck

Additionally, painted turtles and snapping turtles are known to have ingested lead tackle.

 

It is likely that osprey, which feed exclusively on fish, are regularly exposed to lead as well.

Q. What fishing equipment contains lead?

A. Suffice it to say, most tackle boxes are filled with lead. Jigs and sinkers are made primarily of lead. Spinnerbait bodies and downrigger cannonballs also contain lead, as do spoons and most crankbaits. A walk through any sporting goods section is enlightening – just look for the sticker: “WARNING: This product contains lead, a product known to the State of California to cause cancer and birth defects and other reproductive harm.” Literally, tens of thousands of items in any major sporting goods store’s fishing section contain that label.

 

Fortunately, the only fishing equipment that poses a major problem to loons and other birds, however, are the jig heads and the sinkers small enough to be swallowed. Therefore, this poisoning problem is a pretty easy fix.

Q. Are there alternatives to lead fishing tackle? Do they work?

A. Yes and yes. There are a number of large tackle manufacturers that make non-lead sinkers and jig heads and some smaller tackle companies which exist only to provide environmentally-friendly alternatives to lead fishing tackle. In total, approximately 20 manufacturers currently offer non-toxic alternatives to lead sinkers and jigs.

 

Non-lead alternatives are usually slightly more expensive than lead tackle. However, steel weights are generally less expensive than those made of lead. The most common non-lead alternative is tin, but increasingly tackle is being made out of bismuth, ceramic, recycled glass, stainless steel, granite, antimony, tungsten, tungsten-nickel alloy, or thermoplastic composites.

 

Today’s non-lead alternatives perform quite well. The following quote from sporting goods company Cabela’s Spring 2002 Master Catalog sums it up nicely:

It’s not a big secret that the use of lead for sinkers, shot, and other recreational purposes is quickly becoming regulated. As a matter of fact, in many areas where waterfowl and other bird species are present, the use of lead has been completely eliminated.

As with non-toxic shot, steel has been found to be an economical alternative to lead and, in the case of sinkers for fishing, it actually has proved to outperform lead due to its hardness and resistance to deformation. They retain their shape, have clean chamfered holes that will not cut line, and outperform lead in almost all fishing situations. Promote the environment while improving your catch with these environmentally friendly weights.

Tungsten and bismuth may also perform better than lead. Lead’s great advantage over most alternatives is its density, which allows anglers to use smaller sinkers. Bismuth, however, is only 14% less dense than lead and tungsten is actually 70% heavier than lead.(4) Tungsten-nickel alloy weights are approximately 25% smaller than comparable lead weights. The alloy is also much harder then lead, making the weights less susceptible to deformation and grooves that can slice through the fishing line. Plus, they create twice the sound (and resultant vibration) of other weights – which can trigger greater fish reaction.

As more large tackle companies manufacture non-lead alternatives and focus more of their efforts into those alternatives, technology will improve and prices will lower, similar to when lead shot was banned for waterfowl hunting. Early steel shot prices were quite high, but increased consumer demand resulted in lower prices, increased product diversity, and technological improvements. Until companies are forced to provide non-lead alternatives, there’s not an incentive to develop such alternatives.

A 1994 U.S. Environmental Protection Agency report indicated that the average angler spent between $1.50 and $3.50 on sinkers annually. Nontoxic alternatives might increase that cost by $4.00 per year. In the end, however, money spent on sinkers will still amount to a small fraction (about 3%) of the average angler’s overall expenditures on the sport.(5) It certainly seems unlikely that a couple of extra dollars is going to persuade some to abandon the sport or refuse to fish in their state’s waters. In fact, some may even find the increased cost of tackle offset by their knowledge of the good they are doing.

Click here for a link to an article that include a list of non-lead manufacturers, short descriptions of their products, and links to their sites.

Figure 1: Comparison of Lead and Alternatives