Lead Free Angling - Fishing with a conscience

We are faced with many social and environmental choices in our day to day lives. Do we throw that scrap of rubbish in the garbage bin only to be hauled off to the landfill, or do we place it into a recycling bin to be used again? Should we use chemical or organic fertilizers on our lawn, or should we even have a lawn in the first place? Do we avoid using red dye in our hummingbird feeders? Should we worry about lead in our fishing gear? After-all, I’m just one guy occasionally losing a handful of split shot to the rocks. What’s the harm in that?

So many of our actions may seem benign at first, but when you add up our small actions and then multiply them by the global population, our actions become amplified. If we consider the number of anglers fishing a popular destination river such as the Madison, Yellowstone or even the Roaring Fork Rivers, we might start to see our individual choices have a larger impact on the ecosystem as a whole, when we add everything up.

On a midsummer day in July, I counted 35 drift boats cruise by me on a stretch of the Madison River in an 8- hour period of time. In each boat, there were at least two anglers. Hypothetically, let's suppose each boat was fishing the traditional western nymph and bobber technique popular with rowing guides. I cannot ascertain with what technique they were fishing, but suppose for the sake of this argument that all of the anglers were fishing with split shot attached to their leaders. It is not uncommon for anglers to lose a lot of gear, especially new anglers.

Let’s assume that each boat that drifted by was using nymphs that day and that each angler in each boat all had lost 6 split shot each. A single BB sized split shot weights .02oz. There were 35 boats x .24oz lost in each boat = 8.4oz.

That is over half of a pound of lead in one day alone!

If there are 100 guide days per season and 35 guided trips per day, on average, that equals 840 ounces of lead, or 52.5lbs, in one single river in one single year. FIFTY-TWO POUNDS OF LEAD.

It is highly unlikely that 52lbs of lead was actually lost to the river bottom that year, however, because not every boat was fishing with lead attached to the split shot or lead based weighted fly patterns. Even if only 20% of the anglers used and had lost lead rigs, it's still a lot of weight donated to the benthic zone in that year alone - possibly ten and a half pounds of lead.

I have not even mentioned the use of lead anchors. I watched one guide lose 2 anchors in one day on the Yakima River many years ago. Heck! That’s probably 20lbs of plumbum on the bottom.

As we have seen in our natural world, lead lasts a long time in the environment and can possibly migrate throughout an ecosystem. A case in point might be the California Condors, who have been suffering lead poisoning near the Grand Canyon due to lead shot used in hunting.

According to the Arizona Game and Fish Department[1]:

Lead toxicity has been identified as the leading cause of death in condors in Arizona’s California condor reintroduction program, and high mortality rates are the primary obstacle to recovery of this species. Multiple condors have died of lead poisoning since 2000. Condors are trapped annually to have their blood tested for lead. Biologists began testing for lead exposure in 1999. Each year, 45 to 95 percent of the condor population tests positive for lead exposure. Chelation treatment is often required to reverse dangerously high blood lead levels.  Surgery has also been necessary in the worst cases. Without these treatments, more condors likely would have died.

A number of scientific studies collectively provide strong evidence to support the hypothesis that spent lead ammunition is the primary source of lead exposure in condors. The information gained from these studies can be collectively presented as a set of scientific findings or observations, linked together to create a logic chain. Individually, each link in the following logic chain has been demonstrated by a scientific study, and collectively the links form a logic chain that provides strong evidence that lead ammunition is the most likely source of elevated blood lead levels in free-ranging condors.
—   http://www.azgfd.gov/w_c/california_condor_lead.shtml

 

I am not entirely certain if, or how, lead migrates through the food web of trout streams. A possible hypothesis can be made concerning lead in our aquatic ecosystems by reviewing some scientific literature by Dr A Cristini [2].

More complex aquatic plants, such as the submerged aquatic vegetation that have roots and a multi-celled structure, appear to take up more lead than plants without roots; this may be related to their absorption of lead from sediments. Uptake of lead in aquatic systems varies with many different factors including the pH of the water, the presence of other minerals in the water, and the availability of organic compounds or other chemicals that may bind up the lead, making it less available for uptake on the one hand, or on the other, actually facilitating its uptake by the organism. In some aquatic plants, rooted in sediments, lead taken up by the roots can be translocated or moved to the shoot, although lead can also be directly absorbed from the water especially if the lead concentration is high there. Lead measured in aquatic plants may also include that adsorbed at the surface or taken up by bacteria that reside on the surface of the plant. In one study, 46% of the lead measured from the plants was actually in the epiphytic (surface-resident) bacteria. Certain bacteria can increase the toxicity of lead to aquatic plants by synthesizing methyl- or other alkyl-lead compounds. These are organic compounds consisting of one or more carbon atoms and associated hydrogen atoms; the organic compounds are more soluble in the fatty membranes of plant and animal cells and more readily taken up. Although these methyl-lead complexes are not nearly as important in food chain contamination as comparable organic mercury compounds, they can be as much as twenty times more toxic than an equivalent weight of inorganic lead.

 

It has been observed that some forms of lead do not migrate up the aquatic food chain, however one can make a simple observation that lead in plant leaves will get eaten by bacteria that then get eaten by benthic macro invertebrates which belong to the shredder/scraper functional feeding group. Fish will then consume the macro-invertebrates and consume quantities of lead.

Dr. Cristini continues:

Even at lead concentrations at or below the 50 parts per billion previously considered safe in drinking water for human consumption, chronic lead exposure to fish may bring about increased mortality rates, reduced hatching success and indications of neurotoxicity as indicated by higher incidences of black tails (darkening of the caudal area) and spinal curvatures. In a Colorado stream that received contaminants after a dam holding back tailings from a mining site broke, rainbow trout exhibited neurological damage, including spinal curvatures and blackening of the tail. The stream contained up to 50 ppb of lead per liter of water. Because of the sensitivity of these fish, a Maximum Acceptable Toxicant Concentration (MACT) of 7.2 mg/l (ppb) has been suggested for rainbow trout. Brook trout also showed scoliosis (bilateral spinal curvatures), an abnormality of the spine, and reduced growth after long term exposure to lead. These effects lasted over several generations.
— http://www.rst2.edu/ties/LEAD/university/resources/experts/leadinanimals/animal1.htm

 

Dr. Cristini's paper continues to discuss the effects on waterfowl, humans, amphibians and crustaceans. As sportsmen and women, we may not even consider other impacts we are having which include the impacts on birds, waterfowl and amphibians.

More and more, we are learning that we are having a greater impact on our natural world. Alone, each individual may not pose a substantial risk but en masse, we pose far greater risks to our environment than we realize. Perhaps we start to look for alternatives to using lead in our fishing gear. Fly companies are starting to sell lead free flies, or even better, tungsten beaded flies, which sink fast. There are tungsten weights and sinkers and tungsten putty that can be used as well as tin split shot offering a viable alternative to lead.

[1]           http://www.azgfd.gov/w_c/california_condor_lead.shtml

[2]           http://www.rst2.edu/ties/LEAD/university/resources/experts/leadinanimals/animal1.htm