URBANA, Ill. – Soft plastic fishing lures don’t degrade, don’t decompose, even after two years of being discarded, and are being found both in nature and inside fish. University of Illinois researcher Cory Suski, in collaboration with Steven Cooke from Carleton University in Canada, studied the unanticipated impact of the soft lures on lake trout, smallmouth bass, and the environment. The soft plastic lures look like worms, leeches, or crayfish and are particularly enticing to fish, making them very popular with anglers. The material they’re made from feels like gelatin, like an inedible version of gummy worms.
For the field portion of the study, snorkelers searched for broken or discarded lures along the shoreline in Charleston Lake in eastern Ontario. They found as many as 80 lures approximately every 50 miles.
“We don’t think that people are discarding them intentionally,” Suski said. “They just drop off the hook or half of it rips off the hook and sinks to the bottom where they can’t be easily retrieved.”
In the lab portion of the study, eight different types of soft plastic lures were immersed in water at two temperatures for a two-year period to evaluate the change in size and the rate of decomposition.
The fact that there was little evidence of decomposition over the two-year span makes the lures’ “shelf life” in the environment troubling.
“If a lure is swallowed and swells, it fills the fish’s stomach, and the fish likely will have problems with digestion,” Suski said. “Interestingly, swelling varies from lure to lure depending upon the brand—some up to 200 percent of their original size. We aren’t saying that one lure is better than the other, but that it is likely possible to create lures that don’t swell as much or ideally that degrade quickly.”
Suski was relieved that the rate of lure ingestion by fish was lower than the numbers they had anticipated from earlier studies conducted with fish in laboratory tanks and was also lower than he had anticipated based on the number of lures discovered in the lake.
“Rather than saying let’s ban these lures, we can likely work with anglers and the industry to improve things,” Suski said. “What we’ve found in many projects is that anglers want to do the right thing. They care about the environment, but sometimes they just don’t know how their actions are affecting the environment – after all, before this study, no one had quantified how many of these lures had been lost. So if we tell them that a lot of lures are being dropped and they stay around for two years, they’ll likely change their behavior and be more careful.”
Some states are considering legislation that would ban the use of soft plastic lures because of the potential threat to fish and wildlife, but Suski believes that changes can occur without regulations.
For example, anglers might use alternative rigging methods such as an o-ring on stick baits so that the lure will stay on the hook. More information about how to properly dispose of the soft plastic lures may also be beneficial. Suski said that there are already some grassroots initiatives from the recreational fishing community that encourage anglers to deposit used lures in the trash. Another effort is a program called Re-Bait that promotes proper disposal of lures. Suski noted that the effect of the ingestion of soft lures on birds, turtles, and snakes is unknown.
“Exploring the Potential Effects of Lost or Discarded Soft Plastic Fishing Lures on Fish and the Environment” was published in a 2014 issue of Water, Air, and Soil Pollution. In addition to Cory Suski, Travis Raison, Alex Nagrodski, and Steven Cooke contributed to the paper. The research was partially funded by Carleton University and the Charleston Lake Cottagers.