As open-water fishing season gets under way, the Maine Department of Inland Fisheries and Wildlife is strongly encouraging anglers to protect Maine’s fish by changing from soft plastic lures to biodegradable ones.
DIF&W fisheries biologists are reporting increasing numbers of angled trout and salmon with indigestible soft plastic lures in their stomachs. A discarded soft plastic lure consumed innocently by a brook trout from the bottom of a freshwater shoal likely remains in that fish’s stomach for the rest of its life and may cause health issues such as ulcers and weight loss.
Soft plastic lures are most commonly used by bass anglers, often in waters shared with trout and salmon.
DIF&W is cooperating in studies on the effects of soft plastic lure ingestion by trout and salmon, including one recent experiment at Unity College, which was conducted by DIF&W pathologist Dr. Russ Danner, Unity College professor Jim Chacko and DIF&W fisheries biologist Francis Brautigam, and in another study currently under way at Southern Maine Community College.
The study conducted at Unity College found that 65 percent of brook trout voluntarily consumed soft plastic lures if they simply were dropped into water.
“We found that fish retained the lures in their stomachs for 13 weeks without regurgitating them,” according to Dr. Danner. “They also began to act anorexic and lost weight within 90 days of eating a soft plastic lure.”
Without regard to the chemical toxicity of ingested soft plastics, the fact that these lures are occupying space in a trout’s stomach limits the amount of space available for natural food. There is a lot of veterinary medical evidence that foreign bodies in the digestive tract cause ulcers, weight loss and anorexia.
“We strongly encourage anglers to voluntarily purchase biodegradable and food-based lures rather than soft plastic ones,” Dr. Danner said. “Also, we are asking anglers not to discard plastic lures into any waters, and also to attempt to retrieve any soft plastic lures that have become unhooked.”
For millennia, trout and salmon have foraged the waters of Maine for nutritious natural forage such as small fish, insects and other invertebrates. In the last 20 years, food mimics made of soft plastic have begun to compete with these nutritious natural forage items. The effects of soft plastic lure pollution on freshwater ecosystems are not well understood yet, but it is unlikely that eating soft plastic lures will be found to be a good thing.
“The wide assortment of soft plastic fishing lures is staggering,” Dr. Danner said. “Soft plastic lures come in every color, a myriad of sizes, and resembling every swimming, crawling and flying creature a fish could imagine eating. Large fish searching the waters of Maine are bound to come upon brightly colored soft plastic lures lost or discarded by anglers and consume these imitators of natural food items.”
There are estimates that as much as 20 million pounds of soft plastic are being lost in freshwater lakes and streams annually in the U.S. The average life expectancy for these soft plastic lures is more than 200 years.
“We need all anglers to do their part to protect Maine’s valuable fisheries from this serious threat,” Dr. Danner said. “Natural lure alternatives are available at many retailers and online and should become the choice of people who love to fish Maine’s waters.”
To learn more about the experiment conducted at Unity College a report on the project was published in the Northern American Journal of Fisheries Management. It is available at afs.allenpress.com/perlserv/