Fisheries researcher raises alarm about rubber worms

rubber wormsThis is the third in my five part series on the issues and problems surrounding the use of rubber worms for fishing. Part one presented the concerns of Henry Whittemore that “Rubber baits are killing both our wild and hatchery fish.” Today I will answer Henry’s questions and give you more information that a fisheries researcher shared with me.

Answering Henry

Henry posed these questions:  “Whom should I contact at IF&W?  Is there any chance that Maine’s fishing regulations can be adjusted to attempt to control this?  And, more importantly, is there any hope that manufacturers of such baits could make them from materials that could be digestible, biodegradable, even nutritive?  I believe corn starch, brewery waste and other such materials might be able to be adapted to such a purpose. Have you run into this before?”

I would start with Francis Brautigam, the new Director of DIF&W’s fisheries division. But I do not believe there is any chance that Maine will ban the use of rubber worms. In the last column on this issue, I told you about the last time this was attempted. I don’t know much about what manufacturers are doing – other than opposing these bans. And yes Henry, we have run into this before!

Info from fisheries researcher

A person who has been involved in fisheries research for quite a few years shared the following information with me about this issue and problem.

Unfortunately, Henry’s tale is just one example of a much bigger story that is insidiously playing out all over our inland and coastal waters.  Discarded soft plastic lures (SPLs) pose a direct threat to native species (and not just fish), constitute unsightly litter and are bad for the environment.

Fish frequently ingest SPLs — if they weren’t effective, then why would anyone use them?  They can also be directly ingested by loons and indirectly ingested by other piscivorous birds such as osprey and eagles.  Once the animal ingests one of these big hunks of plastic, it can become lodged in the intestinal tract and since they are not digestible or biodegradable, it is almost always a death sentence.

Worse yet, chemically enhanced (i.e. scented) SPLs are all the rage these days, making them even more appealing to fish & wildlife.  Anecdotally, any spin fisherman who has used the new chemical-attractant soft plastic baits in comparison to a standard un-scented artificial lure will be quick to tell you that the former is much more effective.  Not only does this increase the probability that these lures will be ingested after being discarded, these scented SPLs are arguably more similar to natural bait than other artificial lures are therefore may also increase the rate of hooking mortality in fish.

In 2014, MDIFW was mandated by legislative resolve to conduct a study to examine the use of rubber lures and nondegradable fishing hooks and lures.  Their findings were disturbing.  The study examined salmonids harvested from 22 southern ME waters from 2004 – 2012: Brook trout and lake trout had the highest occurrences of ingested SPLs.

Discarded SPLs also constitute unsightly litter at an alarming volume: An estimated 20 million pounds of SPLs are lost or discarded every year.  And despite manufacturers’ claims, studies have shown that these plastic baits do not decompose.  In fact, a study by Raison et al. demonstrated that most soft plastic baits in fact swell when submerged in water for an extended time: “In cold water, SPLs increased an average of 61 % in weight and 19 % in length, while warm water treatments experienced an increase of 205 % in weight and 39 % in length.”

Plasticizers, such as phthalates, are a major chemical constituents of plastics.  Phthalates are frequently used in soft plastics and are used to make these these lures flexible.  Like other petroleum-based plastic products, SPLs will leach chemicals into the environment.   Specifically, we know that phthalates have been documented to negatively affect aquatic life and may concentrate in some organisms.

Unfortunately, the 2014 IFW report cited above concludes: “Requiring the sale and use of only biodegradable SPLs is currently not a solution. There is currently no standard national or international definition for what constitutes “biodegradable plastic” and SPLs specifically. Based on the information presented in this report, the Department does not recommend any legislation at this time.”

So what are we doing about it?  Apparently not enough.  In fact, the voices of trout and salmon anglers are eerily quiet in this discussion.  Top Google search results on the topic of SPLs primarily list studies and outreach efforts associated with bass, not salmonids.  The bass fishing industry is doing a far better job of educating anglers about the consequences of using SPLs (and of course the bass industry is also doing a far better job of promoting C&R … ironic?)

Up Next

Tomorrow I’ll present the testimony of the American Sport Fishing Association against legislation to ban the use of rubber worms, and on Friday, I’ll give you the results of DIF&W’s study, order up by the legislature, including a lengthy list of recommendations.

George Smith

About George Smith

George stepped down at the end of 2010 after 18 years as the executive director of the Sportsman’s Alliance of Maine to write full time. He writes a weekly editorial page column in the Kennebec Journal and Waterville Morning Sentinel, a weekly travel column in those same newspapers (with his wife Linda), monthly columns in The Maine Sportsman magazine, two outdoor news blogs (one on his website,, and one on the website of the Bangor Daily News), and special columns for many publications and newsletters. Islandport Press published a book of George's favorite columns, "A Life Lived Outdoors" in 2014. In 2014, George also won a Maine Press Association award for writing the state's bet sports blog. In 2016, Down East Books published George's book, Maine Sporting Camps, and Islandport Press published George and his wife Linda's travel book, Take It From ME, about their favorite Maine inns and restaurants.