New Research Looks at Changes in Relation Between Cunner and Lobster

By Carli Stewart, National Fisherman, reprinted with permission

Researchers at the University of Maine (UMaine) are taking a closer look at whether cunner fish may be preying on lobsters in a new way, particularly targeting egg-bearing females. The work is being led by fisheries scientist Michelle Staudinger, backed by a National Geographic Society grant aimed at studying keystone species and emerging ecosystems shifts.

Cunner are generally less than a foot in length. Their mouths are lined with several rows of cone-shaped teeth. Photo courtesy pf the Staudinger Lab.

Cunner aren’t new to the Gulf of Maine. The small, colorful fish have always fed on young lobsters in their early benthic stages, along with clams and snails. But recently fishermen and the Maine Department of Marine Resources have reported cunner showing up in traps, and in some cases with lobster eggs in their mouths.

“We don’t know if this behavior has been happening and gone unnoticed or if there is an environmental factor causing it to happen now,” Staudinger said. “We would like to gather evidence to determine how widespread it is, and the best way to do that is to work with the fishermen who are on the water every day and see cunner in their traps.”

To get answers, researchers are turning to environmental DNA to analyze cunner stomach contents, which is needed because the species’ crushing teeth make traditional diet analysis difficult. The goal is to determine whether this is a localized issue or something broader.

Recent research on lobster embryos found that higher water temperatures can speed up development but result in smaller larvae at hatch, which could be more easily eaten by predators such as cunner.

Shifts in prey availability also may be playing a role. Staudinger noted historical research showing cunner favor shellfish like mussels, a species that has declined in some areas, raising the possibility that the fish are moving to new food sources.

The UMaine team says the work could identify “hot spots” where cunner and egg-

bearing lobsters overlap, offering insights into where and when interactions are most likely. It could also lead to practical solutions, like trap modification to deter fish. The findings may also show the issue is limited in scope, something that could ease another concern for lobstermen.

Seen a cunner?

If you find a cunner with lobster eggs in its mouth, the Staudinger Lab is asking you to take a photo and text it to 508-348-9039 or email it to cunner.maine@gmail.com, with the date the fish was caught and its location. If possible, measure the cunner or take a picture of the fish with a measuring tool. Visit the Staudinger Lab at https://umaine.edu/staudingerlab/novel-predatory-threats-to-lobster to learn more.