Researchers develop new bait for eel, whelk

Synthetic product will reduce pressure on critical horseshoe crab populations.
DNREC Secretary Collin O'Mara congratulates University of Delaware researcher Dr. Nancy Targett on the unveiling of a new composite horseshoe crab bait. BY MOLLY MACMILLAN
June 27, 2013

For nearly 20 years, scientists have been working to figure out why horseshoe crabs are the best bait for eel and whelk and to produce a substitute.

Dr. Nancy Targett, dean of the University of Delaware's College of Earth, Ocean and Environment and director of Delaware Sea Grant says that work is now bearing fruit. Scientists recently unveiled a new, synthetic bait that is highly attractive to eel and whelk, yet uses only a fraction of the horseshoe crabs previously needed in the industry.

"We developed an artificial bait that's affordable and more easily stored," Target said. It's a win-win."

The artificial, composite bait her research team developed uses a small amount of ground horseshoe crab, compounds in brown seaweed, food-grade chemicals such as baking soda and citric acid, and tissue from an invasive species, the Asian shorecrab.

The addition of the Asian shorecrab allows researchers to reduce the amount of horseshoe crab tissue needed from one-half a female crab to one-sixteenth.

In addition, it's no longer only female crabs that are used as bait.

"We found that it didn't matter whether we used female or male horseshoe crab tissue in the artificial bait," Targett said.

The project, a partnership with DuPont Chemicals, Delaware Sea Grant, the Delaware Department of Natural Resources and Ecological Control and LaMonica Fine Foods was initially prompted by studies that showed eel and whelk were attracted only to traps baited with female horseshoe crabs.

With the help of scientists from DuPont Chemicals, Targett's team initially sought to identify chemical compounds in female horseshoe crabs that attract eel, substances that could be synthetically duplicated to reduce the need to harvest horseshoe crabs.

Horseshoe crabs are a valuable natural resource: They are an important food source for endangered red knot shorebirds, and their blood is also used in the pharmaceutical industry to ensure products are free of bacterial contamination.

Recognizing the ecological importance of horsehoe crabs, DNREC Secretary Collin O'Mara noted the financial impact of this project, growing a new business to manufacture synthetic bait while bolstering the eel and whelk fishing industries.

"I'm so excited about this project," O'Mara said. "I think it is a model for what we want to do."

Ecologically speaking, reducing the number of invasive Asian shorecrabs will also benefit the estuaries, Sea Grant aquaculture and fisheries expert John Ewert said.

Asian shorecrabs compete with native species and crowd them out of their own native habitat, Ewert said, so reducing the invasive population will help native species rebound.

"They compete with the native crabs. They can take over the habitat and force the native species out," he said. "The best way to get rid of something is to make it valuable."

For more information on pre-made, artificial bait call Michael LaVecchia at LaMonica Fine Foods at 856-825-8111, ext. 102.