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Hook Fisherman, Scientists Study What Cod Eat

by Rebecca Love
This article was published in Working Waterfront, The Island Institute, January, 2003

Ted Ligenza, a Chatham-based fisherman of 30 years and a collaborative research participant for a little over one year, is trying to figure out what cod eat and when they eat it in an area east of Cape Cod, MA. Ligenza has teamed up with fisheries biologist Frank Almeida from the Northeast Fisheries Science Center for the study. The Northeast Consortium funded project began examining cod stomach contents in the fall of 2001 and will continue for another year.

Ligenza considers himself a biologist and a fisherman. "I find this work exciting, and I'm lucky to be able to do it." "When you're a fisherman, you know a lot about what they eat, where they are, where they spawn, but when you look at it through a scientist's perspective, its different."

When asked how he became so curious about cod's diet, Ligenza replies "every fisherman is interested in what fish eat. You'd have to be pretty dumb not to pay attention to this - especially if you're a hook fisherman."

At first, finding a scientist that wanted to dissect cod stomachs and examine the undigested contents was a challenge, but eventually Ligenza found the perfect person. After calling several scientists, Ligenza had almost had it. When he finally called Almeida, he told him he was the last person he was going to call. "He said he felt bad for me, but then he sat down and thought about it and said 'that's a really neat idea!'"

For the most part, this project has verified what the National Marine Fisheries Service's (NMFS) broad-scale survey has shown; however, this study is extremely valuable as it collects samples three times a month compared to twice a year for the NMFS surveys. Data from this project are "filling a temporal gap," says Almeida. "It is filling the gap between laboratory work and the stuff we do in our (broad-scale) survey." Almeida admits that it would be too difficult to expand this tri-monthly sampling technique along the entire coast of Maine; however, he says he'd also like to see this being done "off the coast of Maine where water temperatures are different."

Ligenza's sampling partner throughout the project has been Brian Smith, a research technician from NEFSC. Smith says that cod are opportunistic. "Schools of herring are basically coming to them (the cod) in December. A cod probably figures this thing just bumped into me; I guess I'll eat it."

One of the most unexpected things that Ligenza has noticed is how little fish eat sometimes. "Why do I get a fish with nothing in it when there is herring all around? What's wrong with them?"

Recently liver and gonad analyses have been added to the study. This information will help them compare stomach content analysis to spawning activity and overall health. Ligenza figures that gonad and liver weights may help shed some light on why cod sometimes choose not to eat. "People think of fish as eating machines, but they aren't. Maybe fish are like anaconda; they just don't need to eat all the time."

According to Ligenza, the best part of this project has been "the people." "I started fishing 30 years ago, so most of the people I know are fishermen. I really like getting to meet different people," Ligenza says with a broad smile.