RICHMOND — The next time you slice up your favorite saltwater fish, consider donating its carcass to science.
The Virginia Marine Resources Commission soon will begin collecting carcasses of several elusive species from recreational fishermen to study the health of fish populations. Cobia, spadefish, sheepshead, red and black drum, tilefish and grouper will be examined.
Since 1998, the commission has collected length, weight, sex and age information on more than a dozen species in the Chesapeake Bay. The majority of the samples come from the commercial fishing industry, but some of the species aren’t popular commercial catches, so the commission is turning to recreational fishermen to fill the gaps.
“Instead of going out and catching live ones ourselves, we can get much of the data that we need from the remnants of what’s already caught,” commission spokesman John Bull said.
To determine its age, scientists must remove a fish’s otolith, an ear bone that contains growth rings similar to rings in the trunks of trees. Hundreds of samples are needed each year for researchers to get an accurate reflection of the population.
“Why go and kill new fish to do the studies when we can learn the stuff from the dead fish?” Mr. Bull said. “That leaves more fish out there for other people to catch.”
He called the project a “normal, routine, health-of-the-species population assessment” and said scientists have no reason to think any of the targeted species are in serious danger.
Researchers are interested in how long the fish are living, how big they’re growing and the ratio of females to males, which can be used to project the viability of the species.
The project targets fish that are most difficult to catch. Species such as flounder and striped bass are prevalent in the Chesapeake Bay, but the targeted fish either don’t inhabit the Bay in large numbers or don’t bite as often, Mr. Bull said.
Last year, 26,000 cobia were recorded caught by recreational fishermen, and all but about 8,000 were released, Mr. Bull said. In contrast, recreational fishermen caught more than 67,000 striped bass during a four-week season last year in Maryland alone.
A project set up last year to collect sheepshead carcasses produced only 174 donations, said Hank Liao, a scientist at Old Dominion University’s Center for Quantitative Fisheries Ecology. The commission funds the center’s Growth and Age Lab where last year Mr. Liao and another full-time scientist examined about 6,000 fish.
Mr. Liao said 200 to 1,000 fish carcasses are needed to get a proper scientific sample, depending on the species. Some such as striped bass live longer, so more samples are needed to get an accurate reflection of the population. Others such as spotted sea trout have very short life spans and only about 250 are required for study.
Cobia remain one of the most elusive. Last year, scientists had only 30 samples to study, Mr. Liao said.
But organizers of the Marine Sportfish Collection Project are hoping anglers will come to them.
Recreational fishermen will be able to drop off carcasses head and tail intact in freezers at several bait shops spread out across the Chesapeake Bay area. They will receive a T-shirt in return.
Mr. Bull only hopes anglers will package the remains neatly.
“Hopefully they’re not all just dumping their fish skeletons in a freezer and walking away,” he said.
The project will continue indefinitely.
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