DURHAM, N.H. For such a small shark species, there seems to be super-sized confusion about its population status. But for researchers at the University of New Hampshire, one thing is clear definite changes have occurred to spiny dogfish shark populations in the past two decades.
Commercial fishermen haul up nets loaded with so many of the three-foot-long sharks that the yellow-eyed creatures are often considered a nuisance. However, fishery management plans have set quotas to limit the harvest of dogfish to 3,000 pounds per trip in state waters due to concerns by scientists that the species could easily be overfished. The market for dogfish meat is located primarily in England and Germany, so dogfish caught in the Gulf of Maine are shipped overseas.
Confusion over their population status is compounded by the fact that there are relatively few recent studies to document dogfish ages, growth rates and maturity. In fact, it has been more than 20 years since the last life history study was conducted for dogfish in the Gulf.
"In order for management to be effective, we need updated and accurate biological information, we need to accurately age these fish and determine their age at maturity," says Paul Tsang, UNH professor of molecular, cellular and biomedical sciences. "To really understand what's going on with their populations, we need to understand their basic life history."
Tsang is collaborating with University of New England professors David Koester and James Sulikowski to establish basic biological information about dogfish populations in the Gulf of Maine. Spiny dogfish sharks are part of the Elasmobranch family, which includes sharks, skates and rays. With funding from N.H. Sea Grant, UNH Ph.D. candidate Walter Bubley is working with Tsang to determine the average and maximum age, growth rate and age at maturity for this species.
Bubley worked closely with New Hampshire commercial fishermen to collec
|Contact: Rebecca Zeiber|
University of New Hampshire