Black sea bass feature prominently on many menus, but wild populations of the fish are in decline and their availability is limited. Because of the high demand, they're a good candidate for aquaculture on the east coast. Except, that is, for one problem: they have a tendency to change sex unpredictably in captivity.
"In the wild, black sea bass are born as females and turn into males at around two to five years old," Berlinsky explains. "When you bring them into captivity, they change into males more quickly." Some captive-born fish emerge as males even before reaching adulthood, devoting energy toward reproductive development and away from growth. Such problems make breeding and growing the fish in captivity a tricky proposition.
"Black sea bass is a wonderful fish to culture and to eat," says George Nardi, vice president and director of GreatBay Aquaculture, a commercial fish farm in Newington, NH. But the sex change problem must be tackled if fish farmers are to bring a high-quality fish to market. "We invest in our brood stocks, the parents of the young fish, much as a thoroughbred horse farm invests in mares and stallions," he says. "It doesn't do us much good if we always have to go out and get new females."
With funding from NH Sea Grant, Berlinsky has teamed with Nardi and GreatBay Aquaculture to study what triggers sex reversal in black sea bass ?and how to prevent it. Berlinsky and his colleagues have discovered that fish are more likely to become males if raised at constant temperatures. But temperature is hardly the only factor involved. Sex ratios and density also
Source:University of New Hampshire