Survival Chances Brighten for Sunshine BassBy Ben Hardin
February 10, 2000
Aquaculturists now can produce sunshine bass, the ever-popular hybrid fish, more efficiently by preventing them from being gobbled up by one of their own foods--zooplankton. Thats good news for sunshine bass producers--a small but rapidly developing industry.
The trick: stock ponds with the fish when two other morsels, microscopic rotifers and minute crustaceans, become plentiful but before zooplankton grow large enough to devour the tiny, newly hatched fish.
As newly hatched fry, sunshine bass are 2 to 5 millimeters long and vulnerable. Agricultural Research Service scientists have developed charts and graphs that identify the precisely timed window of opportunity when pond stocking allows fish to eat and grow fast enough to avoid becoming prey for larger zooplankton.
Research showed pond temperature strongly affected the rotifer supply buildup. And rainfall drove the growth of the crustacean copepod nauplii. Other influences included day length, dissolved oxygen levels and the air temperature outlook.
Before sunshine bass--a cross between male striped bass and female white bass--began making a splash, east coast fishermen in the early 1980's annually peddled up to 14.7 million pounds of striped bass to fish markets. Overfishing and pollution essentially destroyed the industry. Since 1984, the annual production of sunshine bass has increased from 10,000 pounds to 15 million pounds.
Research on sunshine bass may improve the culture of additional tasty species of fish like yellow perch and walleye. If technology affords consumers year-round choices from among several cultured species, steady buying habits may develop. Then farmers may not have resources lying idle much of the year. The scientists are researching ways to manage fish so theyll spawn all year round, and theyre developing know-how for providing a year-round supply of live food.
ARS is the U.S. Department of Agricultures chief scientific research agency.
Scientific contact: Gerald M. Ludwig, ARS Harry K. Dupree Stuttgart National Aquaculture Research Center, Stuttgart, Ark., phone (870) 673-4483, fax (870) 673-7710, firstname.lastname@example.org.