Researcher Seeks Better Production Systems
for Sunshine Bass By Jim Core
An Agricultural Research
Service scientist has taken several key steps toward the development of a
year-round supply of sunshine bass fingerlings.
The research by Gerald Ludwig, a biologist with the ARS
Harry K. Dupree Stuttgart National
Aquaculture Research Center in Arkansas, involves small zooplankton called
rotifers. Ludwig has found that sunshine bass must be stocked just before
rotifers become the dominant zooplankton in production ponds where small fish,
called fry, are raised. Sunshine bass, being smaller than wild striped bass,
can't feed on larger crustaceans and need the smaller rotifers as a food
Ludwig developed equations to predict when rotifers will make
their appearance in outdoor fry production ponds. He and ARS agricultural
engineer Tim Pfeiffer also devised an automated indoor feeding system for
rotifers, ensuring that fry will have live rotifers throughout the year.
Demand for farm-raised sunshine bass--also known as hybrid
striped bass--began in the mid- 1980s after supplies of wild-caught striped
bass decreased. As part of his research, Ludwig studies the ecology of ponds
where sunshine bass are raised. He also develops new methods of rearing fry
indoors to increase production of fingerlings.
Typically, sunshine bass fry are raised in outdoor rearing ponds
until they're 35-40 days old. Then they're called fingerlings and are fed
commercial pellets. Fingerlings are generally available in the southeastern
United States from May to June. If more fingerlings were available, especially
year-round, they could increase production of market-sized fish and stabilize
seasonal price fluctuations.
According to Ludwig, many factors are involved in timing fry
stocking just right, including water temperature and the amount of forecasted
Indoor production is required in temperate climates if producers
are going to have a year-round supply of fingerlings. Ludwig produced hybrid
striped bass fry in indoor tanks for the first time by feeding them freshwater
rotifers, which he also cultured indoors.
about this research in the June issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.