Gulf Coast Research Laboratory

Spotted Seatrout Research Hits Milestone at GCRL

February 6, 2006

OCEAN SPRINGS -- Researchers at the University of Southern Mississippi Gulf Coast Research Laboratory (GCRL) are expecting a bumper crop of babies this summer.

Scientists with Mississippi's first spotted seatrout stock enhancement program moved females and males – broodstock – from quarantine facilities Thursday into special tanks to begin the process of egg development. Rebuilding the native Mississippi broodstock lost to Hurricane Katrina is a first step in the program's comeback.

Also known as speckled trout, spotted seatrout rank as the most popular recreational coastal fish in the Gulf of Mexico and South Atlantic. The GCRL and the Mississippi Department of Marine Resources (DMR) launched the program in May 2004 to ensure that anglers will have a supply to catch. Christened the Seatrout Population Enhancement Cooperative (SPEC), the project is developing the “how-to” for rearing Mississippi spotted seatrout in captivity and will test the use of hatchery-produced fish for enhancing the natural population.

Before Katrina, GCRL scientists had developed a native Mississippi broodstock population that was near spawning at the time of its loss to the storm. The scientists had also successfully tested the laboratory’s rearing system, using spotted seatrout from eggs provided by an out-of-state program. Never intended for release, those fish perished from lack of oxygen when flooding shut down pumps during the storm.

Dr. Reginald Blaylock, principal investigator, said that even before the storm there was no ready supply for larvae from Mississippi seatrout.

"We are working on that challenge now," Blaylock said. "We are moving the broodstock into tanks with temperature and light controls. We expect that they will spawn in mid-summer."

Once spawning occurs, researchers will harvest the eggs – which could be as many as a million per tank -- and move them to the hatchery. When the eggs hatch, the larvae will go into the nursery. Equipment and temporary facilities are on the way to replace the hatchery and nursery destroyed in the storm. The facilities and research were part of the GCRL's estimated $50 million in losses, part of the overall $298 million in losses the university experienced from Katrina.

Dr. Jeff Lotz, chair of the Department of Coastal Sciences at GCRL, said an important part of the investigation is to determine what impact the released fish have on the resource. The team will develop effective tagging procedures and assess information from fish reared at the GCRL, released and then recaptured.

Blaylock said once the fish spawn this summer, researchers will tag the young in about 60 days after they hatch. Release of the tagged fish will be the first in a series of experimental releases – all with spotted seatrout reared at the GCRL and all offspring of native Mississippi stock.

"If the results show that the released fish have a positive effect on Mississippi seatrout populations, then the use of cultured seatrout becomes a tool for supporting the fishery," Blaylock said. "It is another tool that goes into the tool box to maintain fisheries so they are not depleted."

The Gulf Coast Research Laboratory is part of the university's School of Ocean and Earth Sciences within the College of Science and Technology.

For more information go to http://www.usm.edu/gcrl/research/seatrout_main.php