- Marine biologists at The University of Southern Mississippi are
tracking red snapper this fall to find out what happens to hatchery-raised
fish released on offshore reefs.
released radio-equipped fish this week in the Gulf of Mexico, about
20 miles southeast of Horn Island this week.
The radio tracking
experiment is part of a program to determine if using hatchery-raised
fish is an option to enhance depleted marine fish populations in
the gulf and what techniques will make it work best. Forty-five
fish from a total of about 1,500 released over a three-week period
have been tagged with the thimble-sized transmitters.
were all spawned, hatched and reared at the Gulf Coast Research
Laboratory here. The Southern Miss lab is headquarter for the U.S.
Gulf of Mexico Marine Stock Enhancement Program, in its sixth year
through the support of the National Marine Fisheries Service, an
agency of the National Oceanic and Atmospheric Administration.
enhancement has never been done before for offshore marine fish,"
said Dr. Reg Blaylock, one of the project's principal investigators.
"In addition to developing the technology to grow the fish
and release the fish, we are developing the techniques to assess
the effect of the release."
has chalked up a host of firsts for rearing, tagging and release
of the species that is in high demand and is designated by the federal
government as overfished in the gulf.
the stock enhancement research team has used radio tagging with
larger snapper, but never before with hatchery-raised fish so small
- four to six inches.
using routine technology to address a specific question about red
snapper stock enhancement: What happens to the fish after they are
released?" he said. "With stock enhancement programs,
you have to make sure that the fish live and that you are supplementing
the wild population instead of replacing it."
five acoustic receivers were tethered to the gulf bottom prior to
the first release in October and left to float in the water column
about 10 feet off the bottom. The battery-powered receivers will
record data for two to three months.
To tag the
fish with the radio equipment, researchers make a slit in the fish's
abdomen, insert the tag and stitch up the incision. The fish do
well and within a couple of days are ready for release. The snapper
are transported out to the reef in tanks. Then they are flushed
through a hose that delivers them to the reef about 70 feet beneath
the water's surface.
Gulf Fishing Banks, Inc., built the reef specifically for the laboratory's
snapper research and development work, Blaylock said.
fish passes within range, the receiver records a beep. You can then
go retrieve the information and download data. The information will
identify which individual is going where."
is the third and final in this year's tagging experiment. Each release
has placed on the reef approximately 500 snapper that were spawned,
hatched and raised at GCRL. Fifteen from each release carry the
radio acoustic tags. The research team tagged all 1,500 with a wire
tag that is coded with information plus a color-coded elastomer
tag - a polymer of different neon colors injected into fin and tail.
that stock enhancement for marine fishes is more complicated than
applying the well-developed technology used for enhancing populations
of freshwater species and species such as salmon that spend part
of the their lives in freshwater and part in saltwater.
is a great deal to be learned about the fundamentals of the process,"
he said. "It is even more complicated for the hatchery phase.
What works to grow one species in culture may not work at all for
another species. We have to do very basic research on growing the
fish as well as basic research on the effects of the releases."
Miss lab has been a pioneer in marine research and education in
the northern Gulf of Mexico since 1947. Institutions working with
the GCRL on the stock enhancement program are Oceanic Institute
of Hawaii, Mote Marine Laboratory of Sarasota, Fla., and Jackson