Alabama researchers look at aquaculture alternatives

On Sept. 11, 2002, juvenile red snappers raised in captivity were released into the Gulf of Mexico. The young snapper produced by Auburn University scientists working at the Marine Resources Claude Peteet Mariculture Center in Gulf Shores were part of a study to determine habitat use and fish movements. Red snapper are one of several species of reef fish caught around bottom structures in the Gulf of Mexico. Young juveniles are rare around large reefs but are more common around micro-habitat, such as patches of old oysters reefs exposed when sands shift over the Gulf’s floor.

Scientists have found that this type of habitat may be a critical link in the life history of red snapper. To better understand this phase in the life of red snapper, AU Associate Professor of Fisheries and Allied Aquacultures Steve Szedlmayer and his staff built a set of artificial reefs from oysters shells in the Gulf the and stocked the captively-raised juvenile snapper to determine how the young fish used such reefs for habitat and food.

Hatchery-produced fish are a basic tool used to understand the biology of wild fish. Hatchery-produced fish can be marked and released into the wild at specific times and places. When they are recaptured, estimates of growth, mortality and overall population size can be made. Ron Phelps, professor of fisheries and allied aquacultures at Auburn, is leading the study to raise young snappers in captivity for use in such research.

When concerns about declining red snapper populations first surfaced more than 20 years ago, scientists working in the Gulf of Mexico attempted to raise red snapper in carefully controlled settings. Their efforts were thwarted until 1996 when Phelps’ research team became the first to successfully produce juvenile red snapper in a hatchery setting. The techniques they refined are now being used by other hatcheries and scientists along the Gulf Coast, including the Gulf Coast Research Laboratory in Ocean Springs, Miss.

Rearing red snapper is a challenge in part because so little is known about how they develop from hatchling to juvenile stages and what they require as food. Phelps and his staff focused on providing a more natural setting and on producing a higher quality fertilized egg. They also concentrated on developing appropriate feeds that promote high survival rates of newly hatched snapper larvae and establishing protocols for efficient production of juvenile red snapper.

Much of the work has been done at the Claude Peteet Mariculture Center, a facility operated by the Marine Resources Division. Brood fish are captured out of the Gulf and brought to tanks housed in specially-made greenhouses at the Center. There they are spawned and the fertilized eggs are collected and nurtured until they hatch into larvae. The larvae are then cultivated until they reach about three months in age, at which point they can be released into the Gulf.

Knowledge gained from these studies provides a better understanding of the basic biology of red snapper and, in turn, allows improved management regulations of wild stocks. But the research may also lead to a new enterprise in Alabama–red snapper "farming."

"The development of practical techniques for spawning and culture of red snapper may provide an alternative source of this fish through aquaculture (fish farming), thus reducing the commercial fishing pressure on wild stocks," explained Phelps. That, in turn, may mean more fish are available for sport fishers.

Similar work has been done in southern Europe with sea bream, which are now farmed in a multi-million dollar industry. Red snapper, it appears, is a prime candidate for such a program.

"Snappers quickly adapt to captive conditions and can become quite tame," said Phelps, explaining why red snappers are well suited to captive breeding programs. In fact, red snapper can become so tame that they will stick their heads out of the water looking for feed, a behavior rarely seen in marine fish species.

"From the juvenile stage on up, snapper are a desirable aquaculture species," Phelps continued. "They can consume an artificial diet well and convert it reasonably well. They're innately curious and they handle well, so they have a lot of potential for aquaculture."

According to R. Vernon Minton, Marine Resources Division director, red snapper already is big business in Alabama. Though Alabama has only four percent of the U.S. Gulf of Mexico coastline, recreational anglers harvest approximately 35 percent of the four million pounds of red snapper landed recreationally each year.

Minton added that Alabama currently is home to more than 100 charter and party boats that target the red snapper fishery. The economic impact of the charter boat fleet alone in Alabama is estimated at more than $60 million per year, which does not include the income from other sectors of the sport and commercial red snapper industry.

To maintain this important fishery, a much better understanding of the biology of red snapper is needed. Auburn University will continue to take a two-pronged approach to helping to preserve this resource. Phelps’s team will concentrate on the reproduction and the larval rearing of red snapper in the hatchery, while Szedlmayer’s group will focus on the reef populations and their biology.

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