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Marine biologists look at hatcheries for 2 fish

Published on NewsOK Modified: January 26, 2013 at 9:22 am •  Published: January 26, 2013

"We're only releasing 6,000 a year. You wouldn't expect that to even show up. But if we can do that with 6,000 fish, think what I could do with 100,000 fish a year. We just cannot rear that many snook yet."

Blaylock said he uses fish taken in routine state and USM catches to assess fish populations because he knows exactly where each is caught. The scientists use magnetic wands to check for the tags. They've occasionally thought they'd found a hatchery fish only to discover it was a wild fish that had swallowed a hook.

Blaylock said USM's hatchery costs about $2 million a year to operate. It comes from a combination of federal grants, mostly from one agency or another within the National Oceanic and Atmospheric Administration, and state grants through programs including Tidelands and the Coastal Impact Assessment Program.

Texas gets millions of dollars a year for hatchery research from that state's branch of the Coastal Conservation Association, a sports fishing group, but "Mississippi isn't quite as rich as Texas, so we don't get as much direct financial support," Blaylock said.

He said he's working with red snapper and speckled trout because they're among the most popular fish in the Gulf.

Overfishing brought annual fishing quotas on red snapper, though those have risen from 4 million pounds in 1991 to just more than 8 million pounds last year, when NOAA said overfishing had ended and the population is rebounding. A new stock assessment is under way. The quotas are divided between commercial boats and recreational anglers.

Hatcheries will never eliminate fishing restrictions, Leber cautioned. "We need stronger laws than ever," he said.

Specks are not considered threatened but are "under enormous fishing pressure" because of their popularity, Blaylock said.

Since 2004, when the seatrout project started, "we've learned a lot about the culture of the fish, the tagging technology. We've developed the ability to identify all of our hatchery fish genetically. But we have not yet figured out how to efficiently catch the fish after we release them," he said. Finding ways to do that is part of the project and a graduate student's thesis topic, he said.

The student is studying whether gill nets, seines, traps or trawls are best at catching the fish while they're still small. "He's looked at some sonar tracking to try to track them as they leave to know where they go to try to sample them," Blaylock said.

But at least specks will spawn in tanks and eat easily raised plankton, though the hundreds of thousands released by USM are just a drop in the ocean.

Red snapper are a far tougher problem. Researchers must collect eggs from wild-caught females because they are still trying to figure out how to get the fish to spawn in captivity, Blaylock said.

Once hatched, they have a problem in common with snook: Their mouths are so tiny they can't eat brine shrimp or easily grown plankton called rotifers. They need the newly hatched larvae of even tinier and harder to raise creatures called copepods.