Kodiak researcher happy with crab voyage

Posted: Thursday, July 11, 2002

KODIAK (AP) -- A National Marine Fisheries Service crab research scientist said time recently spent on the research vessel Atlantis was a dream come true.

Dr. Brad Stevens took part in the three-week voyage paid for by the National Oceanic and Atmospheric Administration's Office of Ocean Exploration. The trip, which began in Astoria, Ore., had diverse objectives, including exploration of underwater mountains, called seamounts.

On board was the manned submersible vessel ''Alvin,'' the same deep-diving research submarine that took part in the discovery and exploration of the Titanic.

Stevens' primary goal was to look for habitats of juvenile crabs on seamounts.

''We covered the habitats of adult crabs on a previous exploration of Patton Seamount in 1999, but we weren't able to find juvenile crabs on that cruise because of the amount of effort it takes,'' he said. ''The plan this year was to pick up where we left off and focus on juvenile habitats.''

The exploration started on Murray Seamount. After several dives without finding juvenile crabs, the researchers moved to Patton Seamount. They found juvenile crabs and picked up a few species that they had seen before.

''Golden king crab was our primary objective. Scarlet king crab was the secondary objective and third was what we call the large clawed spider crab, which has no common name,'' he said.

''These were the most abundant crabs we saw, and the easiest to catch,'' he said. ''Taking advantage of that, we built a trap and dropped it in 2,000 meters (6,600 feet) of water with cat food for bait, which I brought along specifically for that purpose,'' he said.

The cat food worked well, Stevens said.

''We brought up over 20 spider crabs on that dive. I was hoping we could keep them alive to learn something about them, but they didn't survive due to temperature and handling.''

He was able to bring in a couple of mating pairs of golden king crabs and is hoping they will extrude new clusters of eggs in the Fisheries Research Center laboratory at Kodiak. He will study how long it takes embryos to develop.

An in-depth analysis of videotapes of crabs taken on Alvin dives is an integral part of Stevens' follow-up work.

''The work I did with red king crab shows that they only settle in very specific kinds of habitat. If they don't have that, they won't settle down. They will keep swimming until they molt.''

Most of Stevens' research is focused on essential fish habitat and what that means for different species.

''Essential fish habitat needs to be protected from degradation and destruction,'' Stevens said. ''Habitat is the most important thing for maintaining fish populations.''

Trawling is most often cited as the fishing style with the greatest impact, he said. Stevens said seamounts are a good place for exploration because in most cases fishing has not affected that environment.

The Atlantis left Thursday and is working its way south for another week of diving and exploration.

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