Lobsters on a roll
New research reveals that lobsters are too smart for fishermen's traps - they're dining and going home.
Down on the ocean bottom, marine biologist Bob Steneck seems to be finding a lobster under just about every stone.Skip to next paragraph
Subscribe Today to the Monitor
Mr. Steneck reveals them hiding under kelp fronds, amid fields of round rocks dumped here by ancient glaciers, and in little lobster fox holes dug into the sand.
Lobsters are everywhere, including the inside of a lobsterman's trap nearby. One drives a small crab away from the bait-filled bag hanging in the trap and resumes eating. Two others have dug burrows under the trap and wait patiently for their turn to dine.
Here lies the great lobster mystery. For nearly three decades, federal fisheries managers have warned that the lobster stock is overfished and faces imminent collapse. But instead, the annual lobster catch has exploded, from 20 million pounds in the '70s and early '80s to around 50 million pounds today, and scientists like Steneck see little evidence that fishermen are hurting the lobster population.
"Lobsters may be globally unique in that their population keeps growing despite high rates of exploitation by fishermen," says Steneck, who studies the tasty crustaceans at the University of Maine's Darling Marine Center in Walpole.
But scientists are beginning to get a handle on why lobsters are thriving in the face of the sort of overwhelming fishing pressures that have devastated cod, haddock, urchins, and other species in the northwest Atlantic.
Their discoveries are turning traditional fisheries management assumptions on their head, and appear to vindicate lobstermen's long-standing assertions that they have little effect on lobster population.
Take lobster traps themselves. Scientists and lobstermen generally assumed that the box-shaped traps were pretty effective snares. Lobsters enter the traps through a funnel-shaped opening and, after dining on bait inside, were thought to have great difficulty finding their way back out through the narrow end of the funnel.
Turns out, that's completely wrong, and University of New Hampshire zoologist Win Watson has the videotape to prove it.
Curious as to how effective traps were, Professor Watson attached an underwater video camera to a standard trap and dropped it down to the seafloor off Portsmouth, N.H. Given that hauled traps usually contain only a handful of lobsters, Watson expected the tape would show a modest number of lobsters approaching the trap.
But when Watson's team looked at the first time-lapse video, they were totally stunned by what they saw. "The numbers of lobsters were just amazing," Watson recalls, with lobsters scuffling and fighting over the trap. "It looked like an anthill."
But the biggest surprise was that the lobsters were happily wandering in and out of the traps at will. On the videos, lobsters of all sizes crawled in and out of the funnel-shaped entrance as they pleased. The biggest impediment they faced were other lobsters, which did their best to chase newcomers away from the bait. Only 6 percent of the lobsters that entered the trap failed to find their way out again. (To watch the video, go to http://zoology.unh.edu/faculty/win/lobster%20ecologyfisheries/ltv.htm.)
Lobstermen who have seen the video have been just as surprised. "It's pretty discouraging to think that here we, as intelligent human beings, have been trying our best to harvest this thing that has no brain to speak of and they're outsmarting us," says an amused Pat White of the Maine Lobstermen's Association.
"But it may be that part of the success of our fishery is due to the fact that our traps are as inefficient as they are," says Mr. White, who lobsters out of York, Maine.