New rules, which go into effect for much of the East Coast next June, will allow the biggest lobsters to keep spawning.

Fishermen from Massachusetts to North Carolina are trying to keep lobster from becoming another fish story – the kind that ends up with stocks collapsing.

Borrowing a page from the thriving lobster industry in Maine, they've pushed through new rules that limit the size of the lobsters they catch. The idea is to protect the breeding stock for new generations of the shellfish. It is also a test of whether such industry efforts can protect lobster fisheries from outside threats ranging from hurricanes to illness to global warming.

Problems with lobster stocks in southern New England are a "warning sign" for lobster everywhere, says Michael Tlusty, director of research at the New England Aquarium in Boston. "It took five years for shell disease to march up the coast of Massachusetts, and now Maine has this disease right on their doorstep."

The Gulf of Maine provides 85 percent of the nation's lobster, but until a decade ago, fishermen farther south were bringing in a rising number of the shellfish. Lobster landings in southern New England almost quadrupled between 1982 and 1997. Then in the late 1990s, shell disease, hurricanes, and pesticide runoff devastated the stocks – and the catch plummeted to levels barely above those of the early '80s.

So lobster fisheries off Rhode Island and New York's Long Island Sound began pushing for catch limits that have been used for decades in Maine, says Toni Kerns, fisheries management coordinator for the Atlantic States Marine Fisheries Commission in Washington. In May, the commission approved the new rules, which take effect next June and apply to waters from southern Massachusetts to North Carolina.

The new rules will force lobstermen to throw back big lobsters – those with an abdomen more than 5-1/4 inches long – and keep only the small ones. Those limits apply to waters up to 40 miles from shore. Beyond that, the rules allow slightly bigger specimens to be caught, but the limits get tightened each year through 2010.

The reason: big lobsters are the most prolific at reproducing.

"These big lobsters are worth their weight in gold in terms of egg production," says Richard Wahle, a senior research scientist at the Bigelow Laboratory for Ocean Sciences in West Boothbay Harbor, Maine. He calls the new regulation an "insurance mechanism."

A five- to six-pound female lobster produces an average of 100,000 eggs per set – up to 20 times that of a one-pound lobster, says Robert Bayer, executive director of the University of Maine's Lobster Institute in Orono.

Even lobstermen back the idea of protecting the biggest specimens.

"They're like compound interest in the bank," says Lanny Dellinger, president of the Rhode Island Lobstermen's Association in Wakefield. "It's short-sighted to take everything you can."

Lobsters have been thriving in the Gulf of Maine in recent decades, in part because juvenile stocks are replenished by large lobsters that fishermen must throw back, says Dr. Tlusty. Gulf of Maine fishermen have long been required to throw back lobsters with abdomens longer than 5 inches.

Until now, fishermen south of the gulf had free rein to harvest big lobsters, a phenomenon that has irked lobstermen up north who want the same rules to apply to all and scientists who worry about the future of the stocks. "It's really important to manage this species as a network of populations," says Dr. Wahle.

Recent efforts south of Maine could help test whether human efforts to protect the brood stock is sufficient to allow the American lobster to withstand fishing pressures and stress factors in its habitat. Even if lobstermen learn where to draw the line, experts say they might not be able to safeguard the fisheries from environmental threats such as hurricanes and the unpredictable effects of increased ocean temperatures due to global warming. "We like to think all of our conservation measures make a difference," says Wahle. "But Mother Nature plays a huge role in this."

The size rule will not completely prohibit large lobsters from being caught in US waters, says Diane Cowan, executive director of the Lobster Conservancy, a research organization for the American lobster based in Friendship, Maine. "I think it's a step in the right direction, but the problem I have with it is that it only restricts fishing in certain areas."

The rule excludes outer Cape Cod, where large lobster are currently trapped, as well as ground fishermen who are permitted to take in up to 500 lobsters per day as by-catch. "They can still be bought and sold and marketed in every state except for Maine," Dr. Cowan adds. "You can tell fishermen not to catch large lobsters, but until it's a rule that says 'no possession' – that's the word they use in Maine – they'll still be landed."

Despite the new catch size rule, it could take years – maybe decades – for the lobster stocks in southern New England to recover, says Tlusty.

Still, lobstermen like Mr. Dellinger put their faith in the large lobsters and hope for the best. "It's important to get this fishery back to where it used to be so there's a future for the next generation of fishermen," he says. "It's going to get better."

• Christian Science Monitor Article