A curtain call for colossal crustaceans

A 10, 12, or even 18-pound lobster? They exist, and this may be the last season to really enjoy them.

Legal Sea Foods owner Roger Berkowitz says his restaurants are stocking more lobsters between five and 15 pounds this summer, compared to past years. Lobsters of that size typically are available only in early spring, but since the months of April and May were colder than average, the big ones appeared on the menu later in the season, Berkowitz says.

Jim Piper , a retired California pilot in Boston on a vacation, said when it comes to lobsters, the bigger the better. He prefers 12 pounds or more.

"It's an old wives' tale that bigger lobsters are tougher," he said. "They all taste the same."

After this year, huge lobsters may be harder to find because of new rules set by the Atlantic States Marine Fisheries Commission that will in the next few years prohibit fishermen from harvesting lobsters with bodies longer than 6 3/4 inches from Massachusetts waters. The reason: The bigger the lobster, the more eggs and offspring they produce. Fish out too many big ones, and the two-pounders you have for dinner could disappear.

The commissioners are "trying to maintain a robust brood stock by leaving the larger lobsters in the ocean," said Tina Berger , a spokeswoman for the commission , which regulates fishing in waters from Maine to Florida .

The relationship among a lobster's size, age, and reproductive capacity is a function of simple math. A one-pound lobster is probably between five and seven years old and a female that size can carry about 10,000 eggs. If it lives long enough to reach nine pounds, which could take 20 years or more, the same lobster can carry about 100,000 eggs.

Put another way, an older, larger lobster might produce 10 times more eggs than a smaller one. And a lobster's chance of making it to the ocean floor, where it can hide from fishermen and other predators, increases as it gets older.

"Once an animal gets so big, if you can protect it, it's better for the state of the fishery,' said Michael Tlusty , director of research at the New England Aquarium .

To offer that protection, the fisheries commission will prohibit harvesting of lobsters with a carapace, or abdomen, of 5 1/4 inches or longer, out of waters up to three miles off the coast of Massachusetts beginning next June. In waters between three and 200 miles off the coast -- which is where lobstermen say bigger lobsters tend to live -- lobsters with bodies of 6 3/4 inches or longer will eventually be off limits.

Tlusty said it is difficult to estimate how much a lobster might weigh just based on the length of its carapace because more than 80 percent of its weight can be in the claws and tail. Two lobsters can have carapaces of the same length but the one with smaller claws would weigh significantly less.

So far, the new rules don't seem to be bothering many people who rely on lobster for a living.

"We're in favor of it," said Bill Adler , executive director of the Massachusetts Lobstermen's Association . The group supports the change because it wants to make sure that there are enough lobsters around to catch and sell for years to come, he said. Besides, Adler noted, humongous lobsters are somewhat impractical.

"By the time you get up to these huge things, it's got to be a special event for somebody to want one of those things," he said. "Because they're harder to sell, the dealers pay less for them."

At James Hook & Co. Seafood in downtown Boston, the smaller lobsters are more popular, even though they cost more per pound. Lobsters weighing between one-and-a-half and seven pounds cost $10.99 per pound . Bigger ones cost $6.99 per pound but you end up spending more because they weigh more.

Not everyone thinks big is better.

"I would never buy a lobster that big," said Laura Miller , a New Yorker who stopped by James Hook recently while visiting Boston. "Aren't they supposed to get tougher as they get bigger?"

That's a common misperception, said James Hook , the third-generation owner of the lobster retailer. Most people have never seen a 10-pound or 15-pound lobster, let alone cooked one, he said. So people tend to over or undercook them.

Hook hands out a guide to customers that recommends cooking a one to one-and-a-half pounder for 10 to 12 minutes , and a 10-pound to 15-pound lobster for between 40 and 50 minutes.

Legal Sea Foods' Berkowitz said at his restaurants, it's typically tourists or executives hosting large parties that snap up hefty lobsters.

"Certainly large lobsters don't sell in the suburbs," he said. "People who are on vacation, celebrating, or entertaining business associates, say a Boston company entertaining Japanese businessmen. The Japanese go crazy over large lobsters, so sometimes they'll get two to three per table."

Keith Reed can be reached at reed@globe.com.