BOSTON (AP) _ Lobstermen who for years have complained about small harvests off the Massachusetts coast suddenly find themselves with a glut of the succulent sea creatures.

''We have 23 tanks, wall to wall, and they're all full,'' said Steven Burns, owner of South Shore Lobster in Hingham. ''We asked some of our regular fishermen to hold some of their catch until we empty out some tanks.''

A year ago, a shortage of lobsters was pushing prices up, said Burns, whose shop sold native chicken lobster Thursday for $2.69 a pound, compared with the normal $3.99 for this time of year.

Burns said he was paying fishermen $1.75 a pound, the lowest boat price in five years.

''The ones who shop for the best price daily on the spot market - they're the ones getting hurt. I don't know where they're going to sell them,'' he said.

His firm has been buying 4,000 to 5,000 pounds of lobster daily this week, compared with 800 pounds a day a year ago.

This is the big season along the Massachusetts coast for the tasty crustacean with the snapping claws, the star attraction at clambakes and restaurants.

''It's a big glut,'' said a spokesman at Sandy Bay Lobsters in Gloucester, who declined to be identified. ''We know it's heavier now that it's ever been in recent years. It's slashing the prices.''

He said the price per pound paid to lobstermen at the dock was $1.80.

A Hingham lobsterman, who asked that his name not be used, reported there is ''a lot of infighting to get rid of lobsters, especially among part- timers'' in the lobster fishing fleet.

He said his regular dealer asked him to hold about 200 pounds of lobster - the first time he has had to hold his catch in several years.

''Nobody knows for sure why this year is so good,'' said Judy Capuzzo, who has conducted research on lobsters at Woods Hole Oceanographic Institution. ''It could go back to the year they hatched five to seven years ago. Something about that year may have been just right for development.''

''These things are hard to forecast. This could change in a week or two,'' said Brian O'Gorman, assistant marine fisheries biologist for Massachusetts. ''There's another factor here. A lot of these New England dealers do import lobsters from the Canadian Maritimes. That also has some bearing on whether there is a glut.''

At James Hook & Co., one of Boston's oldest dealers in live lobsters, Jim Lynch said the Canadian imports didn't have much to do with the surplus stock.

''There are a million different reasons,'' said Lynch, adding that dealer prices in general are down about $1 a pound. ''Historically, after the Fourth of July, it's a slower period for the next two weeks. Demand is down a bit all of a sudden.''