Following the die off of juvenile shellfish at the Martha's Vineyard Shellfish Group in recent weeks, there will be a summit of the minds next Wednesday at the Tisbury Town Hall. Shellfish constables, biologists, members of the Lagoon Pond Association and the Tisbury Waterways Inc. will meet at noon to talk about the next step in protecting the water quality in the pond.

Last week the Lagoon Pond solar shellfish hatchery reported losing four million juvenile shellfish. The cause of the die off, apparently due to poor water quality and harmful algae, was linked to rising levels of nutrients in the pond. Rick Karney, director of the hatchery, said the water quality was the worst he'd seen in 27 years.

Derek Cimeno, Tisbury shellfish constable, said next week's summit will "want to discuss the problems at the shellfish hatchery and look at the recent algae blooms and the juvenile shellfish kills. We are all concerned. We have to form some strategy and talk about dredging. We need to make Lagoon Pond a better and healthier pond."

Among those expected to attend will be William Wilcox, water resource planner for the Martha's Vineyard Commission, and Mike Syslo, 18-year director of the Massachusetts state Lobster Hatchery in Oak Bluffs, which stopped its pumps last year due to state budget cuts. Mr. Syslo recently became a regional shellfish biologist and is responsible for doing water testing in all Vineyard coastal ponds.

Out of next Wednesday's meeting, Mr. Cimeno hopes there will be a renewed effort to increase circulation in the Lagoon. Two sand bars - one off Hines Point and a second off the Sailing Camp Park in Oak Bluffs - - are constricting water circulation.

Mr. Cimeno said he has been working with a firm on a dredging plan for the town. Even without the hatchery die off, dredging was likely to become an issue when a planned reconstruction of the Lagoon Pond drawbridge gets underway.

Charlie Blair, harbor master of Edgartown, met with Mr. Karney on Sunday and talked to him about the town of Edgartown's dredge, wondering if there was a way the town might help. Mr. Blair said the news from the shellfish hatchery is a wakeup for the whole Island. "We need to protect the water quality of the ponds that are still fine," he said. He said he is looking at a lot of different ways beyond dredging to protect highly valued shellfish beds in his town.

Mr. Syslo said yesterday he is concerned that the public has formed some misconceptions about the shellfish hatchery die off. Shellfish harvesting, for example, is safe in open areas of Lagoon Pond; adult shellfish are okay throughout the pond.

Lagoon Pond used to have fecal coliform issues; it does not appear to now.

Mr. Syslo also said he thinks the die off at the shellfish hatchery may be linked to the shellfish being stressed by being in an undersized hatchery.

He also questioned the interpretation of the dissolved oxygen results in areas of the pond defined as "dead."

Mr. Karney agreed it is important to be clear that the problems of Lagoon Pond concern a rise in nutrients, not bacteria such as fecal coliform.

The rise of nutrients feeds algae that will kill the pond and promote algae growth, he said.

In short, nutrient loading is a different kind of sign that human's presence is bringing down the water quality of the pond. A perfectly functioning septic system will leach nutrient- rich water into the pond; the rise in houses in the watershed and use of fertilizers on lawns is an issue.

"Nutrient loading is very severe. That is what kills the pond, eventually. There is a clear indication the animals are suffering from no oxygen. They don't call those areas dead water for nothing," Mr. Karney said.

Mr. Syslo and Mr. Karney agree better circulation is important to saving the pond.

Mr. Cimeno said there are adult bay scallops in the pond and now everyone is wondering whether they will make it through the summer and bring about a fair to good harvest in the fall. Last winter, shellfishermen had a poor bay scallop season but found plenty of seed for the coming year.