The director of the Martha's Vineyard Shellfish Group said yesterday that nearly four million healthy juvenile shellfish under culture at his Lagoo

Leaching nitrogen from residential households remains the single biggest threat to the water quality of Lagoon Pond, according to a recently completed water quality study. In a report delivered to the Lagoon Pond Association, its author found significant increases in nitrates entering the pond. The report is based on a series of water samplings conducted last summer.

Bruce Poole of SP Engineering Inc.