EVALUATING THE POTENTIAL FOR STOCK ENHANCEMENT OF THE BAY SCALLOP (Argopecten irradians irradians) THROUGH IMPLEMENTING LARVAL RELEASE STRATEGIES IN NANTUCKET HARBOR. *Tara Anne Riley¹, Stephen M. Heck², and Matthew C. Herr². 1, 2 The Town of Nantucket’s Marine and Coastal Resources Department, 34 Washington St., Nantucket, MA 02554
Nantucket has one of the last surviving commercial bay scallop fisheries on the east coast. We have an average of 300 commercial permit holders and around 1000 recreational permit holders per year. The landings are variable from year to year and dependent on many environmental factors that influence optimal water quality, suitable habitat, and sufficient bay scallop recruitment within each year class. Our average annual harvest for the past three years has been around 20,000 bushels with an average of 8lbs of bay scallop meat per bushel. Our recreational season starts October 1 and ends March 31(Wed-Sunday). The commercial season starts November 1-March 31 (Monday-Friday).
Over the past decade many strategies have been implemented in efforts to enhance Nantucket’s bay scallop fishery and to supplement natural production to increase the population. Due to increased environmental pressures and limited funds, the Town of Nantucket’s Marine and Coastal Resources Department implemented a new program in 2010 to evaluate releasing competent hatchery-reared bay scallop larvae into pre-selected areas in an effort to increase the chance for larval retention and survival during optimal tides and conditions. Currently, the town has gone from releasing 5 million competent larvae in 2010 to releasing 170 million in 2012. The larvae were released in areas that are in need in of restoration or habitats that have been known as great larval retention areas. Spat collection bags were deployed within the surrounding areas to evaluate recruitment. After 48 days, the spat bags were collected and the juveniles were counted and measured. Spat bag recruitment in release areas tend to indicate recruitment from a specific spawn (i.e. release) and spat collected is fairly uniform with a low standard deviation indicating a fairly uniform distribution from a localized release. Further surveys are conducted later via dive transects which indicated a significant recruitment of juveniles with very little variation or other size classes. A total of six releases with 170 million competent bay scallop larvae took place in the summer of 2012 and are currently under further evaluation. Preliminary results indicate that the larval release strategy may be an effective tool for future stock enhancement in Nantucket Harbor.