Atmospheric forcing on lobster post-larvae settlement
Andrew J. Pershing, Gulf of Maine Research Institute, Portland, ME; and R. Wahle and P. C. Meyers
Lobstering is one of the nation's most lucrative fisheries, and understanding the dynamics of lobster populations is key to maintaining the industry. On Damariscove Island, lobster larvae settlement is much greater on the side perpendicular to prevailing winds, suggesting atmospheric forces could account for interannual variability. This study looks to find the climatic conditions that are associated with lobster larvae settlement.
Lobster settlement data from eleven regions across New England were compared to monthly geopotential height, wind field, and temperature data extracted from NCEP North American Regional Reanalysis dataset. Geopotential heights in September were the best indicator of lobster settlement. The strongest correlations were found in northern Massachusetts (r=0.92, p<0.001) and in New Brunswick (r=0.71, p=.005). The correlation between settlement and geopotential height was weaker between these sights, but still significant (r=0.58, p=0.019). Settlement in Rhode Island occurs earlier in the summer, and the best correlation with geopotential heights was from July (r=0.62, p=0.014). Years of high settlement are characterized by onshore winds or onshore Ekman transport. Northerly winds over New England, rotating cyclonically to southwest winds over the Atlantic, prevail for years with poor settlement.
The specific driver connecting geopotential height to lobster settlement is still not clear. Geopotential height fields will affect surface winds, forcing ocean surface currents and Ekman transport. Clear skies associated with high pressure would enhance the sea breeze, possibly further driving lobster larvae to the shore.
Poster Session 1, Student Conference General Poster Session
Sunday, 20 January 2008, 5:30 PM-7:00 PM, Exhibit Hall B
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