Input of Calanus finmarchicus into the Gulf of Maine through the Northeast Channel of Maine during winter

C. Ashjian, E. Durbin, and C. Flagg

The Northeast Channel is a potential route for input of populations of Calanus finmarchicus into the Gulf of Maine, either from upper water column populations advected off of Browns Bank to the north or from populations resident at depth in the Slope Water. Broadscale surveys of the vertical distributions of plankton populations, accompanying hydrography, and water column velocities have been conducted on Georges Bank at monthly intervals during the winter and spring of 1995-1999 as part of the US GLOBEC Georges Bank program. Data from 13 cruises were examined to determine seasonal changes in the abundance of Calanus in the Slope Water and the direction and magnitude of transport of Calanus through the NE Channel during these months. Calanus abundances in Slope Water were greatest during the late spring-early summer. Preliminary calculations show that Calanus usually are input into the Gulf of Maine along the eastern side of the NE Channel, but that outflow occurrs along the western side and that the flux of Calanus into the Gulf of Maine through the NE Channel is variable.