- 52 - 



substrate becomes a mixture of silt, silt-sand, and clay- 

 As the continental slope deepens into the abyssal plain 

 at depths greater than 1000 fathoms (lR30m), clay predomi- 

 nates over silt and becomes the major substrate (MAFMC, 

 1978). 



Unlike the more uniform southern portion, the shelf 

 area north of Georges Bank i^ characterized by many scat- 

 tered rises which comprisf the various fishing banks. The 

 estuarine influence of coastal rivers is absent, and there 

 are none of the canyon features which are typical to the 

 south. The northern portion is also characterized by colder 

 waters as the influence of the Gulf Stream current diminishes 

 ^nd a colder current regime becomes more predominant. 



The dominant current in the region is the Gulf Stream, 

 which forms a narrow river of v^arm water from the Gulf of 

 Mexico to the Northwest Atlantic (figure 4). In the spring, 

 a large circular flow of water around Georges Bank creates 

 the Georges Bank Eddy. The eddy dissipates in the fall, 

 when most water moves southerly over the Bank (Res. Inst. 

 G. Maine, 1974). A second eddy encompasses the entire 

 Gulf of Maine. 



Distributional charts of commercially important species 

 are included in figures 5a through 5o . These charts indicate 

 that almost every such species is present in commercial 



