II. BIOLOGY OF AMERICAN LOBSTERS 

 A. Range and Distribution. 



The American lobster occurs in varying density of 

 population from the Strait of Belle Isle (Labrador- 

 Newfoundland) in the north to the offshore waters of 

 the Carolinas in the south. Its range extends seaward 

 in several areas to the Continental Slope. The three 

 major commercial concentrations are along the Maine 

 and the Nova Scotian coasts and in the Gulf of St. 

 Lawrence (Fig. 1). A population which is being fished 

 with increasing intensity occupies the outer shelf and 

 slope of the Gulf of Maine and the offshore grounds to 

 the south. 



The most productive trapping areas are those in the 

 vicinity of ledge outcrops, glacial drifts, and talus 

 slopes. Traps set near ledges or boulders catch more 

 lobsters than traps on smooth and unbroken bottom. 

 Since lobsters appear to be primarily trapable when 

 they are hunting for food (frequently they may seek 

 shelter in a trap) the location of traps near burrows or 



other hiding places permits capture of lobsters with a 

 minimum of effort by fishermen. 



B. Environment. 



Lobsters apparently will occupy any type of 

 sediment — sand, clay, or silt — provided cover debris 

 is available for shelter. The greater the concentration 

 of hiding places the greater appears to be the concen- 

 tration of population. Except when they are foraging, 

 lobsters occupy hiding places under rocks, boulders, 

 or other bottom debris, crevices in underwater ledges, 

 or voids between submerged glacial boulders. 



Lobsters are found on both smooth and rough bot- 

 tom. The highest concentrations occur in rocky areas 

 which serve as anchorage for plants and provide cover 

 ■for many food organisms. Such systems are attractive 

 to other predators, so lobster survival in them is a 

 function of cover available. On smooth bottoms con- 

 centrations of food and predators are lower, and lob- 

 sters are more prone to move. Movements on smooth 

 bottom do not appear to represent purposive migra- 



u e b e c 



Georges • Corsoir Conyon 



Hudson Conyon 



RECENT NORTH AMERICAN LOBSTER CATCHES 

 Each Dot = 100 Metric Tons 



?^^' Cope Holleros 



Figure I.— North American average lobster landings, 1956-60. (Figure courtesy of D. G. Wilder. Fisheries Research Board of 



Canada.) 



