Seasonal Distribution of Cod (Gadus morhua L.) Along the Canadian Atlantic Coast in Relation to Water Temperature

Abstract

Seasonal relationships between size, bottom temperature, and distribution of cod are described for the western Gulf of St. Lawrence and Nova Scotia Banks.In summer, in the western Gulf of St. Lawrence, cod are distributed from 35 to 145 m at bottom temperatures from −0° to 6 °C. They are most abundant at about 100 m where the temperature is around 1 °C. In winter they are concentrated in 130–180 m along the western slope of the Laurentian Channel at bottom temperatures from 1° to 3 °C.On the Nova Scotia Banks cod are less abundant than in the Gulf of St. Lawrence. They are found mainly around Banquereau, Middle Ground, and the northern edges of Sable Island Bank. Further to the west cod are replaced by haddock as the dominant species. Nova Scotia Banks cod are found in shallower and warmer waters than Gulf cod, both in summer and winter. In summer they are present from 65 to 110 m at bottom temperatures varying from about 1° to 8 °C. In winter they are taken primarily at 90–135 m at bottom temperatures from 2° to 4 °C.Area and depth distributions of commercial catches reflect the seasonal pattern of cod migrations and distributions demonstrated in surveys and tagging studies.