Analysis of the Biological and Demographic Parameters of Northern Sand Lance, Ammodytes dubius, from the Newfoundland Grand Bank

Biological characteristics and population dynamics of northern sand lance (Ammodytes dubius) population on the Grand Banks were investigated in the period 1968–79. Sand lance were distributed mainly in the shallower areas of the Grand Banks, particularly in the northeast and southeast areas. Through an examination of reproduction parameters I conclude that spawning occurs principally during the period November–January. Growth rates of Grand Bank sand lance are within the range of those described for the Scotian Shelf and are well correlated with temperature variations. Abundance indices, derived from groundfish surveys, indicate a substantial increase in abundance since the 1960s, and this increase is attributable to increased recruitment and reduced natural mortality. From correlation analyses I suggest that the decline in the Grand Bank population of Atlantic cod (Gadus morhua) may be responsible for the reduced mortality rates and increased abundance of Grand Bank sand lance during the 1970s.