Atlantic Fisheries Research Document 1996/069

Growth and condition of cod in subdivision 3Ps as determined from trawl surveys (1972-1996) and sentinel surveys (1995)

By G.R. Lilly

Abstract

The growth and condition of cod in Subdivision 3Ps were monitored by sampling catches during winter-spring research bottom-trawl surveys in the offshore in 1972-1996 and sentinel surveys in the inshore in 1995. In the offshore, length-at-age peaked in the mid to late 1970s and varied with no trend (younger ages) or declined slightly (older ages) during the past decade. Condition, as measured by both gutted body weight and liver weight relative to length, was low in fish sampled during the 1993-1996 surveys. However, it is not clear that the values were below normal, because the 1993-1996 surveys were conducted in April when condition is near the low point of the seasonal cycle, and only one of the earlier surveys was conducted at about the same time. The condition of fish sampled from the sentinel surveys varied seasonally and spatially. The quantity of food in stomachs of cod sampled during the sentinel surveys was generally low. A dramatic increase in stomach fullness occurred in July when the cod fed on capelin. Liver index reached a peak at that time.

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