AN INDIVIDUAL-BASED ANALYSIS OF THE VARIABILITY OF EGGS AND THEIR NEWLY-HATCHED LARVAE OF ATLANTIC COD (GADUS-MORHUA) ON THE SCOTIAN SHELF

We assessed the seasonal pattern of size variation in cod eggs on the Scotian Shelf region of the Northwest Atlantic during the period March 1991 - May 1993. Cod eggs were present from October to May during the surveys. Spawning was not strongly bimodal. There was a dominant autu mn peak, in contrast to the historically dominant spring spawning. Egg diameter varied seasonally. Seasonal temperature patterns explained 5 2% of the variation in egg diameter. By incubating the eggs on-board s hip, we also assessed the seasonality of the standard length (SL) of l arvae that hatched from these eggs. Larval SL also varied seasonally. Egg diameter and SL were significantly correlated, but the correlation was weak (r(2) = 0.3). However, the strength of correlation was consi stent with laboratory estimates based on individual data. The results suggest that previous estimates of the egg size - larval size correlat ions are inflated. Temperature exerted a significant effect on both eg g diameter and larval size, and is hypothesized to be the agent respon sible for the observed seasonal variation.