Spatial and temporal variation in size at maturity for female American lobster in Nova Scotia

Using the development stage of cement glands to predict spawning, maturity ogives were constructed for six fishing ports in eastern Nova Scotia. The size at which 50% of females attained maturity (L-50) and the ogive slopes were compared between locations and years. Among ports within years, 21 of 25 L-50 pairs were significantly different, while only 5 of 24 slope pairs were different. These results fill a geographic gap and indicate that most of the areas should not be grouped when calculating egg production. Comparing among years within ports, most significant differences were again for L-50 rather than slopes. In two ports, the change in the ogive among years gave a 2- or 2.4-fold change in eggs per recruit and a 2.9- or 5-fold change in the percentage of females that reach maturity by the legal minimum size. On a larger scale, L-50 was intermediate in Newfoundland, consistently low throughout the southern Gulf of St. Lawrence, abruptly increased on the outer coast of Nova Scotia into the Bay of Fundy, and again intermediate inshore and offshore New England.