Growth Comparison between Juvenile Atlantic Mackerel (Scomber scombrus) from the Two Spawning Groups of the Northwest Atlantic

Abstract

We compared daily growth patterns of otoliths of juvenile Atlantic mackerel (Scomber scombrus) younger than 91 d between the two spawning groups that occur in the Northwest Atlantic using a Gompertz model to determine whether it is possible to differentiate these groups on the basis of otolith microstructure in a mixed fishery. The growth curve parameters for the northern and southern groups, respectively, were 36.2 versus 39.7 d for the inflection point (t0), 0.047 versus 0.040 for the instantaneous growth rate (k) when t = t0, and 169.1 versus 192.5 mm for the asymptotic length at the end of the first summer of growth (L∞). These growth curves do not significantly differ (likelihood ratio test, P > 0.5). It therefore appears that the otolith microstructure corresponding to the first summer would not allow identification of the group of origin.