Variation in the growth of larval and juvenile snapper, Chrysophrys auratus (Sparidae)

Abstract

For many fish species, growth and mortality of larvae are closely coupled, with faster-growing larvae generally experiencing higher survivorship in the plankton, which may lead to higher recruitment. Using back-calculated growth trajectories derived from otolith increments we used the modified Fry model to estimate the growth rate of larvae and early juveniles of the commercially important sparid, Chrysophrys auratus, at four sites around northern New Zealand. Back-calculated growth rates were used to test the hypothesis that fish with a short pelagic larval duration (≤20 days) grew faster than did fish with a long pelagic larval duration (>24 days) during both the larval and juvenile periods. At three of the four sites, fish with a short larval duration grew significantly faster during the larval period, and these larvae generally continued to have a larger size-at-age as juveniles up to 70-day-old. Growth rates for both the larval and early juvenile period were also found to vary significantly among the four sites and were found to be unrelated to differences in water temperature. Localised variation in early growth of C. auratus among sites may be important in helping explain differences in their contribution to the recruitment to C. auratus populations.