Growth of juvenile Pacific mackerel, Scomber japonicus in the Gulf of California

The otolith microstructure of juvenile (0-year) Pacific mackerel, Scomber japonicus, was examined to derive estimates of age, growth, and back-calculated hatching date distributions. Juveniles were collected from the Gulf of California between March 1990 and February 1996. Estimated ages of juveniles ranged from 27 to 111 days (31 to 162 mm SL). A Gompertz growth model provided a good description (r² = 0.85) of the length-at-age relationship. The maximum daily growth rate calculated was 1.91 mm d^-1 for 44 day-old fish. The average growth rate up to 110 days old was 1.13 mm d^-1. The back-calculated hatching date distributions showed that spawning occurs from November to May.