GROWTH OF JUVENILE PACIFIC MACKEREL, SCOMBER JAPONICUS IU THE GULF OFCALIFORNIA

The otolith microstructure of juvenile (0-year) Pacific mackerel, Scom ber japonicus, was examined to derive estimates of age, growth, and ba ck-calculated hatching date distributions. Juveniles were collected fr om the Gulf of California between March 1990 and February 1996. Estima ted ages of juveniles ranged from 27 to 111 days (31 to 162 mm SL). A Gompertz growth model provided a good description (r(2) = 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 1 10 days old was 1.13 mm d(-1). The back-calculated hatching date distr ibutions showed that spawning occurs from November to May.