EVIDENCE OF DIFFERENT STOCKS OF MACKEREL SCOMBER JAPONICUS

Samples bf the commercial catch of mackerel Scomber japonicus from Ens enada, Vizcaino Bay, Magdalena Bay and the Gulf of California were ana lyzed to show biological evidence that supports a hypothesis of two st ocks of mackerel. This evidence is the reproductive period, maturity c ycle, deposition pattern of the otolith bands, length (L(50%)) and age (E(50%)) of reproduction and composition by length and age of the cat ch. Two stocks were identified, one that is distributed from southern California to Vizcaino Bay and the other in the Gulf of California. Bo th stocks overlapped at Magdalena Bay, which seems be a feeding site w here young individuals that have not been recruited to the spawning st ock inhabit.