Daily increments in statoliths indicate that both male and female market sq
uid (Loligo opalescens) mature as early as 6 months after hatching. An anal
ysis of 192 statolith pairs revealed maximum ages of 238 days for females a
nd 243 days for males during 1998. These ages indicate that market squid ma
y be a semiannual species and that spawning peaks may occur twice in a cale
ndar year. Growth rate derived from size-at-age information was best descri
bed by a linear equation, with no difference between sexes.