Evidence of Iteroparity in Jumbo Squid Dosidicus gigas in the Gulf of California, Mexico

The jumbo squid (Dosidicus gigas) has been considered a species with a semelparous life history, and this assumption has been erroneously adopted without histological evidence. Recent studies suggest that this species can spawn more than once during its life span. To identify the reproductive strategy of jumbo squid, qualitative and quantitative analyses were used in this study. Biological data were collected fortnightly from March 2008 to November 2009 off the coast of Santa Rosalía, Baja California Sur, Mexico. The histological analyses showed five stages of development: previtellogenesis, vitellogenesis, postvitellogenesis, spawning, and postspawning, with the simultaneous presence of oocytes at different substages. These results were confirmed by the presence of multiple cohorts of oocytes at each ovarian stage. Analysis applied to resting females of D. gigas confirmed that the postovulatory follicles were simultaneously found with previtellogenic oocytes denoting the ovarian recovery. The presence of postovulatory follicles at all ovarian stages and in individuals throughout the mantle length (ML) structure (from 32 to 82 cm) was an indicator of multiple spawning events. During 2008 and 2009, four ML groups (41.2, 48.5, 55.2, and 68.5 cm) and threeMLgroups (39.9, 47.8, and 53.9 cm) were observed, respectively. In conclusion, the evidence of postovulatory follicles in resting females of D. gigas indicates that the reproductive strategy of jumbo squid is iteroparity.