Aspects of the reproductive biology of the North Pacific giant octopus (Enteroctopus dofleini) in the Gulf of Alaska

Abstract

In 2011, octopuses in the Gulf of Alaska were removed from the “other species” group and are now managed by the North Pacific Fishery Management Council as a complex that includes all octopus species within this region. Management of this complex includes the specification of annual catch limits and overfishing limits. Understanding the life history of octopuses is important for establishment of appropriate management strategies. The North Pacific giant octopus (Enteroctopus dofleini) is the most abundant octopus species found on the continental shelf and dominates the commercial catch of octopuses within the Gulf of Alaska. Specimens of the North Pacific giant octopus were obtained from charter operations, commercial fishermen, and scientific surveys within the Gulf of Alaska. This species has a protracted reproductive cycle and peak spawning occurs from winter to early spring months. In the Gulf of Alaska, this species matures at weights from 10 to 20 kg; weight at 50% maturity is 13.7 kg (95% confidence interval [CI]=12.5–15.5 kg) for females and 14.2 kg (95% CI=12.6–15.9 kg) for males. Estimates of fecundity for this species range from 41,600 to 239,000 eggs per female and average fecundity is estimated at 106,800 eggs per female. Fecundity was positively related to the weight of the female (n=33, P<0.001). Determination of reproductive parameters is necessary to assess the vulnerability of octopuses within this region to overfishing and to establish appropriate management strategies for this species group within the Gulf of Alaska.