Aspects of the reproductive biology of the common Octopus vulgaris from landings in the coastal trawl and artisanal fleets in the Atlantic waters of southern Morocco

Abstract

An investigation of aspects of the reproductive biology of the common octopus Octopus vulgaris caught in the Atlantic waters of southern Morocco was undertaken in 2020. The study focused on the demographic structure and sexual maturity of O. vulgaris by sampling landings of the coastal trawl and artisanal fleets active in the study area between Sidi El Ghazi and Cap Blanc. The artisanal fleet exploited mainly medium-sized individuals (on the commercial grade ‘Mitsubishi’ scale) as T5 (>1.2–1.5 kg) to T3 (>2.0–3.0 kg), whereas coastal trawlers tended to exploit smaller individuals in size classes T8 (>0.3–0.5 kg) to T6 (>0.8–0.2 kg). The sex ratio of the catches was significantly different between the coastal trawl and artisanal fleets (p = 0.043), being in favour of males in the landings of coastal trawlers (1.14:1 M:F) and in favour of females in the artisanal fleet (0.91:1 M:F). Size at first maturity of this species in the study area, denoted by dorsal length of the mantle and weight, respectively, was 14.98 cm and 370.56 g for males, and 15.75 cm and 563.08 g for females.