Growth of Octopus mimus (Cephalopoda, Octopodidae) in wild populations

A total of 6171 specimens of Octopus mimus was collected from the commercia l small-scale fishery in northern Chilean waters (off Iquique) between Janu ary 1991 and March 1992. The animals were grouped by sex, size and month fo r modal progression analysis (MPA). Total length of the animals ranged from 24 (66 g) to 107 cm (4358 g) for males and from 28 (63 g) to 115 cm (3714 g) for females. There were no significant differences in the length-weight relationship between sexes except in summer. The size structure of the expl oited population of O. mimus is rather complex and MPA indicated six sub-an nual cohorts for males and five for females. Instantaneous relative growth rate (G) in total body weight varied from 0.29% to 1.37% d(-1) and from 0.2 3% to 1.78% d(-1) for males and females, respectively. Seasonality and wate r temperature affected G in both sexes. Differences in G among sub-annual c ohorts within the same season were found and it was observed that G tended to decrease with size. (C) 1999 Elsevier Science B.V. All rights reserved.