New Findings on the Behaviour of the Horned Octopus Eledone cirrhosa in Captivity

Abstract

A total of sixteen individuals of horned octopus Eledone cirrhosa were caught using creels by a vessel of the small-scale fishery operating in the Ria of Vigo (NW Spain). Captures took place on the west side of the Cies Islands (Galician Atlantic Islands Maritime-Terrestrial National Park) in March 2013 between 60 and 70 m depth. All the octopuses were females, ranging 355–950 g in body weight. Animals were kept alive and subsequently transferred to open seawater system. Observations under confined conditions resulted in several behavioural events, summarized as follows: i) visual attack sequence was described and found to be similar to that exhibited by Sepia sp., which involves three main phases: attention, positioning and seizure, ii) after a time of confinement, females spontaneously start to spawn in the artificial dens arranged inside the tanks, although eggs were unviable, and iii) females spawn within a shelter, inside which they remain during eggs development, and block the entrance with stones and other materials they find nearby the burrow. This behaviour has been observed for the first time in E. cirrhosa. These new findings are discussed and compared with previous literature.