Cuttlefish spawning and visually mediated entry into basket traps

Abstract

The behavior of the cuttlefish Sepia esculenta near basket traps was observed in the field and in the laboratory in order to analyze the capture process of basket traps. In the field, cuttlefish spawned both during the day and the night and mainly outside the traps. This finding negates the conventional idea that the entry of cuttlefish into traps is motivated by spawning. Cuttlefish entered and exited from the trap in a straight movement with the arms first, as in feeding. No cuttlefish touched the trap during these movements, which means that the reaction of cuttlefish to traps is mediated by vision. Cuttlefish inside the trap moved very slowly, not evasively, and they remained inside for at least 2 days. This behavior indicates the existence of an attractive stimulus within the trap. In laboratory tanks, individuals repeatedly entered the trap. Because the average length of stay of six cuttlefish in the trap in the first entry (6 h 18 min) was less than in the sixth entry (8 h 19 min), exploratory behavior cannot explain the behavior of cuttlefish entering basket traps.