This study highlights for the first time individual differences in ethology and vulnerability of Octopus vulgaris
(i.e. body postures, movements and skin displays) facing passive baited
traps. Common octopus exposed to a baited trap during three consecutive
first-capture tests exhibited diverse behavioural and body pattern
sequences resembling when the octopus searches for and hunts its wild
prey. Overall, they first visually recognized new objects or potential
preys and rapidly moved out of the den, exploring, grabbing and
approaching the trap with the arms (chemotactile exploration), and
capturing the bait with the arms and feeding on top over long periods
inside the trap. Simultaneously, O. vulgaris displayed diverse
skin textural and chromatic signs, the regular pattern being the most
frequent and long-lasting, followed by broad mottle, passing cloud and
dark patterns. All individuals (n=8) caught the bait at least once,
although only five octopuses (62.5%) entered the trap in all three
tests. In addition, high variability among individuals was observed
regarding behaviour and body patterns during the first-capture tests,
which might evidence different individual temperaments or life-history
traits. Differences in behavioural responses at individual level might
have population consequences due to fisheries-induced selection,
although there is a high necessity to assess how behavioural traits
might play an important role in life-history traits of this species
harvested by small-scale trap fisheries. |