Circadian rhythm and activity pattern of the European spiny lobster.

CARLO PIPITONE; DANNA GIOVANNI; FABIO BADALAMENTI; GIACALONE MAXIMILIANO; JAVIER CIANCIO; ARTURO ZENONE

Barcelona

Conferencia; The Crustacean Society Mid-Year Meeting; 2017

The European spiny lobster (Palinurus elephas) is known to display acircadian rhythm of activity affectedby environmental factors like light and tide. Biological factors such as foodavailability and the presence of predators also play a role in lobsterbehaviour. A mesocosm experiment was set up in order to measure the activitylevels of sixteen adult spiny lobsters tagged with X16-mini Gulf Coast Data Conceptstriaxial accelerometers during three consecutive 24-hour treatments:Acclimation, Feeding, and Predator. Four lobsters at a time were used in eachtreatment in a tank provided with rock refuges put on a sandy bed. The firsttreatment consisted in an acclimation of lobsters in the tank. During thesecond treatment lobsters were fed with bits of anchovy. A predator (commonoctopus, Octopus vulgaris) wasintroduced in the tank for the third treatment. Using the gravitationalcomponent of acceleration data, the variance of the roll angles was calculatedas a proxy of activity level and used to draw actograms. The mean activitylevel was higher during the night with no difference between Acclimation andFeeding. During the Predator treatment the activity was lower and with nodifference between day and night. This experiment confirms the higher nocturnalactivity in the European spiny lobster when not subject to predation risk, witha clear circadian rhythm under the influence of light. The presence of apredator acted as a levelling factor that caused an overall reduction ofactivity, possibly dictated by the need of hiding inside the refuge in order toreduce the chances of encountering the predator.