Publication Abstract

The Effect of Previous Experience on the Motivation to Burrow in Early Benthic Phase Lobsters (Homarus gammarus (L.))

J.F. Wickins and J. Barry

The competence with which hatchery reared juveniles construct burrows following release in stock enhancement programmes is likely to be a significant factor governing their subsequent survival. The possibility that previous burrowing experience might be of benefit has been considered but appears not to have been fully reported. The effects of habitat features, experience, lobster size, and disturbance on burrowing behaviour of hatchery reared H. gammarus (instars 7 to 12; range 7.5-27 mm CL) were investigated in the laboratory by counting their attempts to burrow into friable substrates (graded sand to gravel). Lobsters were observed over three discrete, 3 day periods between which they were transfered to new, but identical, environments. Initially, the lobsters burrowed actively but while this declined within each 3 day period, activity was renewed at each transfer to a new tank containing the same habitat features. Lobsters appeared to learn not to burrow under small tiles that would collapse into the burrow chamber. Disturbance (flashing lights) increased attempts to burrow in the largest lobsters tested but only on the lobster's first day in a new environment. Overall, all individual lobsters within the size range tested showed very similar motivation to burrow despite having no previous burrowing experience. The results imply that 4 to 6 week old hatchery reared juveniles could cope with selected seabed environments as well as the 3 month old juveniles released during recent UK stock enhancement experiments.

Reference:

J.F. Wickins and J. Barry, 1996. The Effect of Previous Experience on the Motivation to Burrow in Early Benthic Phase Lobsters (Homarus gammarus (L.)). Marine and Freshwater Behaviour and Physiology, 28: 211-228