Out-of-water transportation effects on behaviour in newly released juvenile Atlantic lobsters Homarus gammarus

Abstract

After a release of juvenile Altantic lobsters ( Homarus gammarus) in Norway in August 1988, more than 10% were eaten by fishes within an hour. The fish were attracted to the release site by lobsters which repeatedly swam towards the surface. Most of the lobsters however remained immobile on the sea bottom for several minutes. The cause of these behavioural differences may be the initial transportation conditions. The lobsters had been packed tightly in wet wooden shavings and newspapers in cooled boxes. Laboratory experiments showed that a change in pressure and water loss gave an increase both in the frequency of rushes and in duration of immobility. Change in lighting conditions had little effect. Decrease in manipulations on the lobsters gave increased walking frequency. The paper suggests that in-water transportation or appropriate acclimation conditions at the release site are vital to avoid releasing stressed lobsters.