Activity patterns of wild European lobster Homarus gammarus in coastal marine reserves: implications for future reserve design
Journal article, Peer reviewed
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European lobster Homarus gammarus in Norway has been in decline over the last 30 to 40 yr, and the species is currently red listed according to International Union for Conservation of Nature criteria. In 2006, experimental lobster reserves were established in the coastal Skagerrak, southern Norway, allowing for studies in the absence of disturbance by fishing gear. We present behavioural data from individual lobsters (n = 10) within 2 of the reserves. These data were obtained from data storage tags which logged in situ temperature and depth of specific individuals for up to 1 yr. To the best of our knowledge, these are the first direct measurements of depth obtained from freely behaving lobsters. Net movement exhibited by recaptured lobsters, measured as the distance between global positioning system positions recorded at the site of capture and recapture ranged from 15 to 580 m. Lobsters used habitats within a depth range of 1 to 57 m, and experienced sea temperatures ranging from 2°C during late winter (February to March) to 18°C during late summer (August to September). Lobster activity levels declined from September, reaching a minimum during February and March. From April, activity levels resumed. Seasonal variation in activity was correlated to water temperature (r2 = 0.55). Lobsters were more active during nighttime than during daytime, and there was a tendency for lobsters to reside in more shallow water during nighttime versus daytime. The present study suggests that future reserves for European lobster should be designed to include deeper habitat (30 to 50 m) in areas where such habitat exists when the management objective is long-term protection.