Effects of near-bed current speeds on the distribution and behaviour of the lobster, Homarus gammarus (L.)

The distribution of the lobster, Homarus gammarus (L.) appears to be limited to areas of the sea bed with rocky outcrops. It seems likely that this limitation operates because lobsters need to be able to avoid currents created by tidal and wave action and that it is size selective. A series of experiments was made with lobsters in a flume tank, to observe the effects of a range of current speeds and substratum types on lobster behaviour. In addition, depth profiles of flow rates were made by Pitot tube measurements to estimate flow rates within the boundary layer immediately above the sea bed. Predictions of the influence of natural water currents on lobster behaviour have been made using available data on near-bed current speeds. The implications of these predictions to fisheries management and reef construction plans are discussed.