ELECTROMAGNETIC TELEMETRY OF LOBSTER (HOMARUS-GAMMARUS (L.)) MOVEMENTS AND ACTIVITY - PRELIMINARY-RESULTS

Individual European lobsters were tracked on an artificial reef using an electromagnetic telemetry system, which detected movements between reef units and also recorded body movements (pitching and rolling) ind icated by a tilt switch incorporated into the transmitting tag. Severa l environmental variables were recorded simultaneously by the telemetr y system, which was self-contained on the seabed. To date, 26 lobsters (14 female, 12 male) have been tagged, up to seven have been monitore d simultaneously and four individuals have been tracked for over 6 mon ths. Movements between units of the artificial reef (over open seabed away from shelter) were predominantly nocturnal, although daytime move ments occurred during periods of low light levels associated with incr eased turbidity resulting from wave action. A marked decline in the nu mber of inter-reef movements from late summer to winter was most close ly related to decreasing water temperature. Activity indicated by the tilt switch was greater at night for most lobsters, but there were mod erate levels of activity during the day. As with inter-reef movements, activity declined as winter progressed and in addition the diel patte rn diminished.