Video-surveillance system for remote long-term in situ observations: recording diel cavity use and behaviour of wild European lobsters (Homarus gammarus)

Long-term studies of subtidal marine animals in the wild are a demanding enterprise. Traditionally, data collection has been limited to direct observations during SCUBA diving. In the past decade, video technology has improved rapidly and behavioural monitoring of marine organisms has successfully been conducted by using modern video-recording equipment. Here, we describe a video-monitoring system that employs video motion detection (VMD) and describe its use with the European lobster (Homarus gammarus). There is a shortage of detailed information on lobster behaviour in the wild, with virtually no published data on the fine-scale behaviour of the European lobster under natural conditions. This dearth of information reflects the difficulties in observing behaviour in nocturnal marine animals. Here, we explore whether a remote video-surveillance system is suitable for long-term monitoring of European lobsters inhabiting an artificial cavity in a natural habitat. From the video recordings, we were able to register diel cavity use and categorise behavioural elements such as resting, feeding, burrowing and substrate moving, self-cleaning, burrow occupancy and interactions among individuals. We propose that this novel system will contribute to more efficient data sampling of lobsters and facilitate non-invasive, long-term behavioural studies of other marine and freshwater animals.