Abstract:
Tethering prey is often used to help determine the impact of predators in aquatic communities. In this study, a novel photographic tethering device was used to make digital recordings of predation events on juveniles of the spiny lobster, Jasus edwardsii. Predation of lobsters was significantly higher during the day (76%) than at night (33.4%). This was consistent with a SCUBA survey that found greater numbers of diurnal predators than nocturnal predators at the study site. However, the abundance of predators was not consistent with the number of predation events for individual species as recorded by the photographic tethering device. The snapper, Pagrus auratus, was the most abundant species at the study site (45% of all diurnally active fishes), but was only responsible for 12% of predation events during the day. In contrast, wrasse species were responsible for the greatest number of predation events during the day (60%), yet made up only a small proportion of the diurnal fish population (25%). The results of this study indicate the importance of determining the identity of potential predators, through the use of a photographic tethering device, for increasing the value of results generated from tethering experiments.