Does spatial distribution of lemon sharks (Negaprion brevirostris) in the wild correlate with temperament in semi-captivity?
Supervisors: Tristan Guttridge, Samuel Gruber (Bimini Biological Field Station, Bahamas)
Whether through predator-prey dynamics, interactions with conspecifics, or reactions to its environment, temperament (or behaviour) has a significant effect on the ways in which an individual interacts with its surroundings, and must be taken into consideration for effective management and conservation of a species. The field of animal behaviour is well established in the literature, and there are numerous accepted assays for multiple axes of behaviour in animals across a variety of taxa. In fish, however, behavioural research has been largely confined to small species such as zebrafish, three-spined stickleback, and guppies, which are easily kept and manipulated in the laboratory. Behavioural studies in elasmobranchs have received little scientific attention, in part due to the difficulty of maintaining individuals in captivity, their conservation status, and often their large size. This study examines behavioural assay results from one of the first novel environment assays of a large-bodied elasmobranch, the lemon shark (Negaprion brevirostris), and compares these results to spatial distribution in the wild, using acoustic telemetry techniques. We used passive acoustic telemetry to determine home range SURs at 95 % of total detections. Data from active acoustic telemetry was used to calculate home range estimates at 50 % and 90 % using minimum convex polygon (MCP) and fixed kernel estimators. We found a significant positive correlation between activity score (novel open environment assay for exploration) and the total number of SURs on which a shark was detected. Exploratory behaviour was correlated to number of home range SURs (95 % of total detections). Analysis of active tracking results showed a significant correlation between activity score and mean distance to shore of tracking points, with a greater distance to shore for sharks with high activity scores. There was no significant correlation between shark size (PCL) and activity score, total number of detected SURs, or number of home range SURs. Our sample size was small (n = 7 after filtering), and warrants repeated trials with a larger sample, however our mortality matched that of previous experiments. Through our results, we conclude that the behaviour of lemon sharks during novel environment tests for exploration are significantly correlated to their spatial use of habitat and their behaviour in the wild.