Discovering behaviours in captive Port Jackson sharks (Heterodontus portusjacksoni) using accelerometers

Uncovering how animals utilise their time in the wild is vital to understanding their ecology. Continuous observation in a marine environment is not feasible, but telemetry devices provide an opportunity for fine-scale analysis of movement and behaviour. We used accelerometers to investigate activity patterns and behaviours of the Port Jackson shark (Heterodontus portusjacksoni) with the aim of building a model from captive sharks that can be applied to wild populations. We developed techniques to identify behaviours from two types of accelerometers - high and low resolution. To validate the accelerometer data, we identified shark behaviours from multi-angle, high definition video that was time-matched to both types of accelerometer data. The low-resolution accelerometer (Vemco V13AP) was used to identify diel patterns and migratory restlessness in captive sharks. Wild shark diel patterns and presence data were used as a comparative measure to validate findings. The high-resolution accelerometer (Cefas G6a+) tested the application of a classification tree method in classifying four behaviours: resting, swimming, vertical swimming against the wall of the enclosure and chewing on prey. Through evaluating the ability of two types of accelerometers to identify captive shark behaviour, we are validating methods for long-term (low resolution - looking for trends) and short-term (high resolution- detailed behaviours) observation of wild shark populations.