A New Method to Quantify within Dive Foraging Behaviour in Marine Predators

摘要: Studies on diving behaviour classically divide a dive into three phases: the descent, bottom and ascent phases, with foraging assumed to occur during phase. The greater complexity of revealed through modern, high resolution data highlights need re-assess this approach consider larger number phases within individual dives. Two southern elephant seals (SES) were fitted head mounted Time Depth Recorder (TDR) an accelerometer from which prey capture attempts estimated. A Weddell seal was also TDR. TDRs for both species recorded depth once per second. We quantified using automated broken stick algorithm identifying optimal segments each dive. vertical sinuosity used infer two types behaviours, highly sinuous indicating "hunting" less "transiting". Using method alternated between "transit" modes average 6±2 7±0.02 behavioural SES, respectively. In 77% (identified acceleration data) occurred in ("hunting") as defined by our new approach. SES spent more time transit mode dive, hunting mostly Conversely phase but at shallower depths. Such differences probably reflect different tactics habitat use. For species, differs significantly previously proxy therefore provides accurate fine-scale description seals' behaviour.