New Zealand sea lion movement and dive data - Campbell Island/Motu Ihupuku

We hypothesised that New Zealand sea lions from Campbell Island/Motu Ihupuku of various sex and age classes would utilise the water column differently due to differing physiological constraints and therefore have different accessibility to prey resources. We tested whether sea lion diving behaviour varied in relation to (i) age and sex class, (ii) time of day and (iii) water depth. We also hypothesized that the proportion of benthic/pelagic diving, and consequently risk of fisheries interaction, would vary in relation to age and sex. Satellite telemetry tags were deployed on 25 NZSL from a range of age/sex classes recording dive depth, duration and location. Adult females and juveniles used inshore, benthic habitats, while sub-adult males also utilised benthic habitats, they predominantly used pelagic habitat at greater distances from the island. Adult females and juveniles exhibited shorter dives than the same age/sex classes at the Auckland Islands, suggesting a lower dive effort for these age/sex classes at Campbell Island.

本研究假设，来自坎贝尔岛/莫图伊胡普库（Campbell Island/Motu Ihupuku）的不同性别、不同年龄阶层的新西兰海狮，会因生理限制条件存在差异，对水体层的利用方式有所不同，进而获取猎物资源的可及性也存在区别。本研究验证了海狮的潜水行为是否与以下因素相关：(i) 年龄与性别阶层；(ii) 一日中的时段；(iii) 水深。本研究同时假设，底栖（benthic）/大洋性（pelagic）潜水的占比，以及由此产生的渔业交互风险，会随年龄与性别不同而发生变化。研究人员为覆盖不同年龄/性别阶层的25只新西兰海狮（New Zealand sea lions, NZSL）部署了卫星遥测标签，记录其潜水深度、时长与位置信息。成年雌性海狮与幼龄海狮会利用近岸底栖生境；亚成年雄性海狮虽也会利用底栖生境，但主要在距离该岛屿更远的海域使用大洋性生境。成年雌性海狮与幼龄海狮的潜水时长较奥克兰群岛同年龄/性别阶层的海狮更短，这表明坎贝尔岛的该类年龄与性别阶层的海狮，其潜水投入更低。