The heterogeneous oceanographic conditions of continental shelf ecosystems result in a three-dimensionally patchy distribution of prey available to upper-trophic level predators. The association of bio-physical conditions with movement patterns of large marine predators has been demonstrated in diverse taxa. However, obtaining subsurface data that are spatio-temporally relevant to the decisions made by benthically-foraging species can be challenging. Between 2009 and 2015, grey seals were captured on Sable Island, Nova Scotia, Canada during summer and fall and instrumented with high-resolution archival GPS tags. These tags recorded location data as well as depth (m), temperature (°C), and light level measurements during dives, until animals returned to the haulout site to breed. Hidden Markov models were used to predict apparent foraging along movement tracks for 79 individuals (59 females, 20 males) every 3 h. In situ measurements were used to estimate chlorophyll-a concentration (mg m− 3) and temperature within the upper-water column (50 m) and temperature and depth at the bottom of dives. As chlorophyll-a could only be estimated from 10:00 to 14:00 AST for dive depths ≥50 m, we formulated two generalized linear mixed-effects models to test the association of predicted grey seal behavioural states with oceanographic conditions and phytoplankton biomass: the first representing conditions of the upper-water column likely to influence primary productivity, and a second model including environmental conditions encountered by grey seals at the bottom of dives, when seals were more likely to be foraging. Predicted grey seal behavioural states were associated with fine-scale chlorophyll-a concentrations and other environmental conditions they encountered across the continental shelf. In the Water Column Model, season had no influence on the probability of observing apparent foraging, but chlorophyll-a, upper-water column temperature, and sex did, with females having a greater probability of foraging than males. In the Bottom Conditions Model, again season had no influence on the probability of apparent foraging, but females were over twice as likely as males to be foraging. The results of this study highlight the value of in situ measurements of oceanographic properties that can be collected at high temporal resolution by animal-borne data loggers. These data provide insight into how inferred behavioural decisions made by large marine predators, such as the grey seal, may be influenced by fine-scale oceanographic conditions.

中文翻译：

---

大陆架海洋捕食者灰海豹 (Halichoerus grypus) 的觅食行为与原地、地下海洋条件有关

大陆架生态系统的异质海洋条件导致上层营养级捕食者可获得猎物的三维斑块分布。生物物理条件与大型海洋捕食者的运动模式的关联已在不同的分类群中得到证实。然而，获得与底栖觅食物种做出的决策时空相关的地下数据可能具有挑战性。2009 年至 2015 年间，在夏季和秋季期间，在加拿大新斯科舍省的黑貂岛捕获了灰海豹，并配备了高分辨率档案 GPS 标签。这些标签记录了潜水期间的位置数据以及深度 (m)、温度 (°C) 和光照水平测量值，直到动物返回拖运地点进行繁殖。隐马尔可夫模型用于每 3 小时预测 79 个人（59 名女性，20 名男性）沿运动轨迹的明显觅食。现场测量用于估计叶绿素-a 浓度 (mg m- 3) 和上层水柱 (50 m) 内的温度以及潜水底部的温度和深度。由于叶绿素-a 只能在 10:00 到 14:00 AST 估计潜水深度≥50 m，我们制定了两个广义线性混合效应模型来测试预测的灰海豹行为状态与海洋条件和浮游植物生物量的关联：第一个代表可能影响初级生产力的上层水柱条件，第二个模型包括灰海豹在潜水底部遇到的环境条件，此时海豹更有可能觅食。预测的灰海豹行为状态与它们在大陆架上遇到的精细叶绿素-a 浓度和其他环境条件有关。在水柱模型中，季节对观察到明显觅食的概率没有影响，但叶绿素-a、上层水柱温度和性别有影响，雌性比雄性具有更大的觅食概率。在底部条件模型中，季节再次对明显觅食的概率没有影响，但女性觅食的可能性是男性的两倍多。这项研究的结果突出了海洋特性的原位测量值，这些特性可以通过动物传播的数据记录器以高时间分辨率收集。这些数据提供了对大型海洋捕食者如何推断行为决策的洞察，