The Patagonian slope is the region where Subantarctic waters and bathymetry give raise to physical and ecological processes that support a rich biodiversity and a large-scale industrial fisheries. Unique among the species that depend on this region is the deep diving southern elephant seal, Mirounga leonina. We report here on changes in the foraging behavior of a female seal explained by the combined effect of a cold and high salinity water mass and a decrease in surface chlorophyll-a concentration. Behavioral and oceanographic data from about 5000 profiles of temperature, conductivity, pressure, light and prey encounters were collected within an area ranging 59.5–61°W and 46–47.5°S, at depths of 300–700 m, on the Patagonian slope, during November–December 2018. A decrease in temperature (0.15 °C) and an increase in salinity (0.03) was found below the mixed layer, during December. Light data revealed a significant increase of irradiance in December (almost reaching the ocean bottom) associated with a decrease of chlorophyll-a in the upper levels. Concomitantly, the seal had a different diving behavior in December, foraging near the surface at night and close to the bottom during daylight hours. Also, the seal doubled the prey capture attempts in December compared to November. This study reveals the importance of ocean physical properties on seal's diving and foraging behavior, and how this changes, although small, can impact on seals diet and body composition during their post-breeding trips.

巴塔哥尼亚斜坡是亚南极​​水域和水深测量产生支持丰富生物多样性和大规模工业渔业的物理和生态过程的区域。在依赖该地区的物种中独一无二的是深潜的南象海豹Mirounga leonina. 我们在此报告雌性海豹觅食行为的变化，原因是寒冷和高盐度的水团以及表面叶绿素-a 浓度降低的综合影响。在巴塔哥尼亚斜坡上 59.5-61°W 和 46-47.5°S 的区域内收集了大约 5000 个温度、电导率、压力、光和猎物遭遇剖面的行为和海洋学数据，深度为 300-700 m， 2018 年 11 月至 12 月期间。在 12 月期间，在混合层下方发现温度下降 (0.15 °C) 和盐度增加 (0.03)。光数据显示 12 月（几乎到达海底）的辐照度显着增加，与上层叶绿素 a 的减少有关。与此同时，海豹在 12 月有不同的潜水行为，夜间在水面附近觅食，白天在水底附近觅食。此外，与 11 月相比，海豹在 12 月捕获猎物的次数增加了一倍。这项研究揭示了海洋物理特性对海豹潜水和觅食行为的重要性，以及这种变化虽然很小，但如何影响海豹繁殖后旅行期间的饮食和身体成分。