de la Vega Camille, Lebreton Benoit, Siebert Ursula, Guillou Gael, Das Krishna, Asmus Ragnhild, Asmus Harald
AlfredWegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Wattenmeerstation Sylt Hafenstr. 43, D-25992 List/ Sylt, Germany.
Littoral Environnement et Sociétés (LIENSs), CNRS-Université de la Rochelle, Bâtiment ILE 2, rue Olympe de Gouges 17 000 La Rochelle, France.
PLoS One. 2016 May 13;11(5):e0155727. doi: 10.1371/journal.pone.0155727. eCollection 2016.
The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight.
瓦登海在海洋哺乳动物的休息、哺育和觅食方面发挥着重要作用。港海豹是该区域数量最多的海洋哺乳动物物种。海豹对瓦登海食物资源的利用情况尚不清楚，此前的研究表明，该物种能够从其上岸休息处游出数公里远，到北海觅食。在本研究中，我们分析了在叙尔特岛发现的23只死亡港海豹触须的稳定同位素，以调查它们的饮食情况。将捕食者的碳和氮同位素组成与叙尔特-勒姆岛湾及北海不同潜在猎物的组成进行比较，以便研究饮食和觅食地点的季节性模式。同时，研究了叙尔特-勒姆岛湾潜在猎物的丰度和生物量的季节性变化，并将其与它们对海豹饮食的贡献进行比较。结果显示，海豹的饮食从春季的浮游食物来源转变为夏季以底栖生物为主的饮食，并且根据叙尔特-勒姆岛湾猎物可获得性的季节性变化，在秋季和冬季对北海资源的利用有所增加。
