Department of Research and Conservation, Georgia Aquarium, Atlanta, GA, 30313, USA.
Department of Animal Health, Georgia Aquarium, Atlanta, GA, 30313, USA.
Sci Rep. 2020 Nov 12;10(1):19753. doi: 10.1038/s41598-020-76858-w.
Ecotourism opportunities in the marine environment often rely heavily on provisioning to ensure the viewing of cryptic species by the public. However, intentional feeding of wildlife can impact numerous aspects of an animals' behavior and ecology. Southern stingrays (Hypanus americana) provisioned at Stingray City Sandbar (SCS) in Grand Cayman have altered diel activity patterns and decreased measures of health. This study looked at seasonal changes in stable isotope (SI) and fatty acid (FA) profiles of provisioned stingrays at SCS. Plasma δN was higher in male stingrays (11.86 ± 1.71‰) compared to females (10.70 ± 1.71‰). Lower values for δN in males and females were measured in October during low tourist season, suggesting stingrays may be forced to rely on native prey items to supplement the decreased amount of provisioned squid available during this time. Plasma FA profiles were significantly different between sexes and across sampling time points, with FAs 22:6n3, 16:0, 20:5n3, 18:1n3C, 18:0 and 18:1n9T contributing to dissimilarity scores between groups. Dietary FAs primarily contributed to differences between males and females lending further evidence to differences in foraging patterns at SCS, likely due to intraspecific competition. Further, canonical analysis of principal coordinates (CAP) analysis of FA profiles suggest similar diets during peak tourist season and differences in diet between males and females during the low season. This study demonstrates alterations in feeding ecology in stingrays at SCS which is of critical importance for effective management of the SCS aggregation.
海洋环境中的生态旅游机会通常严重依赖供应来确保公众能够观赏隐匿物种。然而，野生动物的故意投喂会影响动物行为和生态的许多方面。在大开曼岛的 Stingray City Sandbar（SCS），为南方黄貂鱼（Hypanus americana）提供食物供应已改变了它们的昼夜活动模式，并降低了健康指标。本研究调查了 SCS 中投喂黄貂鱼的稳定同位素（SI）和脂肪酸（FA）谱的季节性变化。雄性黄貂鱼的血浆 δN 高于雌性（11.86±1.71‰）。在旅游淡季 10 月，雌雄两性的 δN 值较低，这表明黄貂鱼可能被迫依赖本地猎物来补充这段时间内供应减少的鱿鱼量。雄性和雌性之间以及不同采样时间点的血浆 FA 谱存在显著差异，FA 22:6n3、16:0、20:5n3、18:1n3C、18:0 和 18:1n9T 对群体间的不相似性评分有贡献。饮食 FA 主要导致雄性和雌性之间的差异，这进一步证明了 SCS 觅食模式的差异，可能是由于种内竞争造成的。此外，FA 谱的典型对应分析（CAP）分析表明，在旅游旺季期间饮食相似，而在淡季期间雄性和雌性之间的饮食存在差异。本研究表明，SCS 黄貂鱼的摄食生态发生了变化，这对 SCS 聚集区的有效管理至关重要。
