A common bottlenose dolphin (Tursiops truncatus) prey handling technique for marine catfish (Ariidae) in the northern Gulf of Mexico PLOS ONE

Few accounts describe predator-prey interactions between common bottlenose dolphins (Tursiops truncatus Montagu 1821) and marine catfish (Ariopsis felis Linnaeus 1766, Bagre marinus Mitchill 1815). Over the course of 50,167 sightings of bottlenose dolphin groups in Mississippi Sound and along the Florida coast of the Gulf of Mexico, severed catfish heads were found floating and exhibiting movements at the surface in close proximity to 13 dolphin groups that demonstrated feeding behavior. These observations prompted a multi-disciplinary approach to study the predator-prey relationship between bottlenose dolphins and marine catfish. A review was conducted of bottlenose dolphin visual survey data and dorsal fin photographs from sightings where severed catfish heads were observed. Recovered severed catfish heads were preserved and studied, whole marine catfish were collected and examined, and stranding network pathology reports were reviewed for references to injuries related to fish spines. Photographic identification analysis confirms eight dolphins associated with severed catfish heads were present in three such sightings across an approximately 350 km expanse of coast between the Mississippi Sound and Saint Joseph Bay, FL. An examination of the severed catfish heads indicated interaction with dolphins, and fresh-caught whole hardhead catfish (A. felis) were examined to estimate the presumed total length of the catfish before decapitation. Thirty-eight instances of significant trauma or death in dolphins attributed to ingesting whole marine catfish were documented in stranding records collected from the southeastern United States of America. Bottlenose dolphins typically adhere to a ram-feeding strategy for prey capture followed by whole prey ingestion; however, marine catfish skull morphology may pose a consumption hazard due to rigid spines that can puncture and migrate through soft tissue, prompting a prey handling technique for certain dolphins, facilitating consumption of the posterior portion of the fish without the head.

鲜有研究报道普通宽吻海豚（Tursiops truncatus Montagu, 1821）与海鲶（Ariopsis felis Linnaeus, 1766、Bagre marinus Mitchill, 1815）之间的捕食者-猎物互作关系。研究团队在密西西比湾及墨西哥湾佛罗里达沿岸开展的50167次宽吻海豚群目击调查中，于13个表现出摄食行为的海豚群周边海面，发现漂浮且仍保有活动能力的断裂鲶鱼头。上述观测结果推动了一项多学科研究项目，以探究宽吻海豚与海鲶之间的捕食者-猎物互作关系。研究人员对目击到断裂鲶鱼头的相关宽吻海豚目视调查数据及背鳍照片进行了系统性梳理与分析；对采集得到的断裂鲶鱼头进行了保存与形态学研究，同时收集完整海鲶个体开展检测，并梳理搁浅监测网络的病理报告，以查找与鱼棘相关的损伤记录。照片识别分析确认，在密西西比湾至佛罗里达州圣约瑟夫湾约350公里的海岸范围内，3次相关目击事件中共记录到8头与断裂鲶鱼头相关的宽吻海豚个体。对断裂鲶鱼头的检测显示其存在与海豚互动的痕迹；同时研究人员对新鲜捕获的完整棘海鲶（A. felis）进行检测，以估算该鲶鱼被斩首前的预估总长度。在美国东南部收集的海豚搁浅记录中，共记录到38起因吞食完整海鲶导致海豚遭受严重创伤乃至死亡的案例。宽吻海豚通常采用冲刺摄食（ram-feeding）策略捕获猎物并整体吞食；但海鲶的头骨形态存在摄食风险——其坚硬的棘刺可刺穿海豚软组织并在体内迁移，因此部分海豚演化出了特定的猎物处理技巧，即移除鱼头后仅食用鱼体后部组织。