科学家检查了40名少年白鲨的胃中内容物,并惊讶地看到他们花了多长时间沿着海床狩猎。
“The stereotype of a shark’s dorsal fin above the surface as it hunts is probably not a very accurate picture,” said University of Sydney Ph.D. candidate Richard Grainger. He’s the lead author of a study on white shark feeding habits published on Sunday in the journalFrontiers in Marine Science.
鲨鱼的饮食主要由澳大利亚鲑鱼(32.2%)等中水鱼组成,但像唯一的底部鱼类占胃含量的17.4%。其余的包括猎物,例如礁鱼和黄貂鱼。混合物中也有一些身份不明的鱼。
The researchers matched up their data with previous research on the subject. “This indicates the sharks must spend a good portion of their time foraging just above the seabed,”said Grainger.
The juvenile sharks covered by the research had mostly been snacking on small bites. “The hunting of bigger prey, including other sharks and marine mammals such as dolphin, is not likely to happen until the sharks reach about 2.2 meters in length,” said Grainger.
The study pointed to larger sharks choosing higher fat diets, a finding that makes sense considering their energy needs.
The deceased sharks were caught in nets deployed by theNew South Wales Shark Meshing Program,旨在保护游泳者免受海洋掠食者的侵害,但也会导致某些动物的死亡。科学家在论文中指出:“没有为这项研究而被专门杀死动物。”
The findings could help with species management and conservation decisions. “Understanding the nutritional goals of these cryptic predators and how these relate to migration patterns will give insights into what drives human-shark conflict and how we can best protect this species,” said study co-author Gabriel Machovsky-Capuska.