Yo-yo vertical movements suggest a foraging strategy for tiger sharks Galeocerdo cuvier

Marine Ecology Progress Series

Itsumi Nakamura¹  Carl G. Meyer¹  Yuuki Y. Watanabe¹  Katsufumi Sato¹  Yannis P. Papastamatiou¹ 

关键词: Tiger shark;    Marine top predator;    Swimming behavior;    Swim speed;    Stroke frequency;    Foraging;    Bio-logging;    Data logger;   

DOI  :  10.3354/meps08980

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Many pelagic fishes exhibit ‘yo-yo’ diving behavior, which may serve several possible functions, including energy conservation, prey searching and navigation. We deployed accelerometers and digital still cameras on 4 free-ranging tiger sharks Galeocerdo cuvier, to test whether their vertical movements are most consistent with energy conservation or prey searching. All sharks swam continuously, with frequent vertical movements through the water column at mean swimming speeds of 0.5 to 0.9 m s^–1. Tail-beating was continuous except for sporadic, powerless gliding during descents (from 0 to 18% of total descent time). At a given tailbeat frequency, swimming speeds were lower during ascent than descent (consistent with negative buoyancy). Burst swimming events, which might represent prey pursuits, were observed during all phases of vertical movements. Camera images showed a variety of potential prey and the possible capture of a unicornfish. Collectively, results suggest that yo-yo diving by tiger sharks is not primarily for energy conservation, but probably represents an effective search strategy for locating prey throughout the water column.

【 授权许可】

Unknown