Fine-scale whisker growth measurements can reveal temporal foraging patterns from stable isotope signatures

Marine Ecology Progress Series

Megan Connolly Sadou¹  Richard Condit¹  Colleen Reichmuth¹  Daniel P. Costa¹  Roxanne S. Beltran¹  Sarah H. Peterson¹ 

关键词: Vibrissae;    Whisker;    Asymptotic growth rate;    Stable isotope;    Seal;   

DOI  :  10.3354/meps11176

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Stable isotope analysis of slow-growing, metabolically inert tissues is a common method for investigating foraging ecology in migratory animals, as direct observations of feeding are often not possible. Using tissue growth dynamics to interpret foraging timelines can maximize the utility of foraging data; however, applying inappropriate growth models is problematic, and high-resolution growth measurements are seldom made. We used photogrammetry to repeatedly measure the length of whiskers in 93 follicles over 670 d in a trained, captive northern elephant seal Mirounga angustirostris. We developed and optimized a follicle-specific growth model to describe the 18000 whisker length measurements. Whiskers from the captive seal exhibited asymptotic growth that was described by the von Bertalanffy growth function. Applying the growth model to serially sampled whiskers from 4 free-ranging adult female northern elephant seals resulted in alignment of peaks in δ¹⁵N along the length of whiskers with the breeding haul-out period, when seals are not feeding. Our study provides a high-resolution whisker growth model and is the first to use whisker growth dynamics to improve temporal interpretation of isotopic ratios.

【 授权许可】

Unknown