Food consumption and energy expenditure of free ranging southern elephant seals

Elephant seals use a suite of physiological and behavioural mechanisms to maximise the time they can be submerged. Of these hypo-metabolism is one of the most important, so this study quantified maximum O2 consumptions relative to dove depth and swim speed.From the abstract of the referenced paper:Heart rate, swimming speed, and diving behaviour were recorded simultaneously for an adult female southern elephant seal during her postbreeding period at sea with a Wildlife Computers heart-rate time depth recorder and a velocity time depth recorder. The errors associated with data storage versus real-time data collection of these data were analysed and indicated that for events of short duration (i.e., less than 10 min or 20 sampling intervals) serious biases occur. A simple model for estimating oxygen consumption based on the estimated oxygen stores of the seal and the assumption that most, if not all, dives were aerobic produced a mean diving metabolic rate of 3.64 mL O2 kg-1, which is only 47% of the field metabolic rate estimated from allometric models. Mechanisms for reducing oxygen consumption while diving include cardiac adjustments, indicated by reductions in heart rate on all dives, and the maintenance of swimming speed at near the minimum cost of transport for most of the submerged time. Heart rate during diving was below the resting heart rate while ashore in all dives, and there was a negative relationship between the duration of a dive and the mean heart rate during that dive for dives longer than 13 min. Mean heart rates declined from 40 beats min-1 for dives of 13 min to 14 beats min-1 for dives of 37 min. Mean swimming speed per dive was 2.1 m s-1, but this also varied with dive duration. There were slight but significant increases in mean swimming speeds with increasing dive depth and duration. Both ascent and descent speeds were also higher on longer dives.Data were collected on Time Depth Recorders (TDRs), and stored in hexadecimal format. Hexadecimal files can be read using 'Instrument Helper', a free download from Wildlife Computers (see the provided URL).Data for this project is the same data that was collected for ASAC projects 769 and 589 (ASAC_769 and ASAC_589).

搜集汇总

背景与挑战

背景概述

该数据集研究了南象海豹在自由活动期间的摄食和能量消耗，通过记录心率、游泳速度和潜水行为，量化了潜水时的氧气消耗和低代谢机制。数据收集于1996年至1997年，覆盖南大洋区域，使用时间深度记录器存储，并公开提供以支持海洋哺乳动物生理生态研究。