Food Consumption and Foraging Success of Free-ranging Southern Elephant SealsEntry ID: ASAC_769
Abstract: 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:
The ability of air-breathing marine predators to forage successfully depends on their ability to ... remain submerged. This is in turn related to their total O2 stores and the rate at which these stores are used up while submerged. Body size was positively related to dive duration in a sample of 34 adult female southern elephant seals from Macquarie Island. However, there was no relationship between body size and dive depth. This indicates that smaller seals, with smaller total O2 stores, make shorter dives than larger individuals but operate at similar depths, resulting in less time being spent at depth. Nine adult female elephant seals were also equipped with velocity time depth recorders. In eight of these seals, a plot of swimming speed against dive duration revealed a cloud of points with a clear upper boundary. This boundary could be described using regression analysis and gave a significant negative relationship in most cases. These results indicate that metabolic rate varies with activity levels, as indicated by swimming speed, and that there are quantifiable limits to the distance that a seal can travel on a dive of a given swimming speed. However, the seals rarely dive to these physiological limits, and the majority of their dives are well within their aerobic capacity. Elephant seals therefore appear to dive in a way that ensures that they have a reserve of O2 available.
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 url given below).
Data for this project is the same data that was collected for ASAC projects 857 and 589 (ASAC_857 and ASAC_589).
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Start Date: 1994-09-01Stop Date: 1996-03-31
Access Constraints The data are publicly available for download from the url given below.
Use Constraints This data set conforms to the PICCCBY Attribution License
Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=ASAC_769 when using these data.
Also, please contact the investigator when using these data.
Data Set Progress
Distribution Media: HTTP
Distribution Size: 9266 kb
Distribution Format: hexadecimal
Role: TECHNICAL CONTACT
Role: DIF AUTHOR
Phone: +61 3 6226 2645
Fax: +61 3 6226 2745
Email: mark.hindell at utas.edu.au
ANTARCTIC WILDLIFE R'SRCH UNIT Department of Zoology University of Tasmania GPO BOX 252-05
Province or State: Tasmania
Postal Code: 7001
Hindell, M.A., Lea, M., Morrice, M. and McMahon, C.R. 2001. Metabolic limitations on dive duration and swimming speed in the southern elephant seal, Mirounga leonina. Physiological and Biochemical Zoology 73: 790-798.
Creation and Review Dates
DIF Creation Date: 2000-08-07
Last DIF Revision Date: 2010-12-21