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Intraspecific differences in movement,dive behavior and vertical habitat preferences of a key marine apex predator

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Stehfest, KM and Patterson, TA and Barnett, A and Semmens, JM (2014) Intraspecific differences in movement,dive behavior and vertical habitat preferences of a key marine apex predator. Intraspecific differences in movement, dive behavior and vertical habitat preferences of a kjey marine apex predator, 495. pp. 249-262. ISSN 0171-8630

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Abstract

Understanding the patterns of large-scale movements of highly mobile marine
predators is essential to understanding the impacts of anthropogenic pressures on the animals and
the ecosystems they frequent. The broadnose sevengill shark Notorynchus cepedianus is one of
the most important apex predators in temperate coastal areas around the world, yet little is known
of its seasonal large-scale movements. Five male and five female sevengill sharks were equipped
with pop-up satellite archival tags (PSATs) in a coastal embayment in southern Tasmania, that collected
depth and temperature data during winter, when the animals leave the coastal embayment,
resulting in a dataset covering a total of 818 d. Animal tracks indicated that males moved northwards
into warmer waters, whereas females remained in southern waters. Three of the females
stayed in the Tasmanian coastal areas while the other two left, with one of them moving into
deeper waters of up to 360 m depth at the southern edge of the Tasmanian shelf before returning
to the Tasmanian coast. These sex-specific differences in large-scale movement could potentially
lead to the differential exploitation of the sexes when the sharks leave the protected areas where
they were tagged. Both males and females switched between diel vertical migration and reverse
diel vertical migration over the course of their tracks and displayed oscillatory vertical movements,
probably linked to foraging. These vertical movements persisted throughout the tracks,
suggesting that sevengill sharks foraged continuously during their migration rather than switching
between transiting and foraging modes.

Item Type: Article
Keywords: Broadnose sevengill shark · Notorynchus cepedianus · Pop-up satellite archival tag · Biotelemetry · Wavelet analysis · Sex-specific · Hexanchiformes
Journal or Publication Title: Intraspecific differences in movement, dive behavior and vertical habitat preferences of a kjey marine apex predator
Page Range: pp. 249-262
ISSN: 0171-8630
Identification Number - DOI: 10.3354/meps10563
Additional Information:

Copyright 2014 Inter-Research

Date Deposited: 20 Jan 2014 01:09
Last Modified: 18 Nov 2014 04:57
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