Marine & Environmental Sciences Faculty Articles

Vertical Movements of Shortfin Mako Sharks Isurus oxyrinchus in the Western North Atlantic Ocean are Strongly Influenced by Temperature

Document Type

Article

Publication Date

4-7-2016

Publication Title

Marine Ecology Progress Series

Keywords

Habitat use, Satellite tracking, Dive behavior, Telemetry

ISSN

0171-8630

Volume

87

First Page

163

Last Page

175

Abstract

Although shortfin mako sharks Isurus oxyrinchus are regularly encountered in pelagic fisheries, limited information is available on their vertical distribution and is primarily restricted to cooler areas of their geographic range. We investigated the vertical movements of mako sharks across differing temperature regimes within the western North Atlantic by tagging 8 individuals with pop-up satellite archival tags off the northeastern United States and the Yucatan Peninsula, Mexico. Depth and temperature records across 587 d showed vertical movements strongly associated with ocean temperature. Temperatures <15°C created a lower depth limit to most diving behaviors, and shifts in depths used coincided with changes in the thermal properties of the vertical habitat. In the warmest water columns, sharks spent 36% of the daytime at depths >150 m compared to only 1% in the coldest water columns. The sharks showed diel diving behavior, with deeper dives occurring primarily during the daytime (maximum depth: 866 m). Overall, sharks experienced temperatures between 5.2 and 31.1°C. When the opportunity was available, sharks spent considerable time in waters ranging from 22 to 27°C, indicating underestimation of the previously reported upper limit of the mako sharks’ preferred temperature. The preference for higher temperatures does not support endothermy as an adaption for niche expansion in mako sharks. The strong influence of thermal habitat on movement behavior suggests potentially strong impacts of rising ocean temperatures on the ecology of this highly migratory top predator.

Comments

©2016 Inter-Research.

Additional Comments

Florida Sea Grant Program grant #: R/LR-B-73; National Marine Fisheries Service grant #: NA97FE0363

ORCID ID

0000-0002-3753-8950

ResearcherID

G-4080-2013

DOI

10.3354/meps11646

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