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Convergent foraging tactics of marine predators with different feeding strategies across heterogeneous ocean environments

Convergent foraging tactics of marine predators with different feeding strategies across heterogeneous ocean environments
Convergent foraging tactics of marine predators with different feeding strategies across heterogeneous ocean environments
Advances in satellite tracking and archival technologies now allow marine animal movements and behavior to be recorded at much finer temporal scales, providing a more detailed ecological understanding that can potentially be applicable to conservation and management strategies. Pelagic sharks are commercially exploited worldwide with current concerns that populations are declining, however, how pelagic sharks use exploited environments remains enigmatic for most species. Here we analyzed high-resolution dive depth profiles of two pelagic shark species with contrasting feeding strategies to investigate movement patterns in relation to environmental heterogeneity. Seven macropredatory blue (Prionace glauca) and six plankton-feeding basking (Cetorhinus maximus) sharks were tagged with pop-off satellite-linked archival tags in the North Atlantic Ocean to examine habitat use and investigate the function of dives. We grouped dives of both species into five major categories based on the two-dimensional dive profile shape. Each dive-shape class presented similar frequency and characteristics among the two species with U- and V-shaped dives predominating. We tested the spatial occurrence of different U- and V-shape dive parameters in response to environmental field gradients and found that mean depth and mean depth range decreased with increasing levels of primary productivity (chlorophyll “a”), whereas ascent velocities displayed a positive correlation. The results suggest that a planktivore and a macropredator responded behaviourally in similar ways to environmental heterogeneity. This indicates fine-scale dive profiles of shark species with different feeding strategies can be used to identify key marine habitats, such as foraging areas where sharks aggregate and which may represent target areas for conservation.
2296-7745
Queiroz, Nuno
f36209dc-ab54-40b0-8d3c-08a73ba298ef
Vila-Pouca, Catarina
c92040a0-e058-4db1-ad77-5284e5000966
Couto, Ana
880c3c6a-dead-4045-945a-c80e767bcc1f
Southall, Emily J.
0aa881e6-3e99-424f-bd6b-9720c1ab3c21
Mucientes, Gonzalo
b9e3388a-9fab-4982-8a7b-a5deb05c26b6
Humphries, Nicolas E.
9246d06a-396a-4c05-9721-dc340e75a4d0
Sims, David W.
7234b444-25e2-4bd5-8348-a1c142d0cf81
Queiroz, Nuno
f36209dc-ab54-40b0-8d3c-08a73ba298ef
Vila-Pouca, Catarina
c92040a0-e058-4db1-ad77-5284e5000966
Couto, Ana
880c3c6a-dead-4045-945a-c80e767bcc1f
Southall, Emily J.
0aa881e6-3e99-424f-bd6b-9720c1ab3c21
Mucientes, Gonzalo
b9e3388a-9fab-4982-8a7b-a5deb05c26b6
Humphries, Nicolas E.
9246d06a-396a-4c05-9721-dc340e75a4d0
Sims, David W.
7234b444-25e2-4bd5-8348-a1c142d0cf81

Queiroz, Nuno, Vila-Pouca, Catarina, Couto, Ana, Southall, Emily J., Mucientes, Gonzalo, Humphries, Nicolas E. and Sims, David W. (2017) Convergent foraging tactics of marine predators with different feeding strategies across heterogeneous ocean environments. Frontiers in Marine Science, 4, [00239]. (doi:10.3389/fmars.2017.00239).

Record type: Article

Abstract

Advances in satellite tracking and archival technologies now allow marine animal movements and behavior to be recorded at much finer temporal scales, providing a more detailed ecological understanding that can potentially be applicable to conservation and management strategies. Pelagic sharks are commercially exploited worldwide with current concerns that populations are declining, however, how pelagic sharks use exploited environments remains enigmatic for most species. Here we analyzed high-resolution dive depth profiles of two pelagic shark species with contrasting feeding strategies to investigate movement patterns in relation to environmental heterogeneity. Seven macropredatory blue (Prionace glauca) and six plankton-feeding basking (Cetorhinus maximus) sharks were tagged with pop-off satellite-linked archival tags in the North Atlantic Ocean to examine habitat use and investigate the function of dives. We grouped dives of both species into five major categories based on the two-dimensional dive profile shape. Each dive-shape class presented similar frequency and characteristics among the two species with U- and V-shaped dives predominating. We tested the spatial occurrence of different U- and V-shape dive parameters in response to environmental field gradients and found that mean depth and mean depth range decreased with increasing levels of primary productivity (chlorophyll “a”), whereas ascent velocities displayed a positive correlation. The results suggest that a planktivore and a macropredator responded behaviourally in similar ways to environmental heterogeneity. This indicates fine-scale dive profiles of shark species with different feeding strategies can be used to identify key marine habitats, such as foraging areas where sharks aggregate and which may represent target areas for conservation.

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Accepted/In Press date: 14 July 2017
e-pub ahead of print date: 2 August 2017

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Local EPrints ID: 413569
URI: http://eprints.soton.ac.uk/id/eprint/413569
ISSN: 2296-7745
PURE UUID: 8755082f-41a1-4804-aa60-10af9a8356ee

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Date deposited: 29 Aug 2017 16:30
Last modified: 27 Apr 2022 04:24

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Contributors

Author: Nuno Queiroz
Author: Catarina Vila-Pouca
Author: Ana Couto
Author: Emily J. Southall
Author: Gonzalo Mucientes
Author: Nicolas E. Humphries
Author: David W. Sims

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