Post-capture survival of whale sharks released from purse seine nets: preliminary results from tagging experiment | Bycatch Management Information System (BMIS)

Year

2014

Species Groups

Sharks and Rays

Fishing Gear

Purse Seine

Mitigation Techniques

Safe handling & release

Management Categories

At-Vessel and Post-Release Mortality

Tagging Studies

Type

Report

Authors

Escalle, L.

Chavance, P.

Amande, J.M.

Filmalter, J. D.

Forget, F.

Gaertner, D.

Dagorn, L.

Merigot, B.

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Source URL

http://www.iotc.org/documents/post-capture-survival-whale-sharks-released-purse-seine-nets-preliminary-results-tagging

Citation

Escalle L, Chavance P, Amande JM, et al (2014) Post-capture survival of whale sharks released from purse seine nets: preliminary results from tagging experiment. IOTC, Yokohama, Kanagawa, Japan

Abstract

In the tropical Atlantic Ocean, whale sharks are at times encircled in tuna purse seine nets. While the apparent survival rates after encirclement have been assessed through scientific observer programs, the post-released survival has not yet been investigated. This study describes pop-up satellite tagging and release methods and provides preliminary results on the assessment of survival of whale sharks after release from purse seine nets. Five whale sharks were tagged in July 2014. Three tags popped-up on the programmed date (30 days) and thus these sharks are considered to have survived. One tag surfaced prematurely (after 21 days), complicating the interpretation of the fate of this animal, and one tag failed to report altogether. Obtaining accurate estimations of the post-release survival of whale shark encircled by purse seine nets will require the deployment of further tags on incidentally captured individuals.