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Reproductive schedules in southern bluefin tuna: are current assumptions appropriate?

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posted on 2023-05-19, 09:04 authored by Evans, K, Patterson, TA, Reid, H, Harley, SJ
Southern bluefin tuna (SBT) appear to comprise a single stock that is assumed to be both mixed across its distribution and having reproductive adults that are obligate, annual spawners. The putative annual migration cycle of mature SBT consists of dispersed foraging at temperate latitudes with migration to a single spawning ground in the tropical eastern Indian Ocean. Spawning migrations have been assumed to target two peaks in spawning activity; one in September-October and a second in February-March. SBT of sizes comparable to that of individuals observed on the spawning ground were satellite tagged in the Tasman Sea region (2003–2008) and demonstrated both migrations to the spawning grounds and residency in the Tasman Sea region throughout the whole year. All individuals undertaking apparent spawning migrations timed their movements to coincide with the second recognised spawning peak or even later. These observations suggest that SBT may demonstrate substantial flexibility in the scheduling of reproductive events and may even not spawn annually as currently assumed. Further, the population on the spawning grounds may be temporally structured in association with foraging regions. These findings provide new perspectives on bluefin population and spatial dynamics and warrant further investigation and consideration of reproductive schedules in this species.

History

Publication title

PLoS One

Volume

7

Issue

4

Article number

e34550

Number

e34550

Pagination

1-7

ISSN

1932-6203

Department/School

Institute for Marine and Antarctic Studies

Publisher

Public Library of Science

Place of publication

United States

Rights statement

Copyright 2012 Evans et al. Licensed under Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Repository Status

  • Open

Socio-economic Objectives

Wild caught tuna

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