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Life-history, exploitation and extinction risk of the data-poor Baraka's whipray (Maculabatis ambigua) in small-scale tropical fisheries

Lookup NU author(s): Dr Andrew Temple, Professor Selina Stead, Dr Ellen Barrowclift-Mahon, Professor Per Berggren

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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Abstract

© 2020 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of The Fisheries Society of the British Isles.The Baraka's whipray (Maculabatis ambigua) is a major constituent of small-scale fisheries catch in the south-western Indian Ocean. Despite this, little is known of its life-history or exploitation status. We provide the first estimates of crucial life-history parameters and the maximum intrinsic population growth rate rmax, using specimens collected from small-scale fisheries landings in Kenya, Zanzibar and Madagascar (with northern Madagascar representing a range extension for this species). We assess the relative risk of overexploitation by combining rmax with estimates of total Z, fishing F, and natural M mortality, and an estimate of the exploitation ratio E. The data indicate that Baraka's whipray is a medium-sized, fast-growing, early maturing species, with a relatively long lifespan. This results in a high rmax relative to many other elasmobranchs, which when combined with estimates of F suggests that the species is not at imminent risk of extinction. Yet, estimates of exploitation ratio E indicate likely overfishing for the species, with full recruitment to the fishery being post-maturation and exploitation occurring across a broad range of age and size classes. Thus, Baraka's whipray is unlikely to be biologically sustainable in the face of current fisheries pressures. This paper makes an important contribution to filling the gap in available data and is a step towards developing evidence-based fisheries management for this species. Further, it demonstrates a simple and widely applicable framework for assessment of data-poor elasmobranch exploitation status and extinction risk.


Publication metadata

Author(s): Temple AJ, Stead SM, Jiddawi N, Wambiji N, Dulvy NK, Barrowclift E, Berggren P

Publication type: Article

Publication status: Published

Journal: Journal of Fish Biology

Year: 2020

Volume: 97

Issue: 3

Pages: 708-719

Print publication date: 01/09/2020

Online publication date: 10/06/2020

Acceptance date: 08/06/2020

Date deposited: 20/07/2020

ISSN (print): 0022-1112

ISSN (electronic): 1095-8649

Publisher: Blackwell Publishing Ltd

URL: https://doi.org/10.1111/jfb.14425

DOI: 10.1111/jfb.14425


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