Sex and Size Influence the Spatiotemporal Distribution of White Sharks, With Implications for Interactions With Fisheries and Spatial Management in the Southwest Indian Ocean
Rattachement africain : Afrique du Sud, au, gb. Niveau de preuve : code pays fourni par la source.
Le résumé fourni par la source
Human activities in the oceans increase the extinction risk of marine megafauna. Interventions require an understanding of movement patterns and the spatiotemporal overlap with threats. We analysed the movement patterns of 33 white sharks (Carcharodon carcharias) satellite-tagged in South Africa between 2012 and 2014 to investigate the influence of size, sex and season on movement patterns and the spatial and temporal overlap with longline and gillnet fisheries and marine protected areas (MPAs). We used a hidden Markov model to identify ‘resident’ and ‘transient’ movement states and investigate the effect of covariates on the transition probabilities between states. A model with sex, total length and season had the most support. Tagged sharks were more likely to be in a resident state near the coast and a transient state away from the coast, while the probability of finding a shark in the transient state increased with size. White sharks moved across vast areas of the southwest Indian Ocean, emphasising the need for a regional management plan. White sharks overlapped with longline and gillnet fisheries within 25% of South Africa’s Exclusive Economic Zone and spent 15% of their time exposed to these fisheries during the study period. The demersal shark longline fishery had the highest relative spatial and temporal overlap, followed by the pelagic longline fishery and the KwaZulu-Natal (KZN) shark nets and drumlines. However, the KZN shark nets and drumlines reported the highest white shark catches, emphasising the need to combine shark movement and fishing effort with reliable catch records to assess risks to shark populations accurately. White shark exposure to shark nets and drumlines, by movement state, sex and maturity status, corresponded with the catch composition of the fishery, providing support for a meaningful exposure risk estimate. White sharks spent significantly more time in MPAs than expected by chance, likely due to increased prey abundance or less disturbance, suggesting that MPAs can benefit large, mobile marine megafauna. Conservation of white sharks in Southern Africa can be improved by implementing non-lethal solutions to beach safety, increasing the observer coverage in fisheries, and continued monitoring of movement patterns and existing and emerging threats.
Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.
Le contrôle bibliographique ouvert
DOI retrouvé dans Crossref DOI retrouvé ; titre concordant.
- Titre Crossref
- Sex and Size Influence the Spatiotemporal Distribution of White Sharks, With Implications for Interactions With Fisheries and Spatial Management in the Southwest Indian Ocean
- Date Crossref
- 07/04/2022
- Éditeur
- Frontiers Media SA
- Type
- journal-article
Ce recoupement confirme des métadonnées liées au DOI. Il ne confirme ni la méthode ni les conclusions de l’étude, et il ne compte pas comme une seconde source scientifique indépendante.
Où se fait cette recherche
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South African National Parks Afrique du Sud (code pays fourni par la source)Organisme public
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University of Cape Town Department of Biological Sciences University of Cape Town, Afrique du Sud (code pays fourni par la source)Université ou école supérieure
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Institute for Communities and Wildlife in Africa Afrique du Sud (code pays fourni par la source)Université ou école supérieure
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South African Institute for Aquatic Biodiversity Grahamstown, Afrique du Sud (code pays fourni par la source)Structure de recherche
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Nelson Mandela University Institute for Coastal and Marine Research Gqeberha, Afrique du Sud (code pays fourni par la source)Université ou école supérieure
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South African Association for Marine Biological Research Afrique du Sud (code pays fourni par la source)Institution
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Department of Agriculture Western Cape Government, Afrique du Sud (code pays fourni par la source)Organisme public
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Rhodes University Department of Ichthyology and Fisheries Science Grahamstown, Afrique du Sud (code pays fourni par la source)Université ou école supérieure
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Dyer Island Conservation Trust Afrique du Sud (code pays fourni par la source)Institution
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The University of Western Australia pays non établi dans la noticeUniversité ou école supérieure
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University of St Andrews pays non établi dans la noticeUniversité ou école supérieure
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Cape Research Centre Afrique du Sud (pays nommé en fin d’affiliation)Structure de recherche
South African National Parks (Afrique du Sud), Department of Biological Sciences — University of Cape Town (University of Cape Town, Afrique du Sud) et Institute for Communities and Wildlife in Africa (Afrique du Sud), avec 9 autres affiliations. Pays d’affiliation : Afrique du Sud.
Une affiliation ne permet pas de déduire la nationalité d’un auteur.