Individual and Population Benefits of Marine Reserves for Reef Sharks

Dwyer, Ross G.; Krueck, Nils C.; Udyawer, Vinay; Heupel, Michelle R.; Chapman, Demian D.; Whitney, Nicholas M.; Garla, Ricardo C.; Simpfendorfer, Colin A.

doi:10.1016/j.cub.2019.12.005

Cited by 87 publications

(73 citation statements)

References 60 publications

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“…Furthermore, the variable periods of time over which these techniques are typically applied [3-6 months for satellite tags (Jaine et al, 2014;Braun et al, 2015), up to 10 years for internally implanted acoustic tags (Kessel et al, 2017), and potentially ongoing for photo-identification (Couturier et al, 2014)] provide insight into the conservation needs of this species over a range of temporal scales. Collectively, these spatiotemporal data can be used to develop scientifically informed management and conservation strategies for the species [e.g., Marine Protected Areas (MPAs); Germanov and Marshall, 2014;Peel et al, 2019b;Dwyer et al, 2020], and guide future research and monitoring efforts at both local scales (i.e., at aggregation sites and within populations), and more broadly throughout the range of M. alfredi.…”

Section: Introductionmentioning

confidence: 99%

Regional Movements of Reef Manta Rays (Mobula alfredi) in Seychelles Waters

et al. 2020

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The decline in numbers of reef manta rays (Mobula alfredi) throughout their range has highlighted the need for improved information on their spatial ecology in order to design effective conservation strategies for vulnerable populations. To understand their patterns of movement in Seychelles, we used three techniques-archival pop-up satellite tags, acoustic tags, and photo-identification-and focussed on the aggregation at D'Arros Island and St. Joseph Atoll within the Amirantes Group. M. alfredi were photographed within six of the seven Island Groups of Seychelles, with 64% of individuals being resighted at least once between July 2006 and December 2019 over timeframes of 1-3,462 days (9.5 years; median = 1,018 days). Only three individuals from D'Arros Island were resighted at a second aggregation site located more than 200 km away at St. François Atoll during photo-identification surveys. Satellite-tracked M. alfredi (n = 5 tracks; maximum 180 days) remained within the boundary of the Seychelles Exclusive Economic Zone, where they spent the majority of their time (87%) in the upper 50 m of the water column in close proximity to the Amirantes Bank. The inclusion of acoustic tagging data in the models of estimated satellite-track paths significantly reduced the errors associated with the geolocation positions derived from archived light level data. The insights gained into the patterns of horizontal and vertical movements of M. alfredi using this multi-technique approach highlight the significance of D'Arros Island and St. Joseph Atoll, and the wider Amirantes Group, to M. alfredi in Seychelles, and will benefit future conservation efforts for this species within Seychelles and the broader Western Indian Ocean.

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Section: Introductionmentioning

confidence: 99%

Regional Movements of Reef Manta Rays (Mobula alfredi) in Seychelles Waters

et al. 2020

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“…Marine protected areas (MPAs) are increasingly established around the world to protect biodiversity, but the degree to which they can help conserve mobile species remains contentious. Highly mobile and widely ranging species pose a considerable challenge for spatial management as protection across ranges of hundreds to thousands of kilometres is often impractical, while protecting too small an area or failing to protect key habitats may be ineffectual (see Dunn et al, 2019;Dwyer et al, 2020). To assess the effectiveness of spatial management or habitat protection, it is necessary to have a good understanding of residency, habitat use and movement scale (Cooke, 2008).…”

Section: Introductionmentioning

confidence: 99%

Satellite Tagging and Photographic Identification Reveal Connectivity Between Two UNESCO World Heritage Areas for Reef Manta Rays

Armstrong

McGregor

et al. 2020

Front. Mar. Sci.

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“…Optimal protection was reached at lower numbers of protected reefs when more suitable reefs were protected instead of poorly suitable ones. The demographic effect of protecting less suitable habitat in our simulations was a decreased expected longevity, which has already been recognized as a pervasive problem in shark conservation (Dwyer et al., 2019, 2020). Despite the capacity of high‐quality habitats to offset reduction of life expectancy and its variability, gains were marginal when compared with the number of breeding years lost to fishing, even for the most reef‐associated species.…”

Section: Discussionmentioning

confidence: 80%

Estimating marine protected area network benefits for reef sharks

Martín

Espinoza

Heupel

et al. 2020

Journal of Applied Ecology

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1. Animal movement has direct applications in spatial management and conservation planning, yet it is rarely taken into account for the design of natural protected areas. For instance, reef shark species are thought to benefit from marine protected area networks, even though their movement behaviour remains poorly characterized. Poor understanding of species' movements implies that the benefits of MPA networks for species' populations are still widely unknown. 2. To understand the consequences of movement behaviour for protection, we modelled movements of three reef shark species' (Carcharhinus albimarginatus, C. amblyrhynchos and C. leucas) with distinct levels of reef association using real passive-acoustic telemetry data. The model simulates if individuals are protected or unprotected by their movements in a system of reef patches in a network of MPAs. Model parameters that control individuals' movements were estimated from acoustic telemetry data. To estimate benefits for species we monitored longevity and time spent in protected habitats across all scenarios of reef protection, fishing intensity (11 values for each) and protection of high or low suitability reefs (a reef-dependent factor that attracts sharks to reside in it) for populations of 1,000 individuals per species. 3. The time individuals spent in protected reefs increased linearly with protection until it levelled off after 50%-80% of reefs protected (78% C. amblyrhynchos, 72% C. albimarginatus and 52% C. leucas, at 100% protection). Individuals' life span decreased exponentially with fishing intensity. Reef protection only mildly counteracted life span lost to fishing. Protecting highly suitable reefs increased time spent in protected reefs, optimal protection was reached at a lower number of reefs protected, and life expectancy was higher with protection of highly suitable reefs. 4. Synthesis and applications. Our framework can be applied to many studies using passive-acoustic telemetry to track animal movements. Protected area networks benefit species highly attached to protected sites. To increase benefits of marine protected area networks for all species (with low and high degrees of reef attachment) we need to understand the use of reef-adjacent areas, dispersal routes and characterize reef suitability for multiple species.

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Individual and Population Benefits of Marine Reserves for Reef Sharks

Cited by 87 publications

References 60 publications

Regional Movements of Reef Manta Rays (Mobula alfredi) in Seychelles Waters

Regional Movements of Reef Manta Rays (Mobula alfredi) in Seychelles Waters

Satellite Tagging and Photographic Identification Reveal Connectivity Between Two UNESCO World Heritage Areas for Reef Manta Rays

Estimating marine protected area network benefits for reef sharks

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