Reef accessibility impairs the protection of sharks

Type Article
Date 2018-03
Language English
Author(s) Juhel Jean-Baptiste1, 2, 3, Vigliola Laurent2, Mouillot David3, 4, Kulbicki Michel5, Letessier Tom B.6, 7, 8, Meeuwig Jessica J.7, 8, Wantiez LaurentORCID1
Affiliation(s) 1 : Univ Nouvelle Caledonie, Noumea, New Caledonia, New Caledonia.
2 : IRD, Lab Excellence LABEX Corail, UMR ENTROPIE, Noumea, New Caledonia, France.
3 : Univ Montpellier, UMR MARBEC 9190, Montpellier 5, France.
4 : James Cook Univ, Ctr Excellence Coral Reef Studies, Australian Res Council, Townsville, Qld, Australia.
5 : Univ Perpignan, Lab Excellence LABEX Corail, UMR ENTROPIE, IRD, Perpignan, France.
6 : Zool Soc London, Inst Zool, Regents Pk, London, England.
7 : Univ Western Australia, Sch Biol Sci, Crawley, WA, Australia.
8 : Univ Western Australia, Oceans Inst, Crawley, WA, Australia.
Source Journal Of Applied Ecology (0021-8901) (Wiley), 2018-03 , Vol. 55 , N. 2 , P. 673-683
DOI 10.1111/1365-2664.13007
WOS© Times Cited 34
Keyword(s) baited remote underwater video system, baseline, coral reef, Elasmobranch, human impact, human proximity, marine protected area, reef shark, underwater visual census

1. Reef sharks are declining world-wide under ever-increasing fishing pressure, with potential consequences on ecosystem functioning. Marine protected areas (MPAs) are currently one of the management tools used to counteract the pervasive impacts of fishing. However, MPAs in which reef sharks are abundant tend to be located in remote and underexploited areas, preventing a fair assessment of management effectiveness beyond remoteness from human activities. 2. Here, we determine the conditions under which MPAs can effectively protect sharks along a wide gradient of reef accessibility, from the vicinity of a regional capital towards remote areas, using 385 records from baited remote underwater video systems and 2,790 underwater visual censuses performed in areas open to fishing and inside 15 MPAs across New Caledonia (South-Western Pacific). 3. We show that even one of the world's oldest (43 years), largest (172 km(2)) and most restrictive (no-entry) MPA (Merlet reserve) on coral reefs has between 17.3% and 45.3% fewer shark species and between 37.2% and 79.8% fewer shark abundance than remote areas in a context where sharks are not historically exploited. 4. On coral reefs situated at less than 1 hr of travel time from humans, shark populations are so low in abundance (less than 0.05 individuals per 1,000 m(2)) that their functional roles are severely limited. 5. Synthesis and applications. Remote areas are the last sanctuaries for reef sharks, providing a new baseline from which to evaluate human impacts on the species. However, there is no equivalent close to human activities even in large, old and strongly restrictive marine protected areas. As such sharks deserve strong protection efforts. The large, no-entry marine protected areas, close to humans, offer limited benefits for reef shark populations, but provide more realistic conservation targets for managers of human-dominated reefs. The exclusion of human activities on a sufficiently large area is key to protect reef shark populations. However, this strategy remains difficult to apply in many countries critically depending on reef resources for food security or livelihood.

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