Shifting elasmobranch community assemblage at Cocos Island—an isolated marine protected area

  • Published source details White E.R., Myers M.C., Flemming J.M. & Baum J.K. (2015) Shifting elasmobranch community assemblage at Cocos Island—an isolated marine protected area. Conservation Biology, 29, 1186-1197.


This study is summarised as evidence for the following.

Action Category

Cease or prohibit all types of fishing in a marine protected area

Action Link
Marine Fish Conservation
  1. Cease or prohibit all types of fishing in a marine protected area

    A replicated study in 1993–2013 of 17 reef areas off Cocos Island, in the eastern Pacific Ocean, Costa Rica (White et al. 2015) found that over a period of 21 years, eight of twelve shark and ray species declined in abundance or presence inside a no-fishing marine protected area established for over 15 years, and poor enforcement may have contributed to the decline. Percentage declines in observed abundance in the period from 1993 to 2013 were recorded for six of twelve species (scalloped hammerhead Sphyrna lewini: 45%, whitetip reef shark Triaenodon obesus: 77%, marble ray Taeniura meyeni: 73%, eagle ray Aetobatus narinari: 34%, mobula ray Mobula spp.: 78%, manta ray Manta birostris: 89%) and declines in the likelihood of occurrence recorded for two (silky shark Carcharhinus falciformis: 91%, silvertip shark Carcharhinus albimarginatus: 87%). The likelihood of occurrence of four species increased between 1993 and 2013: tiger sharks Galeocerdo cuvier (79%/yr, Galapagos sharks Carcharhinus galapagensis (33%/yr), blacktip reef sharks Carcharhinus limbatus (9%/year) and whale sharks Rhincodon typus (5%/yr). In addition, the authors reported inadequate enforcement of fishing controls were likely to contribute to the declines. The Cocos Island National Park was designated in 1978, and extended in 1984 and 2001, covering 22.2 km around the island. Fishing is banned within the park but enforcement is poor and illegal shark fishing occurs. From 1993 to 2013 divers surveyed sharks and rays at 17 sites within the reserve by underwater visual census for one hour. Sites were between 10 and 40 m depth. Common species were recorded as count data and analysed as relative abundance while presence-absence data were recorded for rare species and analysed as odds of occurrence.

    (Summarised by: Natasha Taylor)

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