Marine protected area helps shark populations recover from fishing

Publication specs

Title: Evidence for rapid recovery of shark populations within a coral reef marine protected area

Authors: Conrad Speed, Mike Cappo, Mark Meekan

Journal: Biological Conservation

Year: 2018

The diminishing number of sharks around the world is no longer a topic of interest just for scientists and fisheries managers. Many people who rely on these animals as resources – whether as food or for ecotourism operations – are becoming aware of the menacing situation facing certain shark populations due to overfishing, shark finning, habitat loss, and climate change. Until now, there has been little evidence that marine protected areas benefit sharks in coral reef habitats. Thanks to Paul G. Allen Philanthropies, the first results coming from our sampling provide insight into the recovery of grey reef sharks and apex predator species like the tiger shark and lemon shark at a remote atoll in the Indian ocean.

Ashmore reef is situated 350km northwest of Australia’s mainland, and has been an enforced no-take marine protected area (MPA) since 2008. Although the official establishment of the Ashmore Reef National Nature Reserve was in 1983, only occasional monitoring of the area was happening until 2008 when a government vessel became stationed there 300 days out of the year. Prior to the inception of the MPA, there was legal and illegal targeted shark fishing. In 2004, researchers from the Australian Institute of Marine Science (AIMS) conducted baited remoted underwater video surveys (BRUVs) at Ashmore Reef. The AIMS research team then returned in 2016 to repeat the study as part of our global survey of sharks and rays on coral reefs around the world.

This provided the ideal set-up to study Ashmore Reef shark populations before and after full protection. Findings show:

 

The relative average number of grey reef sharks (measured as the maximum number of individuals per camera drop; MaxN) increased from about 0.16 individuals per hour in 2004 to approximately 0.74 individuals per hour in 2016.

 

 

The proportion of reef sharks (grey reef sharks, blacktip reef sharks, and silvertip sharks) in the assemblage increased from 28.6% in 2004 to 57.6% in 2016.28.6%  57.6%
 

 

The proportion of apex species (tiger sharks, lemon sharks, scalloped hammerheads, and fossil sharks) in the assemblage increased from 7.1% in 2004 to 11.9% in 2016.
 
 
 

 


 7.1%  11.9%
 

 

This study is not only our project’s first publication, it is also one of the first of its kind in a coral reef ecosystem to highlight that enforcement in a marine protected area aided shark population recovery and at a rate much faster than previously predicted by demographic models.

Global FinPrint

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