New Evidence Finds Marine Protected Areas Rapidly Increase Shark Populations After Years Of Overfishing

Photo: Global Fin Print

Shark populations have been dwindling world-wide now for a number of years to do over-fishing, habitat destruction and pollution. The diminishing number of sharks worldwide is starting to become a topic of interest for more than just scientists, conversationalist and fishery managers.

People worldwide are bringing their attention to the importance of sharks to our oceans as we move away from the “Jaws Culture” and towards one of conservation and appreciation. The leading method to improve shark and other marine populations is to create or expand Marine Protected Areas (MPAs).

Due to the relatively new practice of establishing Marine Protected Areas, there is limited evidence of the effectiveness the MPA has on shark populations rebounding but a new study will help conservationist argue for their importance.

In a study published in Science Direct, evidence has been found that shows rapid recovery of shark population on coral reefs within a Marine Protected Area.  The study was performed on Ashmore Reef In Western Australia by using baited underwater remote video surveys in 2004 prior to the enforcement of the MPA. Then again in 2016, eight years after the strict enforcement of the MPA, they surveyed the same area.

What researchers found was that apex species, such as tiger sharks, increased from 7.1% to 11.9% of total community population, while reef sharks increased from 28.6% to 57.6%. At the same time, researchers found that the proportional abundance of lower trophic level species decreased from 64.3% to 30.5% as sharks were back to controlling the ecosystem, creating a better balance.

Total shark counts at Ashmore Reef in 2004 were very similar to count of the Scott Reefs currently, where targeted fishing for sharks still occurs. In 2016, total shark count had recovered to resemble the counts of those on the Rowley Shoals, a reef system that has been a strictly enforced MPA for over 25 years.

The abundance in sharks and community structure coincide directly with the enforcement of the MPA is very encouraging to researchers and conservationists. This research will help in debating for the creation of more MPAs or making current MPAs even larger.

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