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Large marine parks can save sharks from overfishing threat

Date:
January 23, 2020
Source:
University of Queensland
Summary:
'No-take' marine reserves -- where fishing is banned -- can reverse the decline in the world's coral reef shark populations caused by overfishing, according to a new study. But researchers found that existing marine reserves need to be much larger to be effective against overfishing.
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'No-take' marine reserves -- where fishing is banned -- can reverse the decline in the world's coral reef shark populations caused by overfishing, according to an Australian study.

But University of Queensland, James Cook University (JCU) and University of Tasmania researchers found that existing marine reserves need to be much larger to be effective against overfishing.

UQ's Dr Ross Dwyer said the study estimated that no-take reserves that extend between 10 and 50 kilometres along coral reefs can achieve significant improvements in shark populations.

"Existing protected areas on coral reefs would need to be enforced as strict no-take reserves and be up to five times larger to effectively conserve reef sharks," Dr Dwyer said.

"Those in the Atlantic where reef sharks are generally less abundant would need to be on average 2.6 times larger than those in the Indian and Pacific Oceans."

Species such as grey reef sharks have experienced severe population declines across parts of their distribution, largely due to their low fecundity, late age at sexual maturity, and high susceptibility to fishing pressure.

They are listed as Near Threatened in the International Union for Conservation of Nature's (IUCN) Red List of Threatened Species.

The researchers combined large volumes of tracking data on five species of sharks found on coral reefs in the Indian, Pacific and Atlantic oceans, with video survey data from 36 countries.

"This allowed us to predict the conservation benefits no-take reserves of different sizes could generate," Dr Dwyer said.

JCU Professor Colin Simpfendorfer from James Cook University said shark populations were in trouble in most parts of the world.

"Finding ways to rebuild their populations is critical to ensuring our oceans remain healthy," Professor Simpfendorfer said.

"This project is providing options for managers of coral reefs to address declines in shark populations which scientists know have occurred in many areas."

Dr Nils Krueck from the University of Tasmania said researchers now have the ability to estimate conservation and fishery impacts of marine reserves much more precisely.

"Our results show that marine parks for reef sharks need to be large. But if reserves extend along 15 kilometres of coral reef, then fishing mortality can be reduced by fifty per cent," Dr Krueck said.

The study, funded by the Shark Conservation Fund, is published in the journal Current Biology.


Story Source:

Materials provided by University of Queensland. Note: Content may be edited for style and length.


Journal Reference:

  1. Ross G. Dwyer, Nils C. Krueck, Vinay Udyawer, Michelle R. Heupel, Demian Chapman, Harold L. Pratt, Ricardo Garla, Colin A. Simpfendorfer. Individual and Population Benefits of Marine Reserves for Reef Sharks. Current Biology, 2020; DOI: 10.1016/j.cub.2019.12.005

Cite This Page:

University of Queensland. "Large marine parks can save sharks from overfishing threat." ScienceDaily. ScienceDaily, 23 January 2020. <www.sciencedaily.com/releases/2020/01/200123152509.htm>.
University of Queensland. (2020, January 23). Large marine parks can save sharks from overfishing threat. ScienceDaily. Retrieved June 13, 2024 from www.sciencedaily.com/releases/2020/01/200123152509.htm
University of Queensland. "Large marine parks can save sharks from overfishing threat." ScienceDaily. www.sciencedaily.com/releases/2020/01/200123152509.htm (accessed June 13, 2024).

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