Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Overfishing of sharks is harming coral reefs

20.09.2013
A team of scientists from Canada and Australia has discovered that a decline in shark populations is detrimental to coral reefs.

“Where shark numbers are reduced due to commercial fishing, there is also a decrease in the herbivorous fishes which play a key role in promoting reef health,” said Jonathan Ruppert, a recent University of Toronto PhD graduate. Ruppert was part of a team engaged in long-term monitoring of reefs off Australia’s northwest coast.

Team leader Mark Meekan, of the Australian Institute of Marine Science (AIMS), said that the results might, at first glance, seem strange.

“However our analysis suggests that where shark numbers are reduced, we see a fundamental change in the structure of food chains on reefs,” Meekan said.

“We saw increasing numbers of mid-level predators – such as snappers – and a reduction in the number of herbivores such as parrotfishes,” said Meekan. “The parrotfishes are very important to coral reef health because they eat the algae that would otherwise overwhelm young corals on reefs recovering from natural disturbances.”

According to Ruppert, the study comes at an opportune time – coral reefs are facing a number of pressures both from direct human activity, such as over-fishing, as well as from climate change.

The reefs studied are about 300 kilometres off the coast of northwest Australia where Indonesian fishers target sharks – a practice stretching back several centuries and which continues under an Australian-Indonesian memorandum of understanding.

“The reefs provided us with a unique opportunity to isolate the impact of over-fishing of sharks on reef resilience, and assess that impact in the broader context of climate change pressures threatening coral reefs,” said Ruppert. “Shark fishing appears to have quite dramatic effects on coral reef ecosystems.

“Given that sharks are in decline on reefs worldwide, largely due to the shark fin trade, this information may prove integral to restoration and conservation efforts.”

Tracking studies show that, in many cases, individual reef sharks are closely attached to certain coral reefs. This means that even relatively small marine-protected areas could be effective in protecting the top-level predators and allowing coral reefs to more fully recover from coral bleaching or large cyclones which are increasing in frequency due to the warming of the oceans as a result of climate change.

The study will appear in the September 28 issue of journal PLOS One.

Lead author Ruppert completed his PhD at the University of Toronto and was also based at AIMS for part of his research. He is currently a post-doctoral research associate at York University. Other team members included Marie-Josée Fortin of U of T’s Department of Ecology and Evolutionary Biology, Michael Travers of AIM and Luke Smith, the principal environmental scientist at Woodside Energy.

The research was funded by the Natural Sciences and Engineering Research Council of Canada and Woodside Energy of Perth, Australia.

For more information, contact:

U of T Media Relations
416-978-2100
media.relations@utoronto.ca

U of T Media Relations | EurekAlert!
Further information:
http://www.utoronto.ca

Further reports about: Overfishing coral reef food chain reef ecosystem

More articles from Ecology, The Environment and Conservation:

nachricht Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München

nachricht Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Salmonella as a tumour medication

HZI researchers developed a bacterial strain that can be used in cancer therapy

Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Microfluidics probe 'cholesterol' of the oil industry

23.10.2017 | Life Sciences

Gamma rays will reach beyond the limits of light

23.10.2017 | Physics and Astronomy

The end of pneumonia? New vaccine offers hope

23.10.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>