Navigation Links
New analysis confirms sharks are in trouble

Sharks are in big trouble on the Great Barrier Reef and worldwide, according to an Australian-based team who have developed a world-first way to measure rates of decline in shark populations.

"There is mounting evidence of widespread, substantial, and ongoing declines in the abundance of shark populations worldwide, coincident with marked rises in global shark catches in the last half-century," say Mizue Hisano, Professor Sean Connolly and Dr William Robbins from the ARC Centre of Excellence for Coral Reef Studies and James Cook University.

"Overfishing of sharks is now recognized as a major global conservation concern, with increasing numbers of shark species added to the International Union for the Conservation of Nature's list of threatened species," they say in the latest issue of the international science journal PLos ONE.

"Evaluating population trends for sharks is complicated," explains Professor Connolly. "The simplest approach of looking at trends in fisheries catches doesn't work well for sharks. First, many countries with coral reefs don't keep reliable records of catches or fishing effort. Second, around 75 per cent of the world shark catch consists of illegal and unreported finning. Third, sharks may be caught, discarded, and not reported when fishers are targeting other species."

"An alternative is to take estimates of shark growth, birth, and mortality rates, and use these to calculate population growth rates. Estimates of growth and birth rates are easy to get, but it is very hard to get good estimates of mortality in sharks and other large animals," he says.

To deal with this problem, the team developed several alternative models, which combined birth rates and growth rates for sharks with a variety of different methods for estimating mortality. They then used state-of-the art statistical methods to combine the uncertainty associated with each of these methods and arrive at a more robust long-term population prediction for two GBR shark species -- the grey reef shark and the whitetip reef shark.

As a further check on their results, the researchers used their population projections to see how well their models could explain differences in shark abundances on fished and unfished reefs, based on how long the unfished reefs had been protected.

The team found that results obtained by all methods of assessing shark populations were in close agreement that sharks are declining rapidly due to fishing.

"Our different approaches all painted a surprisingly consistent picture of the current state of population decline, but also of the potential recovery of these species if they are adequately protected," says Mizue Hisano, the study's lead author.

For the Great Barrier Reef shark populations, the close agreement between the different methods appears to justify management actions to substantially reduce the fishing mortality of reef sharks.

"More broadly, we believe that our study demonstrates that this approach may be applied to a broad range of exploited species for which direct estimates of mortality are ambiguous or lacking, leading to improved estimates of population growth."


Contact: Sean Connolly
ARC Centre of Excellence in Coral Reef Studies

Related biology news :

1. Human Microbiome Project awards funds for technology development, data analysis and ethical research
2. MIT analysis shows how cap-and-trade plans can cut greenhouse emissions
3. Microarray analysis improves prenatal diagnosis
4. Powerful online tool for protein analysis provided pro bono by Stanford geneticist
5. US science education organization updates analysis
6. Execretion analysis aids primate social studies
7. Analysis of fresh strawberries reveals consumer preferences
8. Boehringer Ingelheim uses Genomatix Next Generation Sequencing data analysis systems
9. JCVI program trains USDA scientists on eukaryotic genome analysis
10. CRG buys Genomatix Next Generation Sequencing analysis solution
11. MCTP bought Genomatix NextGen Sequencing analysis stations
Post Your Comments:
(Date:6/22/2016)... -- On Monday, the Department of Homeland Security (DHS) ... for the Biometric Exit Program. The Request for Information ... explains that CBP intends to add biometrics to confirm ... States , in order to deter visa overstays, ... Logo - ...
(Date:6/16/2016)... , June 16, 2016 ... is expected to reach USD 1.83 billion by ... View Research, Inc. Technological proliferation and increasing demand ... are expected to drive the market growth. ... The development of advanced multimodal techniques ...
(Date:6/9/2016)... , June 9, 2016 ... deploy Teleste,s video security solution to ensure the safety of ... during the major tournament Teleste, an ... systems and services, announced today that its video security solution ... to back up public safety across the country. The ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... June 23, 2016 , ... Mosio, a leader in ... Trials Patient Recruitment and Retention Tips.” Partnering with experienced clinical research professionals, Mosio ... practical tips, tools, and strategies for clinical researchers. , “The landscape of how ...
(Date:6/23/2016)... 23, 2016 /PRNewswire/ - FACIT has announced the ... biotechnology company, Propellon Therapeutics Inc. ("Propellon" or ... of a portfolio of first-in-class WDR5 inhibitors for ... as WDR5 represent an exciting class of therapies, ... medicine for cancer patients. Substantial advances have been ...
(Date:6/23/2016)... MA (PRWEB) , ... June 23, 2016 , ... ... Peel Plate® YM (Yeast and Mold) microbial test has received AOAC Research Institute ... platform of microbial tests introduced last year,” stated Bob Salter, Vice President of ...
(Date:6/23/2016)... 2016   EpiBiome , a precision microbiome engineering ... debt financing from Silicon Valley Bank (SVB). The financing ... advance its drug development efforts, as well as purchase ... "SVB has been an incredible strategic partner to us ... bank would provide," said Dr. Aeron Tynes Hammack ...
Breaking Biology Technology: