Navigation Links
New analysis confirms sharks are in trouble
Date:9/29/2011

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
Sean.Connolly@jcu.edu.au
61-074-781-4242
ARC Centre of Excellence in Coral Reef Studies
Source:Eurekalert

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:
*Name:
*Comment:
*Email:
(Date:4/5/2017)... YORK , April 5, 2017 Today ... is announcing that the server component of the HYPR ... known for providing the end-to-end security architecture that empowers ... HYPR has already secured over 15 million ... makers including manufacturers of connected home product suites and ...
(Date:3/30/2017)... March 30, 2017  On April 6-7, 2017, Sequencing.com ... Genome hackathon at Microsoft,s headquarters in ... will focus on developing health and wellness apps that ... Hack the Genome is the first hackathon for ... world,s largest companies in the genomics, tech and health ...
(Date:3/28/2017)... The report "Video Surveillance Market ... Storage Devices), Software (Video Analytics, VMS), and Service (VSaaS, ... to 2022", published by MarketsandMarkets, the market was valued ... to reach USD 75.64 Billion by 2022, at a ... year considered for the study is 2016 and the ...
Breaking Biology News(10 mins):
(Date:4/27/2017)... ... April 27, 2017 , ... ... electronic informed consent (eConsent) solution that simplifies research studies, accelerates study startup, and ... of Quorum, Q Consent™ is the first and only IRB-integrated eConsent solution ...
(Date:4/27/2017)... ... April 27, 2017 , ... ... a name change to Fluence Analytics. , Fluence Analytics provides proprietary ... and biopharmaceutical manufacturing processes and R&D applications. The company’s patented technologies improve ...
(Date:4/27/2017)... 27, 2017  Kinexum, a distinguished resource for research, ... the appointment of Thomas C. Seoh as ... M.D., Kinexum founder, who becomes Executive Chairman and will ... clients. Thomas Seoh commented, "I ... mission and lead the firm,s remarkable team of life ...
(Date:4/26/2017)... ... 2017 , ... LABS, Inc. (LABS) announced in December 2016 that two ... Nucleic Acid Testing (NAT) for ZIKV; and Enzyme Immunoassays (EIAs) specific for IgM and ... for blood donors under an Investigational New Drug (IND) study protocol. , Now, ...
Breaking Biology Technology: