Navigation Links
Scientists provide first large-scale estimate of reef shark losses in the Pacific Ocean
Date:4/27/2012

HONOLULU April 25, 2012 -- Many shark populations have plummeted in the past three decades as a result of excessive harvesting for their fins, as an incidental catch of fisheries targeting other species, and in recreational fisheries. This is particularly true for oceanic species. However, until now, a lack of data prevented scientists from properly quantifying the status of Pacific reef sharks at a large geographic scale.

In a study published online April 27 in the journal Conservation Biology, an international team of marine scientists provide the first estimates of reef shark losses in the Pacific Ocean. Using underwater surveys conducted over the past decade across 46 U.S. Pacific islands and atolls, as part of NOAA's extensive Pacific Reef Assessment and Monitoring Program (www.pifsc.noaa.gov/cred/) the team compared reef shark numbers at reefs spanning from heavily impacted ones to those among the world's most pristine.

The numbers are sobering.

"We estimate that reef shark numbers have dropped substantially around populated islands, generally by more than 90 percent compared to those at the most untouched reefs", said Marc Nadon, lead author of the study and a scientist at the Joint Institute for Marine and Atmospheric Research (JIMAR) located at the University of Hawaii, as well as a PhD candidate with Dr. Jerry Ault at the University of Miami's Rosenstiel School of Marine & Atmospheric Science. "In short, people and sharks don't mix."

To obtain these estimates, Nadon and his colleagues used an innovative survey method, called 'towed-diver surveys,' which were designed specifically for the census of large, highly mobile reef fishes like sharks. The surveys involve paired SCUBA divers recording shark sightings while towed behind a small boat.

"Towed-diver surveys are key to our effort to quantify reef shark abundance," said Ivor Williams, head of the team responsible for these surveys. "Unlike other underwater census methods, which are typically at an insufficient spatial scale to properly count large, mobile species, these surveys allowed our scientists to quickly record shark numbers over large areas of reef."

The team crunched the numbers from over 1,600 towed-diver surveys, combining them with information on human population, habitat complexity, reef area, and satellite-derived data on sea surface temperature and oceanographic productivity.

The models showed the enormous detrimental effect that humans have on reef sharks.

"Around each of the heavily populated areas we surveyed in the main Hawaiian Islands, the Mariana Archipelago, and American Samoa - reef shark numbers were greatly depressed compared to reefs in the same regions that were simply further away from humans." Nadon said. "We estimate that less than 10% of the baseline numbers remain in these areas."

Like all fishes, reef sharks are influenced by their environment. "They like it warm, and they like it productive," said Julia Baum, Assistant Professor at the University of Victoria, Canada, referring to the increase in reef sharks the team found in areas with higher water temperatures and productivity. "Yet our study clearly shows that human influences now greatly outweigh natural ones."

"The pattern of very low reef shark numbers near inhabited islands was remarkably consistent, irrespective of ocean conditions or region," added Williams.

"Our findings underscore the importance of long-term monitoring across gradients of human impacts, biogeographic, and oceanic conditions, for understanding how humans are altering our oceans," concluded Rusty Brainard, head of the Coral Reef Ecosystem Division at NOAA's Pacific Islands Fisheries Science Center, which conducted the surveys.


'/>"/>
Contact: Barbra Gonzalez
barbgo@rsmas.miami.edu
305-421-4704
University of Miami Rosenstiel School of Marine & Atmospheric Science
Source:Eurekalert  

Related biology news :

1. Stanford and MIT scientists win Perl-UNC Neuroscience prize
2. Queens is UK leader for female scientists and engineers
3. Scientists uncover strong support for once-marginalized theory on Parkinsons disease
4. Scientists develop new technique that could improve heart attack prediction
5. Scientists advance field of research with publication of newly validated method for analyzing flavanols in cocoa
6. Scripps research scientists find anticonvulsant drug helps marijuana smokers kick the habit
7. Scientists have discovered genes that increase the risk of osteoporosis and fractures
8. Marine scientists urge government to reassess oil spill response
9. Scientists find Achilles heel in life-threatening malaria parasites
10. Scientists find that neurological changes can happen due to social status
11. Scientists discover switch in plants to create flowers
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Scientists provide first large-scale estimate of reef shark losses in the Pacific Ocean
(Date:11/15/2016)... , Nov 15, 2016 Research and ... Global Forecast to 2021" report to their offering. ... ... USD 16.18 Billion by 2021 from USD 6.21 Billion in 2016, ... Growth of the bioinformatics market is driven by the ...
(Date:6/22/2016)... 22, 2016  The American College of Medical Genetics and ... Magazine as one of the fastest-growing trade shows during ... the Bellagio in Las Vegas . ... of growth in each of the following categories: net square ... number of attendees. The 2015 ACMG Annual Meeting was ranked ...
(Date:6/20/2016)... 2016 Securus Technologies, a leading provider ... public safety, investigation, corrections and monitoring announced that ... has secured the final acceptance by all three ... Access Systems (MAS) installed. Furthermore, Securus will have ... installed by October, 2016. MAS distinguishes between legitimate ...
Breaking Biology News(10 mins):
(Date:12/8/2016)... ... December 08, 2016 , ... From wearable devices that can ... sports. On Thursday, December 15th a panel of entrepreneurs, innovators and a Philadelphia ... at a Smart Talk session. Smart Talk will run from 8:30 – 10:30 ...
(Date:12/8/2016)... , ... December 08, 2016 , ... ... to control cells — optogenetics — is key to exciting advances in the ... art, spatially patterned light projected via free-space optics stimulates small, transparent organisms and ...
(Date:12/8/2016)... ... December 08, 2016 , ... KBioBox llc announced today ... demand KbioBox developed a sophisticated “3 click” gene dditing off target analysis program ... new website, https://www.kbiobox.com/ and powered by the company’s proprietary BioEngine. ...
(Date:12/8/2016)... 8, 2016 Soligenix, Inc. (OTCQB: SNGX) (Soligenix ... developing and commercializing products to treat rare diseases where ... it will be hosting an Investor Webcast Event Friday, ... origins of innate defense regulators (IDRs) as a new ... mucositis and the recently announced and published Phase 2 ...
Breaking Biology Technology: