Navigation Links
Scientists question fisheries health test

A measure widely advocated as a means of assessing the health of marine ecosystems is an ineffective guide to trends in biodiversity, and more direct monitoring is needed, a new study has found. The findings published this week in Nature followed an examination of whether changes in fishery catches reflect changes in the structure of marine food webs, and therefore are a suitable guide to assess the impacts of fishing on marine ecosystem health.

CSIRO Wealth from Oceans Flagship scientist, Dr Beth Fulton, and Dr Sean Tracey from the Tasmanian Aquaculture and Fisheries Institute at the University of Tasmania, were members of the international team involved in the study.

"Biodiversity indicators are used to track the impacts of fishing as a guide to management effectiveness," Dr Fulton said.

"The most widely adopted indicator of biodiversity in the ocean at a global scale is the 'average trophic level' (position in the food chain) determined from fishery catches.

"This is intended to detect shifts from high-trophic-level predators such as Atlantic cod and tunas to low-trophic-level fish, invertebrates and plankton-feeders such as oysters." Dr Tracey said the study was the first large-scale test of whether average trophic level determined by fishery catch is a good indicator of ecosystem average trophic level, marine biodiversity and ecosystem status.

"We looked at average trophic level determined from a range of sources including global fishery catches, long-term surveys, stock assessments and complex computer modelling for marine ecosystems around the world," Dr Tracey said.

"In contrast to previous findings, which reported declines in catch average trophic level thought to be due to the loss of large fish and the increasing catch of small fish, we found that catches are increasing at most levels of marine food webs and that the average trophic level has actually increased in the past 25 years.

"We also found that average trophic level determined from fishery catches does not reliably measure the magnitude of fishing impacts or the rate at which marine ecosystems are being altered by fishing."

Dr Tracey says global fisheries are at a crucial turning point, with high fishing pressure being offset in some regions by rebuilding efforts. Relying on the average trophic level of catch could mislead policy development.

Dr Fulton said that, to target limited resources in the best way, researchers should focus on assessing species vulnerable to fishing that are not currently assessed effectively

"We also need to develop and expan trend-detection methods that can be applied more widely, particularly to countries with few resources for science and assessment.

"Through such efforts we can better detect and convey the true impact of fisheries on marine biodiversity," Dr Fulton said.

Led by University of Washington fisheries scientist, Trevor A. Branch, the study's findings are published in a letter in Nature entitled: "The trophic fingerprint of marine fisheries".


Contact: Bryony Bennett
CSIRO Australia

Related biology news :

1. Scientists clock on to how sunlight shapes daily rhythms
2. Scientists discover genes linking puberty timing to body fat in women
3. Bacteria use toxic darts to disable each other, according to UCSB scientists
4. Scientists question indicator of fisheries health, evidence for fishing down food webs
5. Scientists learn more about how kidneys fail and how new drugs may intervene
6. Scripps Research scientists identify new mechanism regulating daily biological rhythms
7. Caltech scientists describe the delicate balance in the brain that controls fear
8. UNC scientists identify cellular communicators for cancer virus
9. Scientists discover how the songbirds brain controls timing during singing
10. Scientists pinpoint key defense against parasite infection
11. McMaster scientists turn skin into blood
Post Your Comments:
(Date:3/31/2016)... March 31, 2016   ... or the "Company") LegacyXChange is excited to ... its soon to be launched online site for trading ... ) will also provide potential shareholders a sense ... technology to an industry that is notorious for fraud. ...
(Date:3/29/2016)... , March 29, 2016 ... "Company") LegacyXChange "LEGX" and SelectaDNA/CSI Protect are pleased to ... ink used in a variety of writing instruments, ensuring ... of originally created collectibles from athletes on LegacyXChange will ... analysis of the DNA. Bill Bollander ...
(Date:3/22/2016)... , March 22, 2016 ... report "Electronic Sensors Market for Consumer Industry by Type ... Others), Application (Communication & IT, Entertainment, Home ... Global Forecast to 2022", published by MarketsandMarkets, ... expected to reach USD 26.76 Billion by ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... ... innovative medical technologies, services and solutions to the healthcare market. The company's primary ... various distribution, manufacturing, sales and marketing strategies that are necessary to help companies ...
(Date:6/24/2016)... discussions on a range of subjects including policies, debt and ... Poloz. Speaking at a lecture to the Canadian ... to the country,s inflation target, which is set by both ... "In certain areas there needs to be ... why not sit down and address strategy together?" ...
(Date:6/23/2016)... ... June 23, 2016 , ... ... its second eBook, “Clinical Trials Patient Recruitment and Retention Tips.” Partnering with experienced ... this eBook by providing practical tips, tools, and strategies for clinical researchers. , ...
(Date:6/23/2016)... , June 23, 2016 A person commits ... the crime scene to track the criminal down. ... U.S. Food and Drug Administration (FDA) uses DNA evidence to ... Sound far-fetched? It,s not. The FDA has ... to support investigations of foodborne illnesses. Put as simply as ...
Breaking Biology Technology: