Scientists question widely adopted indicator of ocean healthNovember 21st, 2010 - 1:21 pm ICT by ANI
London, Nov 21 (ANI): A new analysis by an international team led by a University of Washington fisheries scientist has suggested that the most widely adopted measure for assessing the state of the world’s oceans and fisheries led to inaccurate conclusions in nearly half the ecosystems where it was applied.
“Applied to individual ecosystems it’s like flipping a coin, half the time you get the right answer and half the time you get the wrong answer,” said Trevor Branch, a UW assistant professor of aquatic and fishery sciences.
In 1998, the journal Science published a groundbreaking paper that was the first to use trends in the trophic levels of fish that were caught to measure the health of world fisheries.
The trophic level of an organism shows where it fits in food webs, with microscopic algae at a trophic level of one and large predators such as sharks, halibut and tuna at a trophic level of around four.
The 1998 paper relied on four decades of catch data and averaged the trophic levels of what was caught. The authors determined those averages were declining over time and warned we were “fishing down the food web” by overharvesting fish at the highest trophic levels and then sequentially going after fish farther down the food web.
Twelve years later, newly compiled data has emerged that considers such things as the numbers and types of fish that actually live in these ecosystems, as well as catch data.
An analysis reveals weaknesses in assessing ecosystem health from changes in the trophic levels of what is being caught.
The study appears in the Nov. 18 issue of Nature. (ANI)
- Is overfishing killing the hilsa in Bengal? (With Image) (June 5 is World Environment Day) - Jun 05, 2012
- New approach to ease the oceans from overfishing, pollution and human impact - Sep 15, 2010
- Fishermen snare 881-pound tuna & feds take it away - Nov 23, 2011
- Fukushima-contaminated tuna caught off San Diego coast - May 29, 2012
- Scientists develop method to assess ecological risk - Oct 29, 2009
- Gujarat coral reefs a virtual gold mine - Mar 27, 2011
- Most fisheries management regimes lag behind international standards - Jun 23, 2009
- No fish will be left to catch, expert warns Bangladesh - Feb 01, 2011
- Time to focus on freshwater fish, is India listening? - Oct 25, 2010
- Early warning signal for ecosystem collapse detected by scientists - Apr 29, 2011
- World's fisheries can recover under appropriate management - Jul 31, 2009
- What's good for women's heart? Baked mackerel! - May 25, 2011
- Humans as predators led to the extinction of woolly mammoths - Jul 03, 2010
- Blue fin tuna is one step closer to extinction: Greenpeace - Jun 11, 2010
- 20th-century warming in Lake Tanganyika endangers fish, livelihoods - May 18, 2010
Tags: assistant professor, ecosystems, fisheries scientist, fishery sciences, food web, food webs, half the time, halibut, inaccurate conclusions, journal science, microscopic algae, ocean health, oceans and fisheries, organism, trophic level, trophic levels, twelve years, types of fish, world fisheries, wrong answer