Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Overfishing may diminish genetic diversity even when millions of fish remain

04.11.2002


Populations of marine fish may lose genetic diversity even if fishing stops while there are still several million individuals – a number previously assumed to be enough to preserve a diverse gene pool.



Losing the diversity of key genes can render a population less productive and unable to adapt when faced with challenges such as global warming, pollution or changes in predators or prey. Rare genetic variation of little importance today might be the key to adaptability in the future, according to Lorenz Hauser, University of Washington assistant professor with the School of Aquatic and Fishery Sciences and lead author of a report recently published as part of the Proceedings of the National Academy of Sciences.

It could be that genetic diversity in a population needs to be considered when determining sustainable harvests for marine fish – fish such as snappers, rockfish and cod that spend their entire lives in the ocean. For some animals studied by conservation biologists, such as pandas and elephants, as few as 500 individuals appear to be enough to maintain rare variances.


For reasons not yet understood, however, it appears that in marine fishes only a small proportion of individuals produce large numbers of offspring that survive. Therefore as a fish population declines the number of such capable breeders may reach levels that cannot sustain genetic diversity.

What Hauser and his co-authors found is that the number of capable breeders is several magnitudes smaller than they expected: In their work with a population of New Zealand snapper that was fished down to about 3 million, only one in 10,000 fish was a capable breeder. That means the genetic diversity for a population of a few million fish could be depending on as little as a few hundred fish.

If such low ratios are commonplace in marine species, many other kinds of marine fish stocks may be in danger of losing genetic variability, the paper says. Fish scales collected and archived at the New Zealand Ministry of Fisheries provided DNA from two isolated populations of New Zealand snappers for the research. The smaller population from Tasman Bay lost variations in six of seven gene markers as its numbers declined to 3 million while exploited between the 1950s and 1998. A larger population from Hauraki Gulf, composed of 37 million fish, showed no loss in variation between the 1950s and 1998. However, it had been fished since the late 1800s and by 1950 already had less genetic variation compared to the Tasman Bay population.

From a practical standpoint, fisheries managers are not going to be able to monitor genetic diversity for every stock, Hauser says. Instead, if scientists can learn which fish are the very successful breeders and why, then managers may be better able to predict the number of offspring produced and thus may be able to increase fishing when conditions are favorable for successful fish and decrease fishing when they aren’t.

Hauser was at the University of Hull, England, when the work was conducted in collaboration with Greg Adcock (now of the University of Melbourne), Julio Bernal Ramirez and Gary Carvalho, and their colleague Peter Smith of the National Institute of Water and Atmospheric Research, New Zealand. The study was funded by the Leverhulme Trust, England.


For more information:
Hauser, 206-685-3270, lhauser@u.washington.edu

"Loss of microsatellite diversity and low effective population size in an overexploited population of New Zealand snapper," Proceedings of the National Academy of Sciences, http://www.pnas.org/cgi/content/abstract/99/18/11742


Sandra Hines | EurekAlert!
Further information:
http://www.washington.edu/
http://www.pnas.org/cgi/content/abstract/99/18/11742

More articles from Ecology, The Environment and Conservation:

nachricht International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>