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 From the Arctic to the tropics: researchers present a unique database on Earth’s vegetation
20.11.2018 | Martin-Luther-Universität Halle-Wittenberg

nachricht Fading stripes in Southeast Asia: First insight into the ecology of an elusive and threatened rabbit
20.11.2018 | Forschungsverbund Berlin e.V.

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: Nonstop Tranport of Cargo in Nanomachines

Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.

Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Coherence Tomography: German-Japanese Research Alliance hosted Medical Imaging Conference

19.11.2018 | Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

 
Latest News

When AI and optoelectronics meet: Researchers take control of light properties

20.11.2018 | Physics and Astronomy

Researchers use MRI to predict Alzheimer's disease

20.11.2018 | Medical Engineering

How to melt gold at room temperature

20.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>