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 Listening in: Acoustic monitoring devices detect illegal hunting and logging
14.12.2017 | Gesellschaft für Ökologie e.V.

nachricht How fires are changing the tundra’s face
12.12.2017 | Gesellschaft für Ökologie 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: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>