Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gene research warning for commercial fishing

13.08.2002


Commercial fishing practices can reduce genetic diversity in fish populations, possibly threatening their productivity and adaptability to environmental change, new research has found.



An Australian zoologist now at the University of Melbourne, along with colleagues from the United Kingdom and New Zealand, was the first to record a decline in the genetic diversity of a commercially exploited marine species.

Their findings, published in the latest volume of the "Proceedings of the National Academy of Sciences", shout a warning that could force a rethink to current fisheries management and the research focus into sustainable fishing.


Dr Greg Adcock analysed the DNA found in scales preserved from two populations of New Zealand snapper collected from the 1950s to 1998. One population had been commercially fished since the late 1800s. The other was a ’virgin’ population, being subjected to subsistence and recreational fishing only until the scale collection began.

Adcock and colleagues found that the virgin population from Tasman Bay on New Zealand’s South Island had suffered an unexpected decline in genetic diversity, starting from the time it began to be commercially exploited in the 1950s.

The other population, from the North Island’s Hauraki Bay, showed no decline in genetic diversity in the nearly 50 years to 1998.

The paper reports that the Tasman Bay’s effective population size (the number of fish in the population capable of breeding) is 100,000 times fewer than its total number, and several orders of magnitude lower than expected.

"In Tasman Bay, commercial fishing has often reduced total numbers to as low as about one million. This leaves only a few hundred fish to contribute to the next generation, a dangerously low genetic base from which to sustain a population," says Adcock.

Less diversity means less adaptability

"With a high effective population you can retain a large amount of rare genetic variation. Such variation is lost as numbers decline. A rare variant may not play a significant role in the current environment, but if a fish population loses a large number of these genes, such as happened in Tasman Bay, they risk losing the ability to adapt to changes such as global warming, pollution and human induced changes to predator and prey populations," he says.

Adcock points to recent assertions that ocean warming is suspected of causing recruitment failure of cold-adapted North Sea cod.

"Until now nobody suspected that any loss of diversity was happening as it was thought that even in over-fished populations where their numbers are still be in the millions, that there would still be a sufficiently large effective population to prevent declines in genetic diversity," says Adcock.

"A population of several million may actually be in danger of losing genetic variability, which may have long-term consequences," he says.

"Genetic diversity should become a management consideration in many exploited marine species. Many fully exploited or over-fished stocks may be already suffering loss of diversity.

"We don’t know yet the minimal level of genetic diversity required to sustain a commercial fishery long-term, but there is enough evidence now to suggest we need to be cautious and begin to reassess our understanding of fishery management and the sustainability of the industry."

How genetic diversity was measured

To assess the loss of genetic diversity, Adcock and his colleagues studied seven regions of the snapper’s chromosomes, known as microsatellite loci, which are highly variable and mutate at high rates.

The high rates of mutation in microsatellites produce the levels of variation required for researchers to work out how long ago two or more populations or species diverged from a common population or ancestor. In this case, Adcock and colleagues used this variation to assess the changes in genetic diversity over time.

The Tasman Bay population showed a significant decline in diversity in six of the seven loci.

To explain why Hauraki Gulf failed to show any loss of genetic diversity, Adcock contends that the genetic variation had already been lost in the early years of intensive fishing, prior to 1950.

"Hauraki Gulf is a larger population than Tasman Bay and should naturally retain more genetic variation. When the study began, however, its variation was lower than Tasman Bay’s," he says.

Adcock believes the findings open up exciting possibilities of further research and collaboration with the various fishing industry bodies.

"A close collaboration between fishery biologists, geneticists and the fishing industry would be required to carry out research into the biology and behaviour of marine species and their possible implications for fisheries management and conservation," he says.

Adcock’s colleagues from Hull University (UK) were Lorenz Hauser (now at the University of Washington), Julio Bernal Ramirez and Gary Carvalho, and from New Zealand, Peter Smith of the National Institute of Water and Atmospheric Research.


More information

Dr Greg Adcock
University of Melbourne
Telephone +(61 3) 8344 4346/4351 or 9434 1844
E-mail gjadcock@unimelb.edu.au

Jason Major
Media officer, Communications and Marketing
The University of Melbourne
Telephone +(61 3) 8344 0181 or 0421 641 506
Fax +(61 3) 9349 4135
E-mail jmajor@unimelb.edu.au

Jason Major | EurekAlert!
Further information:
http://www.unimelb.edu.au/

More articles from Life Sciences:

nachricht A one-way street for salt
21.09.2018 | Julius-Maximilians-Universität Würzburg

nachricht Nerve cells in the human brain can “count”
21.09.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists present new observations to understand the phase transition in quantum chromodynamics

The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.

This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.

Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

Im Focus: New devices based on rust could reduce excess heat in computers

Physicists explore long-distance information transmission in antiferromagnetic iron oxide

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.

Im Focus: Finding Nemo's genes

An international team of researchers has mapped Nemo's genome

An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

 
Latest News

Fraunhofer ISE with over 60 Contributions at the European PV Solar Energy Conference and Exhibition

21.09.2018 | Trade Fair News

558 million-year-old fat reveals earliest known animal

21.09.2018 | Earth Sciences

Neutrons produce first direct 3D maps of water during cell membrane fusion

21.09.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>