New DNA-method tracks fish and whales in seawater

Danish researchers at University of Copenhagen lead the way for future monitoring of marine biodiversity and resources by using DNA traces in seawater samples to keep track of fish and whales in the oceans. Half a litre of seawater can contain evidence of local fish and whale faunas and combat traditional fishing methods. Their results have been published in the international scientific journal PLOS ONE.

"The new DNA-method means that we can keep better track of life beneath the surface of the oceans around the world, and better monitor and protect ocean biodiversity and resources," says PhD student Philip Francis Thomsen of the University of Copenhagen’s Centre for GeoGenetics at the Natural History Museum of Denmark.

Marine ecosystems worldwide are under threat with many fish species and populations suffering from human over-exploitation, which greatly impacts global biodiversity, economy and human health. Today, marine fish are largely surveyed using selective and invasive methods mostly limited to commercial species, and restricted to areas with favourable conditions.

However, researchers at Centre for GeoGenetics now lead the way for future monitoring of marine biodiversity. They have shown that seawater contains DNA from animals such as fish and whales. The species leave behind a trace of DNA that reveals their presence in the ocean based on water samples of just half a litre.

The study also compares the new DNA method with existing methods traditionally used for monitoring fish such as trawl and pots. Here, the DNA method proved as good as or mostly better than existing methods.

Moreover, the DNA method has a big advantage that it can be performed virtually anywhere without impacting the local habitat – it just requires a sample of water.

Read the full story on the website of the University of Copenhagen.

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