"We analysed seawater samples specifically for fish DNA and we were very surprised when the results started to show up on the screen. We ended up with DNA from 15 different fish species in water samples of just a half litre. We found DNA from both small and large fish, as well as both common species and rare guests. Cod, herring, eel, plaice, pilchard and many more have all left a DNA trace in the seawater," says Philip Francis Thomsen.
In the other study the researchers showed that it is also possible to obtain DNA from harbour porpoise in small water samples taken in the sea, so the approach is not only limited to fish, but can also track large marine mammals.
A new and efficient method
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. Associate Professor and fish expert Peter Rask Mller from the National History Museum of Denmark, who also participated in the study, is optimistic.
"The new DNA method has very interesting perspectives for monitoring marine fish. We always keep our eyes open for new methods to describe marine fish biodiversity in an efficient and standardised way. Here, I look very much forward to follow the DNA method in the future, and I think it could be very useful to employ in oceans around the world," says Peter Rask Mller.
The researchers also see great perspectives in the method for estimating fish stocks in the future.
|Contact: Philip Francis Thomsen|
University of Copenhagen