New detection method for Goby fish invasion

Ponto-Caspian gobies are a flock of five invasive fish species that have colonized freshwaters and brackish waters in Europe and North America. One of them, the round goby Neogobius melanostomus, figures among the 100 worst invaders in Europe.

Current methods to detect the presence of Ponto-Caspian gobies involve catching or sighting the fish. These approaches are labor intense and not very sensitive. Consequently, populations are usually detected only when they have reached high densities and when management or containment efforts are futile.

Researchers of the Department of Environmental Sciences of the University of Basel have now developed a test that allows for the detection of Ponto-Caspian gobies in streaming and stagnant water.

With a commercially available, though slightly modified, water column sampler, water samples are taken from the bottom of the water body, where invasive gobies live. Via feces or scales, the fish release so-called environmental DNA into the stream. The water samples are then analyzed for traces of this so-called eDNA in the lab. The test developed at the University of Basel reacts exclusively to the genetic material of Ponto-Caspian gobies, but not to domestic fish species.

The procedure is less time and cost-intensive than angling, and the samples can even be drawn by untrained individuals. Unlike electrofishing, the method does not impact the fish fauna and can consequently be used in protected zones and breeding grounds.