In the 1960s, it was Professor Per Brinck who went out and fished and documented the catches at 200 different locations in Skåne. In the 90s, the test fishing was done again and now it is Associate Professor Anders Persson who will walk in Per Brinck's footsteps and revisit the sites once again.
- Since the 1990s, a lot of money has been invested in wetlands and to facilitate fish to move. Water obstacles have been removed. We want to investigate what the consequences have been in the watercourses, says Anders Persson, associate professor of aquatic ecology.
DNA analysis from mucusThe method used both then and now is electric fishing. All fish are drawn to the net as a magnet when the water turns into a negative pole.
But Anders Persson also has modern technology to his aid. Water samples are taken at each location. DNA analyzes from, among other things, mucus should give answers to the fish species that are present in the watercourse.
- It will be very exciting to see what species we find in water samples compared to when we fish. We have a little fishing as a control.
When SVT meets Anders Persson and his assistants, they are in place in Rönne Å near Kvidinge.
They fish for an area of about 100 square meters. The catch is great, although the fish are small. Electric fishing is only suitable for small fish at the shallower edge.
Some 60 year-old salmon, a number of trout, eels and even some previously red-listed sand crawlers are raised.
- It is interesting that we caught quite a lot of eels. It's nice to see, says Anders Persson.
It is too early to say what answers the test fishing can provide. The project, which is funded by the County Administrative Board and the State Research Council Formas, is ongoing next year.
- I expect that some species have spread significantly more and that other species have been eliminated. But it is difficult to say anything at this stage, says Anders Persson.