Philipp Hirsch: Species-Specific Barriers To Stop The Upstream Dispersal Of Invasive Gobies
Channel: Fishbase Sweden
Date: 08/11/2019

Philipp Hirsch, Bavarian State Collection of Zoology, Germany, gave a lecture titled "Unauthorized Entry Prohibited! Research Towards Species-Specific Migration Barriers To Stop The Upstream Dispersal Of Invasive Gobies" at FishBase Symposium 2019 in Stockholm, Sweden, 21 October 2019.

ABSTRACT: Man-made barriers in rivers are a major conservation issue in fish biology because they impede fish migrations to upstream spawning grounds. Most research focuses on how such barriers can be re-designed to facilitate fish migrations e.g. via fish ladders. Invasive gobies, native to the Ponto-caspian area, are currently spreading into upstream river at both sides of the Atlantic. In this situation, the re-design of the barriers could give reasons for a re-think: wouldn’t it be ideal to keep the blocking function for the invasive species, whereas native species would be able to overcome the barrier?

To answer this question, we conducted research aimed at exploring the possibilities of a species-specific migration barrier. 

In this talk, I will present data on recent research towards a species-specific migration barrier. We conducted swimming speed experiments in a swimming chamber using the invasive round goby (Neogobius melanostomus) and two native species: the bullhead (Cottus gobio) and the gudgeon (Gobio gobio). Based on these experimental data, we constructed a barrier-prototype to be applied in a vertical-slot fish pass. We tested this barrier in dispersal experiments at different flow velocities in a life-sized model of such a fish pass and monitored the behavior and the dispersal success of all three species.  The results show that the native gudgeon could pass through the barrier at the highest tested velocities, whereas the round goby, but also the native bullhead could not.

These results highlight the need for more research and point towards a promising avenue for finding novel solutions to invasive species management.