Action: Ponto-Caspian gobies: Use of barriers to prevent migration
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- A controlled, replicated field study in the USA, found that an electrical barrier prevented movement of round gobies across it, and that increasing electrical pulse duration and voltage increased effectiveness of the barrier.
A number of different systems can be used to prevent dispersal of fish to new habitats, or to prevent their migration. For example, a replicated study from the USA found that leaf litter could act as a barrier, preventing dispersal of the eastern mosquitofish Gambusia holbrooki (Alemadi & Jenkins 2008). Another controlled study from the USA found that sound bubble barriers prevented Asian carp (Cyprinidae) from moving upstream (Ruebush et al. 2012). Other systems include altered flow rates. However, one study concluded that water flow rates faster than 125 cm/second, along with a route free from rest and refuge areas, would be necessary to prevent round goby Neogobius melanostomus migrating upstream (Tierny et al. 2011). This was because round gobies were found to be able to hold their position in strong water currents for extended periods using their pectoral fins as brakes, and could recover rapidly from exhaustive exercise, achieving powerful speed bursts (Tierny et al. 2011). Other systems that can be used to prevent fish migration include electrical barriers.
Alemadi S.D. & Jenkins D.G. (2008) Behavioral constraints for the spread of the eastern mosquitofish, Gambusia holbrooki (Poeciliidae). Biological Invasions, 10, 59-66.
Ruebush B.C., Sass G.G., Chick J.H. & Stafford J.D. (2012) In-situ tests of sound-bubble-strobe light barrier technologies to prevent range expansions of Asian carp. Aquatic Invasions, 7, 37-48.
Tierny K.B., Kasurak A.V., Zielinski B.S. & Higgs D.M. (2011) Swimming performance and invasion potential of the round goby. Environmental Biology of Fishes, 92, 491-502.
Supporting evidence from individual studies
A controlled, replicated field study in the Shiawassee River, Michigan, USA (Savino et al. 2001) found that an electrical barrier prevented round goby Neogobius melanostomus movement across it. Without any electrical current, round goby crossed the barrier within 20 minutes from release upstream. Using electrical settings shown to inhibit passage in the laboratory, the only marked round goby found below the barrier were dead. At reduced pulse durations, a few round goby (on average one per test) were found alive, but debilitated, below the barrier. Increasing electrical pulse duration and voltage increased the effectiveness of the barrier. Feasibility studies in a 2 m donut-shaped tank determined the required electrical currents. In field studies, an electrical barrier was placed between two blocking nets. The barrier consisted of 6 m wide canvas on which were laid four cables carrying the electrical current. Twenty five latex paint-marked round goby were introduced upstream of the electrical barrier and recovered 24 h later upstream, on or downstream of the barrier.
(1)Savino J.F., Jude D.J & Kostich M.J. (2001) Use of electric barriers to deter movement of round goby. American Fisheries Society Symposium, 26, 171-182