Action: Ponto-Caspian gobies: Changing salinity
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- A replicated, controlled laboratory study in Canada found 100% mortality of round gobies within 48 hours of exposure to water of 30% salinity.
Changing the salinity of an invaded waterbody may offer a tool for localised eradication or population reduction of gobies, provided potentially negative effects on native species are managed carefully. Increasing the salinity to a very high level is likely to have significant effects on non-target species.
Supporting evidence from individual studies
A replicated, controlled laboratory study from 2006 to 2007 at the Great Lakes Institute for Environmental Research in Canada (Ellis & McIsaac 2009) found that round gobies Neogobius melanostomus cannot survive for more than two days in water with 30% salinity. All fish survived five hours in water of 30% salinity. It did not make a difference if the water became salty gradually or immediately. Up to about a fifth of the fish were still alive after 24 hours. However, after 48 hours, all fish were dead. Gobies were taken from a river in Canada. Ten gobies were put in each of 12 aquaria containing 16 litres of filtered river water. The water in four of the aquaria had 30% salinity from the beginning. The salinity in another four aquaria was 4% at the start of the experiment and increased every hour to 8, 14, 24 and 30%. Every hour for five hours, and after 24 and 48 hours, dead gobies were removed and counted.