10.4. Threat: Invasive fish

10.4.1 Brown and black bullheads Beneficial ● Application of a biocide Two studies in the UK and USA found that rotenone successfully eradicated black bullhead. Assessment: beneficial (effectiveness 80%; certainty 80%). https://www.conservationevidence.com/actions/1050 Likely to be beneficial ● Netting A replicated study in a nature reserve in Belgium found that double fyke nets could be used to significantly reduce the population of large brown bullheads. Assessment: likely to be beneficial..