Controlling Invasives, Saving Natives

Invasive crayfish are one of the biggest threats to aquatic ecosystems worldwide. They can cause major adverse effects on native crayfish, invertebrates, fish and plant communities. In the UK signal crayfish have been responsible for a massive decline in our native white-clawed crayfish due to competition and transmission of a deadly disease, crayfish plague.

As a result of my own research and that of others, I can provide realistic advice. There is no silver bullet (yet – but check this out) and many believe that the eradication of invasive crayfish is impossible – they could be right! Successful control projects tend to have three things in common: 1) they are capable of continuing long term, i.e. 5 – 20 years; 2) they use a combination of methods aimed at targeting all life stages; and 3) they have the capacity to adapt their methods in response to results. Using this approach there maybe opportunities to contain the expansion of invasive crayfish and therefore protect vulnerable features such as salmonid spawning habitats or native crayfish populations, or maybe eradicate a newly established signal crayfish population.

If invasive crayfish control is not feasible, translocation to a safe ‘Ark’ site may protect native crayfish at risk. Captive breeding and reintroduction is another option. The newly published Crayfish Conservation Manual includes comprehensive guidance on ark sites and captive breeding and can be purchased here