Conservation of European Freshwater Crayfish

Freshwater crayfish are keystone species in European freshwater ecosystems. As ecosystem engineers, they have a high impact on freshwater ecosystem biodiversity. Additionally, they have a high economic value as a human food delicacy. Unfortunately, population trends of native crayfish all across Europe are in severe decline. The main threats they are exposed to are the increasing populations of invasive North American crayfish, which are vectors of the crayfish plague pathogen Aphanomyces astaci, an oomycete listed amongst the 100 worst invasive species worldwide. North American crayfish species are usually resistant towards the crayfish plague disease. For European crayfish, however, A. astaci is a highly infectious pathogen. The high financial and cultural values of the freshwater crayfish in Europe and the devastation of the native crayfish stocks during the 20th century encouraged fisheries officers and researchers in several European countries to introduce alien freshwater crayfish into Europe.

Currently, the native European crayfish species are on the brink of extinction. The alien crayfish species, which were supposed to replace the eradicated native stocks, not only transfer the deadly disease but also ecologically outcompete their native crayfish counterparts. In this Research Topic, we envisage collecting scientific work on crayfish conservation from multiple scales, ranging from molecular to species and evolutionary levels, to address the ecological and economic consequences of invasive crayfish and host-parasite interactions on European freshwater biodiversity and ecosystem functioning. Recent advances in genomic and transcriptomic work on freshwater crayfish will be highly useful to identify target genes and molecular pathways, which underlie the defense mechanisms of the crayfish immune system and might be responsible for increased resistance towards crayfish plague infection. The results might become the basis of selective breeding and reintroduction programs. Ultimately, this Research Topic aims to aid the conservation and management of European freshwater crayfish to prevent them from extinction.

We invite researchers to contribute original research articles, reviews and opinion papers on the following topics:

• Population genetics/genomics of native and alien freshwater crayfish in Europe
• Crayfish and the crayfish plague: host-parasite coevolution
• Crayfish immune system
• Ecological interactions of native and alien freshwater crayfish
• Crayfish management and reintroduction
• Advances in aquaculture and selective breeding
• Economic consequences of invasive crayfish on European freshwater biodiversity and ecosystem functioning
• Historical and cultural use of crayfish in Europe