We have made no specific assessment of the contribution of the crayfish industry to the UK economy. As part of the development of the Invasive Alien Species (Enforcement and Permitting) Order 2019, we engaged with representatives of the crayfish industry to understand the impact of the Order on their businesses.
The 2010 technical report “The economic cost of invasive non-native species on Great Britain” investigated the cost of signal crayfish to the GB economy in regard to management, riverbank restoration, angling and research. The total cost to GB was found to be £2,689,000 annually (England: £1,538,000; Wales: £576,000; Scotland: £575,000. Northern Ireland has no populations of signal crayfish).
Defra recently published the results of a scoping study documenting the current evidence in relation to the ecosystem service impacts of invasive non-native species (INNS) in the UK. This study sought to determine the feasibility of expanding on the 2010 report by estimating natural capital costs resulting from INNS, alongside the direct economic costs which were the focus of the 2010 report. This found that the costs of control were higher than the reported economic impacts, but these did not include river bank damage or wider ecosystem costs.
 Scoping study: ecosystem services and natural capital costs of invasive non-native species in the UK - BE0162 http://randd.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&Completed=1&ProjectID=20315