More genetic data are needed before populations are mixed: response to 'Sourcing Eurasian beaver Castor fiber stock for reintroductions in Great Britain and Western Europe'.

ABSTRACT Halley described three options for sourcing Eurasian beavers Castor fiber for reintroduction in Britain and Western Europe: (i) use animals from populations within a single western evolutionarily significant unit (ESU); (ii) mix animals from two or three western ESUs; and (iii) mix animals from eastern and western ESUs. Option three contravenes International Union for Conservation of Nature guidelines, so debate should focus on options one and two. We believe there is a need for further genetic analysis, before a final decision can be made. This decision should not be heavily influenced by cost or be determined by the genotypes of existing captive or escaped populations. [ABSTRACT FROM AUTHOR]