Factors affecting the success of an otter (Lutra lutra) reinforcement programme, as identified by post-translocation monitoring

Formerly widespread throughout much of the UK, the otter underwent a rapid decline in numbers from the 1950s to the 1970s, caused primarily by the introduction of organochlorine-based pesticides and exacerbated by hunting and loss of habitat. The first national otter survey of England in 1977-79 showed that the only significant populations remaining were along the Welsh borders and in the south west, with only very isolated and fragmented populations elsewhere. For this reason, a reinforcement and monitoring project was set up to improve populations numbers.