A recent Environment Agency survey has shown that Lancashire and South Cumbrian otters numbers are growing from strength the strength.
In May this year Environment Agency officers donned their wellies and waders in the hunt for these elusive mammals along the River Lune including its tributaries.
Alison Whalley, who organised the survey said: “As otters are nocturnal and elusive we were looking for secondary signs of otters including their spraints (poo) and footprints.
“We are very pleased with the findings as it shows that the Lune’s otter population, compared to the 2004 survey, has now spread to new sites including the River Keer as well as an increased population around Tebay, Sedbergh, High Bentham and Kirby Lonsdale.â€
These positive results show that the Lune otters are steadily recovering from over five decades of decline due to chemicals entering rivers including organochlorine*, used for sheep dip in the 1950s, and PCBs (polychlorineated biphenyls).
John Collins, Lancashire Area Manager, said: “It is very important that we monitor the otter populations in this region. As top predators, if otters are thriving, it means our rivers are healthy.â€
The decline of otters in the UK began in the 1950s with the introduction of organochlorine pesticides such as sheep dip and seed dressing. These chemicals accumulated and had serious repercussions, from acute toxicity to chronic infertility, therefore reducing the population.
The use of organochlorines has declined over the years and so its effects on the environment have reduced. However, in the 1960s, otters were faced with a new chemical threat of PCB’s (polychlorinated biphenyls). This is another toxic chemical, persistent in the environment, but the effects of which are not fully understood.
Studies carried out over the past decade found high levels of both organochlorines and PCB’s in otter’s livers, although levels are decreasing.
By the mid 1970’s the UK otter population had been greatly reduced, and only remnant populations remained in most of the country with the exception of upland areas, and the coasts and islands of Scotland.
