Otters – History of Dorset Otter Group

A short history of the Dorset Otter Group – and fond memories of Peter Irvine

Following the catastrophic crash of otter numbers in the late 1950’s due to poisoning by organochlorines, very few otters were being reported in the county by the 1970s. A few otters had been released on the Stour in the 1980s but, by the mid 1990s, we really had no idea about the status of this iconic species in Dorset.

Hampshire, Somerset and Devon all had volunteers on the lookout for otters and, in 1997, Dorset Wildlife Trust decided to fill the gap in this recording network by setting up a Dorset Otter Group (DOG). John Stobart (now with Natural England and also County Mammal Recorder) became the first Rivers and Wetlands Officer and supported DOG by training new surveyors and co-ordinating record collection.

Photo: Colin Varndell

John designed a simple spot check methodology to record presence or absence of otter. Bronwen Bruce took over in 1999 and then Rachel Janes in 2004. It is estimated that, between them, they trained over 500 volunteers in otter surveying techniques, namely spraint (droppings) and identification of tracks and signs. At best, around 80 registered surveyors submitted records four times per year from up to 250 sites across the county. DOG provided the county with a 14- year continuous dataset shared with Dorset Environmental Records Centre, which enables the Environment Agency (EA), planners, developers etc to make informed decisions and to assess whether we are reaching current Government targets. Continued monitoring of the otter will be necessary if we are to minimise the risk of another environmental disaster, such as that of the 1950s, unfolding without our knowledge.

DOG was extremely fortunate to have attracted a group of exceptional volunteers, with many of the original members very active in the group throughout. A key member was Peter Irvine, who sadly died in May 2007. Peter attended the first DOG training workshop and immediately took on the responsibility of the group’s newsletter. Peter developed this publication into ‘The Holt’ and even developed his own cartoon otter alter-ego, ‘Potter’. DOG members still miss his enthusiasm, knowledge and passion.

The otter’s recovery started well before DOG was established but the group witnessed the latter stages of this process and, by 2010, it was clear that otters were present (at least in the sense that they regularly visit) on almost every usable watercourse in the county. Extensive research into Parish Records carried out by Peter Irvine lead to the publication of ‘Dorset Otter Records (1700-1999)’ (needs a reference or link – I will find this and create a .pdf file) and provided us a benchmark for healthy populations. From this, we know that otters were once found even in coastal areas such as Chapman’s Pool on Purbeck whereas today the evidence is sparse from such coastal streams. We don’t know the true carrying capacity of our catchments for otters in current conditions – these are very different in terms of water quality, prey density and hazard (principally traffic) to those of the 18th and 19th centuries – but there may still be scope for further expansion of otter territories. Recent sightings in Weymouth, Swanage and West Bay encourage speculation that the sea is being used more than we know and there is much more investigative work to be done.

In addition to the extensive record collection, DOG members built artificial otter holts, publicised otters through displays at shows and river walks, worked with EA regarding issues of fisheries predation, and in advising on measures to reduce otter road deaths.

During the fourteen years of its existence, DOG was supported by Bournemouth and West Hampshire Water, Wessex Water and principally by the EA, who were interested in otters because of their position as a top predator in aquatic systems and therefore an excellent indicator of water quality. However, due to ever increasing competition for monies, DEFRA cuts and to the very success of this mammal’s recovery making otters less attractive to funders, the DWT found it progressively more difficult to offer support and decided to hand the baton on to the Dorset Mammal Group.