Observations on an otter population in decline

The distribution of otter signs on the catchment of the River Teme, United Kingdom, over a ten years period indicated that the range of the species, already limited at the start of the study in 1977, declined further over subsequent years. Otters became restricted to the upper reaches of the catchment. Evidence is presented that contamination with organochlorines (which can be extracted from spraints) may have been responsible for the decline. Reasons for a possible increase in otter distribution during the final years of the study are discussed.