Manx government scientists say water quality in the Isle of Man's rivers has improved slightly over the last year.
The latest interim report on river water quality has been released by the Department of the Environment, Food and Agriculture.
The data suggests the Island's rivers have been getting worse for a decade, but this year's results have given some cause for optimism.
The tests results are banded together into five-year blocks because individual good or bad years could skew the figures.
The results for 2007 to 2011 show 63 per cent of Manx watercourses are of very good quality, reversing a downward trend from sampling in the previous five years.
In his report, freshwater biologist and environmental protection officer Dr Calum MacNeil says the news is encouraging.
He suggests the changes could be down to a changing, drier climate or a fall in the amount of pollution put into rivers by industry
(Picture: Heptageniidae mayfly nymph, which DEFA says is typical of 'very good' rivers).