A long-term study of vitamin A and polychlorinated hydrocarbon levels in otters (Lutra lutra) in south west England.

Seventy-seven wild otters (Lutra lutra) found dead in south west England between 1988 and 1996 were examined post mortem. Liver samples were analysed from 56 otters for polychlorinated hydrocarbons and from 40 for vitamin A (retinol). There was a significant decline in the levels of pollutants over the study period and this coincided with a marked increase in vitamin A levels. However, a causal relationship was not established. Low vitamin A levels were prevalent in the early years of the study but no conclusive pathological lesions due to deficiency were seen. It is suggested that vitamin A deficiency may have been widespread in Britain's otter population until recently and may have been implicated in the earlier decline.