OTTERS AND EELS: LONG-TERM OBSERVATIONS ON DECLINES IN SCOTLAND

The summer diet of otters Lutra lutra has been monitored for almost forty years in a study area in NE Scotland. Since 2000, otter numbers and reproduction in the area have declined. At the same time the occurrence of eels (Anguilla anguilla) in otter faeces or 'spraints', formerly the otters' dominant prey, decreased substantially. This is seen against a well-documented sharp, probably global decline in numbers of eel. Otter predation on young water birds in the study area increased, as has predation on other fish species, and changes in importance of other prey are also documented. It is suggested that with otters being food- limited, the decline in eels should be of serious concern to otter conservationists.

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