The impact of marine vessels on the presence and behaviour of harbour porpoise (Phocoena phocoena) in the waters off Berry Head, Brixham (South West England)

Abstract

Harbour porpoise (Phocoena phocoena) are protected in the UK by the Wildlife and Countryside Act (1981). Understanding the impact of anthropogenic pressures is fundamental for effective protection under this act and successful conservation generally. Land-based observations (n = 146) were conducted over a three-month period, during which, porpoise presence, behaviour, vessel type, and locations were recorded. A total of 2461 behavioural observations were recorded, along with a total frequency of marine vessels of 1377.Principal Component Analysis (76.44%, p = <0.001) revealed a moderate negative correlation between component one (vessels) and two (porpoises and feeding behaviour) (−0.413), indicating that P. phocoena presence and feeding behaviour reduced in response to increasing vessel frequencies. In addition, P. phocoena were sighted more frequently during periods of rising tide at a 1% significance level, consistent with previous results obtained by other Authors.Using measures outlined by the European Commission, the impacts recorded here make this population of porpoises eligible for possible protection under a Special Area of Conservation or for inclusion within the Torbay Marine Conservation Zone as a “priority species”.