Distribution and relative abundance of harbour porpoises (Phocoena phocoena L.), white-beaked dolphins (Lagenorhynchus albirostris Gray), and minke whales (Balaenoptera acutorostrata Lacepède) around the British Isles

Abstract

Distributional data for three cetacean species, harbour porpoise (Phocoena phocoena), white-beaked dolphin (Lagenorhynchus albirostris), and minke whale (Balaenoptera acutorostrata), are presented from sightings around Britain and Ireland made during seabird surveys at sea. No attempt is made to estimate the absolute numbers or density of animals present, but the distribution and relative abundance of these three species are plotted in terms of the numbers of animals seen per kilometre surveyed. The number of animals seen is adjusted for sea state to allow for differences in detectability of cetaceans under different weather conditions. A geographical information system is used to display the sighting rates in 1-degree rectangles seasonally and for the entire year. Areas of north-western European shelf waters that appear to be most important for these three species are the western side of the northern North Sea, the Hebrides, and, for porpoises, south-western Ireland and the southern Irish Sea.