Lutra 50(1)_Robinson et al_2007

The summer distribution and occurrence of cetaceans in the coastal waters of the outer southern Moray Firth in northeast Scotland (UK)

Information on the distribution and occurrence of whales, dolphins and porpoises in the coastal waters of Scotland’s Moray Firth, in the north-west North Sea, remains fairly sparse to date, with few detailed studies being conducted on species other than the bottlenose dolphin (Tursiops truncatus). Consequently, familiar coastal species such as the minke whale (Balaenoptera acutorostrata) and harbour porpoise (Phocoena phocoena) have received far less attention in these waters, and yet these and other species may be of considerable conservation priority. In the present study, an examination of the animals using the southern coastal waters of the outer Moray Firth was carried out between May and October 2001 to 2005 inclusive. During 9,663 km of dedicated boat survey effort, 751 encounters were recorded with eight different species (six species of toothed whale, and two species of baleen whale) in an 880 km square coastal study area between Fraserburgh and Lossiemouth. The most commonly sighted cetaceans were harbour porpoises (comprising 60% of all encounters) and minke whales (at 25%), but the two most abundant species were porpoises and bottlenose dolphins, jointly accounting for 89% of the total animals encountered. Considerable inter-annual and seasonal variation was observed in both the number of encounters and the diversity of species recorded, and a seasonal increase in harbour porpoises was noted, with inshore movements of females and their calves across the summer months. For each of the other species recorded, all were considered “pelagic”, deeper water animals which only sporadically utilised the study site. The temporal and spatial occurrences of the principal coastal species are discussed with respect to the complex ecological, biological and anthropogenic determinants in this location. Recommendations for the subsequent monitoring of this cetacean community are considered to be particularly important for current and future conservation strategies. Further work integrating broader scale survey coverage is proposed, with more detailed studies in particular areas of focal interest or concern with respect to local management and/or conservation directives.