Aquatic Conservation-marine and Freshwater Ecosystems | 2019
Habitat use of a coastal delphinid population investigated using passive acoustic monitoring
Abstract
1 \uf0b7 The population of bottlenose dolphins in eastern Scotland has undergone significant 2 range expansion since the 1990’s, when a special area of conservation was established for 3 the population. 4 \uf0b7 Distribution of this population is well described within areas of its range, where intensive 5 work has been carried out, such as the inner Moray Firth, St Andrews Bay, and the Tay 6 estuary area. However, elsewhere in their range, habitat use is less well understood. 7 \uf0b7 In this study, a large-scale and long-term passive acoustic array was used to gain a better 8 understanding of bottlenose dolphin habitat use in eastern Scottish waters, 9 complementing and augmenting existing visual surveys. 10 \uf0b7 Data from the array were analysed using a three-stage approach. First, acoustic 11 occupancy results were reported; second, temporal trends were modelled; and third, a 12 spatial-temporal-habitat model of acoustic occupancy was created. 13 \uf0b7 Results from the acoustic occupancy are in agreement with visual studies that found areas 14 near known foraging locations were consistently occupied. Results from the trend 15 2 analysis were inconclusive. Habitat modelling showed that, throughout their range, 16 bottlenose dolphins are most likely to be detected closer to shore, and, for a constant 17 distance to shore, in deeper water. 18