title: Passive acoustic methods for fine-scale tracking of harbour porpoises in tidal rapids.
abstract: The growing interest in generating electrical power from tidal currents using tidal turbine generators raises a number of environmental concerns, including the risk that marine mammals might be injured or killed through collision with rotating turbine blades. To understand this risk, information on how marine mammals use tidal rapid habitats and in particular, their underwater movements and dive behaviour is required. Porpoises, which are the most abundant small cetacean at most European tidal sites, are difficult animals to tag, and the limited size of tidal habitats means that any telemetered animal would be likely to spend only a small proportion of time within them. Here, an alternative approach is explored, whereby passive acoustic monitoring (PAM) is used to obtain fine scale geo-referenced tracks of harbour porpoises in tidal rapid areas. Large aperture hydrophone arrays are required to obtain accurate locations of animals from PAM data and automated algorithms are necessary to process the large quantities of acoustic data collected on such systems during a typical survey. Methods to automate localisation, including a method to match porpoise detections on different hydrophones and separate different vocalising animals, and an assessment of the localisation accuracy of the large aperture hydrophone array are presented.
authors.affiliation: Sea Mammal Research Unit, Scottish Oceans Institute, Institiud Chuantan na h-Alba, University of St. Andrews, Gatty Marine Laboratory, East Sands, St. Andrews KY16 8LB, Scotland, United Kingdom.
authors.forename: Jamie
authors.initials: J
authors.lastname: Macaulay
authors.affiliation: Sea Mammal Research Unit, Scottish Oceans Institute, Institiud Chuantan na h-Alba, University of St. Andrews, Gatty Marine Laboratory, East Sands, St. Andrews KY16 8LB, Scotland, United Kingdom.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Gordon
authors.affiliation: Sea Mammal Research Unit, Scottish Oceans Institute, Institiud Chuantan na h-Alba, University of St. Andrews, Gatty Marine Laboratory, East Sands, St. Andrews KY16 8LB, Scotland, United Kingdom.
authors.forename: Douglas
authors.initials: D
authors.lastname: Gillespie
authors.affiliation: Sea Mammal Research Unit, Scottish Oceans Institute, Institiud Chuantan na h-Alba, University of St. Andrews, Gatty Marine Laboratory, East Sands, St. Andrews KY16 8LB, Scotland, United Kingdom.
authors.forename: Chloë
authors.initials: C
authors.lastname: Malinka
authors.affiliation: Sea Mammal Research Unit, Scottish Oceans Institute, Institiud Chuantan na h-Alba, University of St. Andrews, Gatty Marine Laboratory, East Sands, St. Andrews KY16 8LB, Scotland, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Northridge