title: Passive acoustic monitoring of coastally associated Hawaiian spinner dolphins, Stenella longirostris, ground-truthed through visual surveys.
abstract: Effective decision making to protect coastally associated dolphins relies on monitoring the presence of animals in areas that are critical to their survival. Hawaiian spinner dolphins forage at night and rest during the day in shallow bays. Due to their predictable presence, they are targeted by dolphin-tourism. In this study, comparisons of presence were made between passive acoustic monitoring (PAM) and vessel-based visual surveys in Hawaiian spinner dolphin resting bays. DSG-Ocean passive acoustic recording devices were deployed in four bays along the Kona Coast of Hawai'i Island between January 8, 2011 and August 30, 2012. The devices sampled at 80 kHz, making 30-s recordings every four minutes. Overall, dolphins were acoustically detected on 37.1% to 89.6% of recording days depending on the bay. Vessel-based visual surveys overlapped with the PAM surveys on 202 days across the four bays. No significant differences were found between visual and acoustic detections suggesting acoustic surveys can be used as a proxy for visual surveys. Given the need to monitor dolphin presence across sites, PAM is the most suitable and efficient tool for monitoring long-term presence/absence. Concomitant photo-identification surveys are necessary to address changes in abundance over time.
authors.affiliation: Division of Marine Science and Conservation, Nicholas School of the Environment, Duke, University Marine Laboratory, 135 Duke Marine Lab Road, Beaufort, North Carolina 28516, USA.
authors.forename: Heather L
authors.initials: HL
authors.lastname: Heenehan
authors.affiliation: Murdoch University Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia.
authors.forename: Julian A
authors.initials: JA
authors.lastname: Tyne
authors.affiliation: Murdoch University Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia.
authors.forename: Lars
authors.initials: L
authors.lastname: Bejder
authors.affiliation: Passive Acoustic Research Group, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, Massachusetts 02543, USA.
authors.forename: Sofie M
authors.initials: SM
authors.lastname: Van Parijs
authors.affiliation: Division of Marine Science and Conservation, Nicholas School of the Environment, Duke, University Marine Laboratory, 135 Duke Marine Lab Road, Beaufort, North Carolina 28516, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Johnston
mesh_terms: D000162:Acoustics; D000818:Animals; D001070:Appetitive Behavior; D006254:Hawaii; D011159:Population Surveillance / Q000379:methods; D012146:Rest; D050706:Stenella