title: Effects of different analysis techniques and recording duty cycles on passive acoustic monitoring of killer whales.
abstract: Killer whales in British Columbia are at risk, and little is known about their winter distribution. Passive acoustic monitoring of their year-round habitat is a valuable supplemental method to traditional visual and photographic surveys. However, long-term acoustic studies of odontocetes have some limitations, including the generation of large amounts of data that require highly time-consuming processing. There is a need to develop tools and protocols to maximize the efficiency of such studies. Here, two types of analysis, real-time and long term spectral averages, were compared to assess their performance at detecting killer whale calls in long-term acoustic recordings. In addition, two different duty cycles, 1/3 and 2/3, were tested. Both the use of long term spectral averages and a lower duty cycle resulted in a decrease in call detection and positive pod identification, leading to underestimations of the amount of time the whales were present. The impact of these limitations should be considered in future killer whale acoustic surveys. A compromise between a lower resolution data processing method and a higher duty cycle is suggested for maximum methodological efficiency.
authors: University of Victoria, School of Earth and Ocean Sciences, Bob Wright Centre A405, 3800 Finnerty Road, Victoria, British Columbia, V8P 5C2, Canada. ariera@uvic.ca
authors: Amalis
authors: A
authors: Riera
authors: John K
authors: JK
authors: Ford
authors: N
authors: N
authors: Ross Chapman
mesh_terms: D000162:Acoustics; D000818:Animals; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D008386:Marine Biology / Q000379:methods*; D009716:Numerical Analysis, Computer-Assisted; D009792:Oceans and Seas; D011156:Population Density; D012621:Seasons; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013997:Time Factors; D014828:Vocalization, Animal; D050685:Whale, Killer / Q000502:physiology* / Q000523:psychology