Estimating minke whale ( Balaenoptera acutorostrata) boing sound density using passive acoustic sensors

• Published in: Marine Mammal Science
• Main Authors: Martin, Stephen W., Marques, Tiago A., Thomas, Len, Morrissey, Ronald P., Jarvis, Susan, DiMarzio, Nancy, Moretti, David, Mellinger, David K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2012
• Subjects: Balaenoptera acutorostrata; minke whale
• Online Access: http://dx.doi.org/10.1111/j.1748-7692.2011.00561.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1748-7692.2011.00561.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1748-7692.2011.00561.x

A bstract Density estimation for marine mammal species is performed primarily using visual distance sampling or capture‐recapture. Minke whales in Hawaiian waters are very difficult to sight; however, they produce a distinctive “boing” call, making them ideal candidates for passive acoustic density estimation. We used an array of 14 bottom‐mounted hydrophones, distributed over a 60 × 30 km area off Kauai, Hawaii, to estimate density during 12 d of recordings in early 2006. We converted the number of acoustic cues ( i.e. , boings) detected using signal processing software into a cue density by accounting for the false positive rate and probability of detection. The former was estimated by manual validation, the latter by applying spatially explicit capture‐recapture (SECR) methods to a subset of data where we had determined which hydrophones detected each call. Estimated boing density was 130 boings per hour per 10,000 km 2 (95% CI 104–163). Little is known about the population's acoustic behavior, so conversion from boing to animal density is difficult. As a demonstration of the method, we used a tentative boing rate of 6.04 boings per hour, from a single animal tracked in 2009, to give an estimate of 21.5 boing‐calling minke whales per 10,000 km 2 .