A Visual Sighting and Acoustic Detections of Minke Whales, Balaenoptera acutorostrata (Cetacea: Balaenopteridae), in Nearshore Hawaiian Waters

Abstract

Minke whales, Balaenoptera acutorostrata (Lacépède), have been considered a rare species in Hawaiian waters due to limited sightings during visual and aerial surveys. However, our research suggests that they are more common than previously considered. In spring 2005, a combined visual-acoustic survey of cetaceans in Hawaiian waters resulted in the sighting of a minke whale within 22 km of Kaua'i. Minke whale vocalizations were also detected at several other locations near Kaua'i and O'ahu. These 2005 reports are the first from nearshore (<50 km) Hawaiian waters despite years of previous shipboard and aerial surveys. The lack of historical sightings is likely due to misidentification or the inability to detect these animals during poor sighting conditions. We recommend that future cetacean surveys in Hawaiian waters include a passive acoustic component to increase the likelihood of detecting minke whales.

Minke whale acoustic behavior and multi-year seasonal and diel vocalization patterns in Massachusetts Bay, USA

“…However, visual detection of this species at sea can be difficult due to its small size and cryptic behavior (e.g. Rankin et al 2007). Alternative methods, such as PAM, offer a great opportunity to significantly improve studies of the ecology, behavior, distribution and abundance of this species (Oswald et al 2011).…”

Localization and tracking of phonating finless porpoises using towed stereo acoustic data-loggers

“…The mobile systems are often used in joint visual and acoustic surveys, to detect animals with increased levels in accuracy. Experimentally, in joint visual-acoustic surveys, mobile acoustic systems can usually detect one to ten times as many cetacean groups as visual ones ͑Barlow and Taylor, 2005; Rankin et al, 2007;Akamatsu et al, 2008͒. However, for comparison between visual and acoustic observations to determine detection performance of each method, determination of number of animals traveling together, distance, and bearing angle to the animal/group are necessary.…”

Widespread passive acoustic detection of Yangtze finless porpoise using miniature stereo acoustic data-loggers: A review

“…The instruments designed for the acoustic surveys and monitoring are varied, depending on a specific purpose and species of interest. Systems for mobile acoustic surveys often consist of cabled hydrophones and onboard multi-channel recording devices ͑Miller and Tyack, 1998; Gillespie and Chappell, 2002;Barlow and Taylor, 2005;Rankin et al, 2007͒, which are usually expensive and complicated to operate. Instruments designed for fixed acoustic monitoring often consists of one or two hydrophones and a battery-powered data-recording system that can provide continuous recordings of signals with a sampling rate up to 100 kHz ͑Scripps HARP, Wiggins and Hildebrand, 2007; HIMB/ PIFSC EAR, Lammers et al, 2008;Cornell Pop-Ups, Au and Hastings, 2008͒.…”

“…Passive acoustic surveys were often conducted during concurrent visual surveys. In joint visual-acoustic surveys, mobile towed acoustic systems usually detect several times more cetacean groups than visual techniques ͑Barlow and Taylor, 2005; Rankin et al, 2007͒. For the Yangtze finless porpoises that spend much of their time in the dark and turbid riverine water, sound are likely the primary means of acquiring environmental information. Acoustic behavior research based on both cabled hydrophone and tagging data loggers indicate that the porpoise, even in neonate individuals, produce high-frequency clicks frequently ͑Akamatsu et al., 1998, 2005cLi et al, 2005Li et al, , 2007.…”