Tina M. Yack

Description of sounds recorded from Longman's beaked whale, Indopacetus pacificus.

Sounds from Longmans beaked whale, Indopacetus pacificus, were recorded during shipboard surveys of cetaceans surrounding the Hawaiian Islands archipelago; this represents the first known recording of this species. Sounds included echolocation clicks and burst pulses. Echolocation clicks were grouped into three categories, a 15 kHz click (n = 106), a 25 kHz click (n = 136), and a 25 kHz pulse with a frequency-modulated upsweep (n = 70). The 15 and 25 kHz clicks were relatively short (181 and 144 ms, respectively); the longer 25 kHz upswept pulse was 288 ms. Burst pulses were long (0.5 s) click trains with approximately 240 clicks/s.

Baird's beaked whale echolocation signals

Echolocation signals from Bairds beaked whales were recorded during visual and acoustic shipboard surveys of cetaceans in the California Current ecosystem and with autonomous, long-term recorders in the Southern California Bight. The preliminary measurement of the visually validated Bairds beaked whale echolocation signals from towed array data were used as a basis for identifying Bairds signals in the autonomous recorder data. Two distinct signal types were found, one being a beaked whale-like frequency modulated (FM) pulse, the other being a dolphin-like broadband click. The median FM inter-pulse interval was 230 ms. Both signal types showed a consistent multi-peak structure in their spectra with peaks at ~9, 16, 25, and 40 kHz. Depending on signal type, as well as recording aspect and distance to the hydrophone, these peaks varied in relative amplitude. The description of Bairds echolocation signals will allow for studies of their distribution and abundance using towed array data without associated visual sightings and from autonomous seafloor hydrophones.

Passive acoustic monitoring using a towed hydrophone array results in identification of a previously unknown beaked whale habitat

Beaked whales are diverse and species rich taxa. They spend the vast majority of their time submerged, regularly diving to depths of hundreds to thousands of meters, typically occur in small groups, and behave inconspicuously at the surface. These factors make them extremely difficult to detect using standard visual survey methods. However, recent advancements in acoustic detection capabilities have made passive acoustic monitoring (PAM) a viable alternative. Beaked whales can be discriminated from other odontocetes by the unique characteristics of their echolocation clicks. In 2009 and 2010, PAM methods using towed hydrophone arrays were tested. These methods proved highly effective for real-time detection of beaked whales in the Southern California Bight (SCB) and were subsequently implemented in 2011 to successfully detect and track beaked whales during the ongoing Southern California Behavioral Response Study. The three year field effort has resulted in (1) the successful classification and tracking of Cuviers (Ziphius cavirostris), Bairds (Berardius bairdii), and unidentified Mesoplodon beaked whale species and (2) the identification of areas of previously unknown beaked whale habitat use. Identification of habitat use areas will contribute to a better understanding of the complex relationship between beaked whale distribution, occurrence, and preferred habitat characteristics on a relatively small spatial scale. These findings will also provide information that can be used to promote more effective management and conservation of beaked whales in the SCB, a heavily used Naval operation and training region.

Acoustic Ecology and Behavior of Minke Whales in the Hawaiian and Marianas Islands: Localization, Abundance Estimation, and Characterization of Minke Whale “Boings”

Balaenoptera acutorostrata (minke whale) is a small and elusive baleen whale that is rarely sighted in the tropical waters of the North Pacific Ocean. During winter and spring, complex sounds called ”boings” are frequently detected around the Hawaiian Islands and other Pacific island regions (Norris et al. 2009; Thompson and Friedl 1982). Although boings were described over 45 years ago (Wenz 1964), they were not attributed to minke whales until very recently (Rankin and Barlow 2005). Sightings of Balaenoptera acutorostrata are uncommon in tropical and subtropical waters; however, boings are frequently detected around the Hawaiian Islands using seafloor hydrophones and from hydrophone arrays towed from research vessels. Even today, very little is known about acoustic behaviors and ecology of Balaenoptera acutorostrata. The long-term objective of this research effort is to improve our understanding of the acoustic ecology and behavior of Balaenoptera acutorostrata in their breeding habitat.

Software for bioacoustic analysis of passive acoustic data.

Software analysis systems comprise an important stage in passive acoustic research. Here we compare and evaluate three animal acoustic analysis software systems: Ishmael, PAMGUARD, and XBAT. These packages are compared and evaluated for their capabilities at some of the common tasks in animal sound analysis: recording, display, detection, classification, measurement, localization, and tracking of animal sounds. They are also compared for their extensibility (how easy is it, say, to add a new detection algorithm), their ease of use (how hard is the software to learn to use, how quick to use it once one knows how), their hardware interfacing (what types of sound acquisition hardware can they receive sound from), their sound file interfaces (can they read everyone’s sound files), their documentation, and their software interfaces (how well do they share data with other programs, other methodologies, like visual surveys). Special features of each system will also be discussed.

Patterns of Occurrence and Marine Mammal Acoustic Behavior in Relation to Navy Sonar Activity Off Jacksonville, Florida

Passive acoustic data collected from marine autonomous recording units deployed off Jacksonville, FL (from 13 September to 8 October 2009 and 3 December 2009 to 8 January 2010), were analyzed for detection of cetaceans and Navy sonar. Cetaceans detected included Balaenoptera acutorostrata, Eubalaena glacialis, B. borealis, Physeter macrocephalus, blackfish, and delphinids. E. glacialis were detected at shallow and, somewhat unexpectedly, deep sites. P. macrocephalus were characterized by a strong diel pattern. B. acutorostrata showed the strongest relationship between sonar activity and vocal behavior. These results provide a preliminary assessment of cetacean occurrence off Jacksonville and new insights on vocal responses to sonar.

Integration of automated detection methods into NOAA Southwest Fisheries Science Center (SWFSC) acoustic marine mammal monitoring protocol.

Southwest Fisheries Science Center (SWFSC) has used combined visual and acoustic techniques to monitor marine mammal populations for the past 8 yrs. Currently, SWFSC passive acoustic surveys of cetaceans require specially trained personnel to monitor hydrophone signals in real‐time. While effective, this method is time‐consuming and costly. Automated detection of cetacean vocalizations would be a valuable tool during SWFSC surveys, allowing for detection when experienced technicians are unavailable. This technique is advantageous because it significantly reduces effort and removes sources of human error and bias in detection ability. PAMGUARD 1.0 CORE software was evaluated for use in automated detection of cetacean acoustic signals. Three different detector configurations of PAMGUARD were evaluated. This work shows that the majority of whistle and click events can be detected using PAMGUARD software. All of the PAMGUARD trials were capable of detecting whistles and clicks of cetacean species with varying...

Inter and intra specific variation in echolocation signals among odontocete species in Hawaii, the northwest Atlantic and the temperate Pacific

Odontocete species use echolocation signals (clicks) to forage and navigate. The aim of this study is to explore inter- and intra-specific variation in clicks among odontocete species in the Northwest Atlantic, Temperate Pacific, and Hawaii. Clicks were examined for seven species of delphinids in the Northwest Atlantic; common dolphin, Risso’s dolphin, pilot whale, rough-toothed dolphin, striped dolphin, Atlantic spotted dolphin, and bottlenose dolphin. Newly developed PAMGuard tools were used to automatically measure a suite of click parameters. Five parameters were compared among species; duration, center frequency, peak frequency, sweep rate, and number of zero crossings. Significant differences in duration, center and peak frequency were evident among species within this study area (Dunn’s test with Bonferroni adjustment p < 0.05). Geographic variation in click parameters among the three study regions was compared for five species; bottlenose dolphin, common dolphin, striped dolphin, pilot whale, and ...

Towing the line: Line-transect based density estimation of whales using towed hydrophone arrays

Towed hydrophone arrays have been used to monitor marine mammals from research vessels since the 1980s. Although towed hydrophone arrays have now become a standard part of line-transect surveys of cetaceans, density estimation exclusively using passive acoustic has only been attempted for a few species. We use examples from four acoustic line-transect surveys that we conducted in the North Pacific Ocean to illustrate the steps involved, and issues inherent, in using data from towed hydrophone arrays to estimate densities of cetaceans. We will focus on two species of cetaceans, sperm whales and minke whales, with examples of beaked whales and other species as needed. Issues related to survey design, data-collection, and data analysis and interpretation will be discussed using examples from these studies. We provide recommendations to improve the survey design, data-collection methods, and analyses. We also suggest areas where additional research and methodological development are required in order to produce robust density estimates from acoustic based data.Towed hydrophone arrays have been used to monitor marine mammals from research vessels since the 1980s. Although towed hydrophone arrays have now become a standard part of line-transect surveys of cetaceans, density estimation exclusively using passive acoustic has only been attempted for a few species. We use examples from four acoustic line-transect surveys that we conducted in the North Pacific Ocean to illustrate the steps involved, and issues inherent, in using data from towed hydrophone arrays to estimate densities of cetaceans. We will focus on two species of cetaceans, sperm whales and minke whales, with examples of beaked whales and other species as needed. Issues related to survey design, data-collection, and data analysis and interpretation will be discussed using examples from these studies. We provide recommendations to improve the survey design, data-collection methods, and analyses. We also suggest areas where additional research and methodological development are required in order to produ...

From clicks to counts: Applying line-transect methods to passive acoustic monitoring of sperm whales in the Gulf of Alaska

A visual and acoustic line-transect survey of marine mammals was conducted in the central Gulf of Alaska (GoA) during the summer of 2013. The survey area was divided into four sub-strata to reflect four distinct habitats; “inshore,” “slope,” “offshore,” and “seamount.” Passive acoustic monitoring was conducted using a towed-hydrophone array system. One of the main objectives of the acoustic survey was to obtain an acoustic-based density estimate for sperm whales. A total of 241 acoustic encounters of sperm whales during 6,304 km of effort were obtained compared to 19 visual encounters during 4,155 km of effort. Line-transect analytical methods were used to estimate the abundance of sperm whales. To estimate the detection function, target motion analysis was used to obtain perpendicular distances to individual sperm whales. An acoustic-based density and abundance estimate was obtained for each stratum (N = 78; CV = 0.36 offshore; N = 16; CV = 0.55 seamount; N = 121; and CV = 0.18 slope) and for the entire ...