TY - RPRT
TI - Testing and validation of automated whistle and click detectors using PAMGUARD 1.0
AU - Yack, T
AU - Barlow, J
AU - Rankin, S
AU - Gillespie, D
AB - Southwest Fisheries Science Center (SWFSC) has been using combined visual and acoustictechniques to monitor marine mammal populations for the past eight years. Passive acousticmonitoring was added to visual surveys in an effort to improve the accuracy of cetaceanpopulation size estimates and increase the understanding of cetacean vocal behavior (Rankin etal. 2008a-b). Acoustic detection methods are beneficial because they are not limited by mostweather conditions and are not restricted to daylight operations (Thomas et al., 1986). Theaddition of passive acoustic monitoring techniques to ship-based surveys can increase both therate and distance of marine mammal detections (Clark and Fritrup, 1997; Gordon et al., 2000;Barlow and Taylor, 2005). Passive acoustic methods are now an integral part of SWFSC’smarine mammal monitoring protocol.There are two main components to passive acoustic monitoring: detection and classification.Detection refers to the ability to recognize marine mammal signals, whereas classification refersto species-specific acoustic identification of those signals. Marine mammal detection requiresknowledge of marine mammal vocal behavior. Delphinid vocalizations are typically classifiedinto three categories: whistles, echolocation clicks, and burst pulse signals. Whistles arecontinuous, narrow band, frequency-modulated signals. They can be pure tone or containharmonics of the fundamental frequency. Whistles are believed to function as social signals(Janik and Slater 1998, Herzing 2000, Lammers et al. 2003) and range in duration from fractionsof a second to several seconds. They typically range in fundamental frequency from 2 to 30kHz, depending on the species (Lammers et al., 2003; Oswald et al., 2004). Echolocation clicksare impulsive, broadband signals that typically vary in peak frequency between 10 and over 100kHz (Norris and Evans 1966; Au, 1980). These signals are used primarily for navigation and inobject discrimination (Au, 1993). Burst pulse signals are composed of short-interval broadbandclick trains, resulting in a signal that may appear tonal due to the high repetition rate of the clicks(Watkins, 1967; Herzing, 2000). Burst pulse sounds may be used as social signals as well as forecholocation tasks (Dawson, 1991). These three categories of call types are not mutuallyexclusive, as transitions from increasing click rates to click bursts to purely tonal signals canoccur during acoustic encounters (Murray et al., 1998).Currently, SWFSC passive acoustic surveys of cetaceans require specially trained personnel tocontinually monitor the hydrophone array signals in real-time in order to detect cetaceanvocalizations and plot bearings to the source. While effective, this method is time consumingand costly. Automated detection of cetacean vocalizations would be a valuable tool duringmarine mammal surveys, allowing for detection when experienced technicians are unavailable.This technique is advantageous not only because it significantly reduces human effort, but alsobecause it removes sources of human error and bias in detection ability. Results from a recentSWFSC study, show that acoustic detection capability varies by group size, species, and acousticbehavior (Rankin et al., 2008b). These findings emphasize the need for comprehensive study ofspecies-specific vocal behavior. Reliable automated detectors could provide valuableinformation about vocal behavior, species specific acoustic detectability, and vocalization ratesfor several cetacean species. This is an important step in the effort to utilize acoustic line-transect data to estimate population sizes for cetacean species.The goal of this study was to evaluate the performance and utility of PAMGUARD 1.0 Core software for use in automated detection of marine mammal acoustic signals. Three differentdetector configurations of PAMGUARD are compared. These automated detection algorithmsare evaluated by comparing them to the results of manual detections made by an experiencedbio-acoustician (author TMY). Ultimately, it is our goal to integrate automated detection andlocalization methods into SWFSC’s acoustic marine mammal monitoring protocol and this workis an important step in doing so.
DA - 2009/05//
PY - 2009
SP - 62
PB - National Oceanic and Atmospheric Administration (NOAA)
SN - NOAA-TM-NMFS-SWFSC-443
UR - https://repository.library.noaa.gov/view/noaa/3665
LA - English
KW - Wind Energy
KW - Fixed Offshore Wind
KW - Floating Offshore Wind
KW - Avoidance
KW - Displacement
KW - Habitat Change
KW - Noise
KW - Marine Mammals
ER -