@article {57571, title = {Acoustic crypsis in communication by North Atlantic right whale mother{\textendash}calf pairs on the calving grounds}, year = {2019}, abstract = {

Mammals with dependent young often rely on cryptic behaviour to avoid detection by potential predators. In the mysticetes, large baleen whales, young calves are known to be vulnerable to direct predation from both shark and orca predators; therefore, it is possible that mother\–calf pairs may show cryptic behaviours to avoid the attention of predators. Baleen whales primarily communicate through low-frequency acoustic signals, which can travel over long ranges. In this study, we explore the potential for acoustic crypsis, a form of cryptic behaviour to avoid predator detection, in North Atlantic right whale mother\–calf pairs. We predicted that mother\– calf pairs would either show reduced calling rates, reduced call amplitude or a combination of these behavioural modifications when compared with other demographic groups in the same habitat. Our results show that right whale mother\–calf pairs have a strong shift in repertoire usage, significantly reducing the number of higher amplitude, long-distance communication signals they produced when compared with juvenile and pregnant whales in the same habitat. These observations show that right whale mother\–calf pairs rely upon acoustic crypsis, potentially to minimize the risk of acoustic eavesdropping by predators.

}, keywords = {acoustic crypsis, baleen whale, eavesdropping, predator avoidance, right whale}, doi = {10.1098/rsbl.2019.0485}, url = {https://royalsocietypublishing.org/doi/10.1098/rsbl.2019.0485}, author = {Parks, Susan E. and Cusano, Dana A. and Sofie M. Van Parijs and Nowacek, Douglas P.} } @article {53254, title = {Implementing conservation measures for the North Atlantic right whale: considering the behavioral ontogeny of mother-calf pairs}, journal = {Animal Conservation}, year = {2018}, abstract = {

Understanding the behavioral ecology of a species is fundamental to effective conservation and management efforts. This study quantifies the behavioral ontogeny of North Atlantic right whale mother-calf pairs from birth to weaning spanning three critical habitat areas off the eastern coast of the United States and Canada. Data from 55 focal follows of 34 mother-calf pairs were collected from 2011 to 2015. Resting behaviors dominated the activity budgets for both mother and calf during the first 5 months, putting them at increased risk of vessel collisions. There was an increase in the proportion of active behaviors (travel, foraging, social activity) in both mother and calf as the calf matured. Importantly, the type of active behaviors, in particular surface skim feeding and surface active social behavior, meant that the risk of vessel collision to the pair did not decrease as the calf matured. Mother-calf right whale pairs showed very low calling rates on the calving grounds, suggesting that passive acoustic monitoring may not be an effective mitigation tool during the early months. However, calling rates increase once the pair leave the calving areas with both calf age and activity levels increasing, at which point passive acoustic monitoring becomes valuable. Protective measures need to take these rapid developmental changes throughout calf growth into account to improve the efficacy of protection measures for the endangered North Atlantic right whale and other species where behavioral ecology changes rapidly during maturation.

}, keywords = {activity budget, behavioral ontogeny, callrate, marine mammal, NorthAtlantic right whale, passive acoustic monitoring, vessel collision}, doi = {10.1111/acv.12457}, author = {D. A. Cusano and L. A. Conger and Sofie M. Van Parijs and S. E. Parks} } @article {52527, title = {Seen or heard? A comparison of visual and acoustic autonomous monitoring methods for investigating temporal variation in occurrence of southern right whales}, journal = {Marine Biology}, volume = {165}, year = {2018}, month = {Jan-01-2018}, abstract = {Passive acoustic detectors are widely used for monitoring distribution of cetaceans. Autonomous visual methods are less frequently employed; they are limited to detections during daylight and good weather, but offer potential advantages due to certainty of species{\textquoteright} identification and longevity of deployment. To compare performance of acoustic and visual methods, temporal changes in distribution of southern right whales, Eubalaena australis, were monitored in the remote sub-Antarctic Auckland Islands (50{\textdegree}31'S, 166{\textdegree}16'E). A time-lapse camera was deployed for 2 years from August 2010, taking an image every 70 min. The presence of whales was scored for each image taken during daylight (n = 8295). A passive acoustic recorder was deployed in August 2011, recording for 3.75 min every hour until battery life expired after 10 months. Each recording (n = 6978) was aurally reviewed. Both methods revealed a similar seasonal distribution; maximum detection rates were in the austral winter and no whales were detected in January or February. However, at the peak of right whale occurrence, the proportion of samples with whales detected was much higher for the acoustic recorder (93.9\% in August) than the time-lapse camera (14.8\%). A generalised additive model fitted to the visual data revealed significant effects of sea state and visibility. Acoustic detection rates were higher, probably because detection range is greater, and less affected by weather. The solar-powered time-lapse camera system, however, functioned effectively for much longer. We discuss the relative merits of visual and acoustic detectors and attempt to draw conclusions about their efficacy for different focal species and monitoring locations.}, issn = {0025-3162}, doi = {10.1007/s00227-017-3264-0}, url = {http://link.springer.com/10.1007/s00227-017-3264-0}, author = {Rayment, William and Webster, Trudi and Brough, Tom and Jowett, Tim and Dawson, Steve} } @article {47816, title = {Using nonlinear time warping to estimate North Pacific right whale calling depths in the Bering Sea}, journal = {The Journal of the Acoustical Society of America}, volume = {141}, year = {2017}, month = {Jan-05-2017}, pages = {3059 - 3069}, abstract = {

Calling depth distributions are estimated for two types of calls produced by critically endangered eastern North Pacific right whales (NPRWs) in the Bering Sea, using passive acoustic data collected with bottom-mounted hydrophone recorders. Nonlinear time resampling of 12 NPRW \“upcalls\” and 20 \“gunshots\” recorded in a critical NPRW habitat isolated individual normal mode arrivals from each call. The relative modal arrival times permitted range estimates between 1 and 40\ km, while the relative modal amplitudes permitted call depth estimates, provided that environmental inversions were obtained from high signal-to-noise ratio calls. Gunshot sounds were generally only produced at a few meters depth, while upcall depths clustered between 10 and 25\ m, consistent with previously published bioacoustic tagging results from North Atlantic right whales. A Wilcoxon rank sum test rejected the null hypothesis that the mean calling depths of the two call types were the same (p\ =\ 2.9\ \×\ 10\−5); the null hypothesis was still rejected if the sample set was restricted to one call per acoustic encounter (p\ =\ 0.02). Propagation modeling demonstrates that deeper depths enhance acoustic propagation and that source depth estimates impact both NPRW upcall source level and detection range estimates.

}, issn = {0001-4966}, doi = {10.1121/1.4982200}, url = {http://asa.scitation.org/doi/10.1121/1.4982200}, author = {Thode, Aaron and Bonnel, Julien and Thieury, Margaux and Fagan, Aileen and Verlinden, Chris and Wright, Dana and Crance, Jessica} } @article {47324, title = {Upcall production by southern right whale ( Eubalaena australis) mother-calf pairs may be independent of diel period in a nursery area}, journal = {Marine Mammal Science}, year = {2017}, month = {Jan-02-2017}, doi = {10.1111/mms.12382}, url = {http://doi.wiley.com/10.1111/mms.12382}, author = {Dombroski, Julia R. G. and Parks, Susan E. and Groch, Karina R. and Flores, Paulo A. C. and Sousa-lima, Renata S.} } @article {16462, title = {Two-stage detection of north Atlantic right whale upcalls using local binary patterns and machine learning algorithms}, journal = {Applied Acoustics}, volume = {120}, year = {2017}, month = {Jan-05-2017}, pages = {158 - 166}, abstract = {

In this paper, we investigate the effectiveness of two-stage classification strategies in detecting north Atlantic right whale upcalls. Time-frequency measurements of data from passive acoustic monitoring devices are evaluated as images. Vocalization spectrograms are preprocessed for noise reduction and tone removal. First stage of the algorithm eliminates non-upcalls by an energy detection algorithm. In the second stage, two sets of features are extracted from the remaining signals using contour-based and texture based methods. The former is based on extraction of time\–frequency features from upcall contours, and the latter employs a Local Binary Pattern operator to extract distinguishing texture features of the upcalls. Subsequently evaluation phase is carried out by using several classifiers to assess the effectiveness of both the contour-based and texture-based features for upcall detection. Comparing ROC curves of machine learning algorithms obtained from Cornell University\’s dataset reveals that LBP features improved performance accuracy up to 43\% over time\–frequency features. Classifiers such as the Linear Discriminant Analysis, Support Vector Machine, and TreeBagger achieve highest upcall detection rates with LBP features.

}, issn = {0003682X}, doi = {10.1016/j.apacoust.2017.01.025}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003682X17300774}, author = {Esfahanian, Mahdi and Erdol, Nurgun and Gerstein, Edmund and Zhuang, Hanqi} }