Cetacean acoustic occurrence on the <scp>US</scp> Atlantic Outer Continental Shelf from 2017 to 2020

Offshore wind energy is rapidly developing in US waters, with construction underway off Southern New England (SNE), an important region for many species, including the critically endangered North Atlantic right whale (NARW). A data-driven understanding of NARW upcalling behaviour is presented here to help establish proper monitoring protocols for mitigating impacts. Analyses of individual upcalls from 2 years of acoustic recordings showed that NARWs were detected at least 1 day every week throughout both years, with highest NARW presence from October to April. Weeks with more days of acoustic presence typically had more hours with calling activity, but the number of upcalls within a day or hour was variable, reflective of the social function of the upcall. Within SNE, on average, 95% of the time NARWs persisted for 10 days, and reoccurred again within 11 days. An evaluation of the time period over which it is most effective to monitor prior to commencing pile driving activities showed that with 1 h of pre-construction monitoring there was only 4% likelihood of hearing a NARW, compared to 74% at 18 h. Therefore, monitoring for at least 24 h prior to activity will increase the likelihood of detecting an up-calling NARW.

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Exploring and verifying the acoustic presence of southern right whales (Eubalaena australis) off Elephant Island, Antarctica

Wöhle,

Burkhardt,

van Opzeeland

et al. 2023

The Journal of the Acoustical Society of America

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Passive acoustic monitoring (PAM) can be used to monitor acoustic presence and behaviour of cetaceans, providing continuous, long-term, and seasonally unbiased data. The efficiency of PAM methods, however, depends on the ability to detect and correctly interpret acoustic signals. The upcall is the most prevalent vocalization of the southern right whale (Eubalaena australis) and is commonly used as a basis for PAM studies on this species. However, previous studies report difficulties to distinguish between southern right whale upcalls and similar humpback whale (Megaptera novaeangliae) vocalizations with certainty. Recently, vocalizations comparable to southern right whale upcalls were detected off Elephant Island, Antarctica. In this study, these vocalizations were structurally analyzed, and call characteristics were compared to (a) confirmed southern right whale vocalizations recorded off Argentina and (b) confirmed humpback whale vocalizations recorded in the Atlantic Sector of the Southern Ocean. Based on call features, detected upcalls off Elephant Island could be successfully attributed to southern right whales. Measurements describing slope and bandwidth were identified as the main differences in call characteristics between species. With the newly gained knowledge from this study, additional data can be analyzed providing further insight into temporal occurrence and migratory behaviour of southern right whales in Antarctic waters.

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Cetacean acoustic occurrence on the US Atlantic Outer Continental Shelf from 2017 to 2020

Cited by 9 publications

References 74 publications

Incorporating Particle Motion in Fish Communication and Listening Space Models

Incorporating Particle Motion in Fish Communication and Listening Space Models

Upcalling behaviour and patterns in North Atlantic right whales, implications for monitoring protocols during wind energy development

Exploring and verifying the acoustic presence of southern right whales (Eubalaena australis) off Elephant Island, Antarctica

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