Passive acoustic monitoring predicts daily variation in North Atlantic right whale presence and relative abundance in Roseway Basin, Canada

Abstract

North Atlantic right whale monitoring in Roseway Basin, Canada, is primarily based on short‐term (<14 d) visual surveys conducted during August–September. Variability in survey effort has been the biggest limiting factor to studying changes in the population's occurrence and habitat use. Such efforts could be enhanced considerably using passive acoustic monitoring (PAM). We sought to determine if variation in whale presence, relative abundance, demography, and/or behavior (estimated through visual surveys) could be explained by variation in three right whale call types in this habitat. A generalized linear model was fit to 23 d of concurrent PAM and visual monitoring during four summers within the Roseway Basin Right Whale Critical Habitat boundaries. The model revealed significant positive relationships between relative abundance, call counts and presence of surface‐active group behavior. PAM can refine daily right whale presence estimates. While visual observations (n = 23 d) implied a 40% decline in right whale presence during 2014–2015 relative to 2004–2005, PAM data (n = 211 d) showed right whales were present between 71%–85% of survey days throughout all years analyzed. We demonstrate that PAM is a useful tool to extend periods of right whale monitoring, especially in areas where visual monitoring efforts may be limited.

Using sonobuoys and visual surveys to characterize North Atlantic right whale (Eubalaena glacialis) calling behavior in the Gulf of St. Lawrence

“…As we have shown, right whale calling is ephemeral, highly variable, and dependent on behavioral state rather than the number of observed individuals. Our results align with those of Clark et al (2010) but contrast with findings from Matthews et al (2001) and Durette-Morin et al (2019), both of which reported a statistically significant predictive relationship between the numbers of calls and the numbers of whales observed. The discrepancy may be attributed to the aggregation sizes considered, where 89% (33 of 37) of our observations were associated with observations with more than 10 whales compared to 14% (3 of 12) and 22% (5 of 23) from Matthews et al (2001) and Durette-Morin et al (2019), respectively.…”

“…Furthermore, Durette-Morin et al ( 2019) used fixed moorings that monitor constantly (24 h d −1 , as opposed to 0.5 to 6 h d −1 when weather is good) regardless of the number of whales present. Our study also occurred in a different habitat and time of year from the previously mentioned papers, as Clark et al (2010) studied Cape Cod Bay from January to May, Durette-Morin et al (2019) studied Roseway Basin from August to September, and Matthews et al (2001) studied the Great South Channel and Cape Cod from April to May and the Bay of Fundy from August to September. Thus, habitat and time of year may affect whale behavior and contribute to the observed differences among these studies.…”

“…The aggregations Clark et al (2010) observed were mostly groups of 2 or 3 whales. Another reason for the discrepancy may be that Matthews et al (2001) and Durette-Morin et al (2019) used vessels as visual survey platforms, which may not have been as effective as an aircraft at collecting observations at the spatial scale of acoustic monitoring. Furthermore, Durette-Morin et al ( 2019) used fixed moorings that monitor constantly (24 h d −1 , as opposed to 0.5 to 6 h d −1 when weather is good) regardless of the number of whales present.…”

“…Numerous studies have demonstrated that PAM can provide a reliable indication of right whale presence (e.g. Clark et al 2010, Durette-Morin et al 2019) and have used this information to make inferences about right whale distribution over large temporal and spatial scales (e.g. Davis et al 2017, Durette-Morin 2021.…”

Make the CPUs do the hard work - Automated acoustic feature extraction and visualization for marine ecoacoustics applications illustrated using marine mammal Passive Acoustic Monitoring datasets

“…One of PAM's most common applications is in marine mammal monitoring and conservation. Marine mammals produce complex vocalizations that are species-specific (if not individually unique), and such vocalizations can be used when estimating species' distributions and habitat use (Durette-Morin et al, 2019;Kowarski & Moors-Murphy, 2020). PAM applications in marine mammal research span from the study of their vocalizations and behaviours (Madhusudhana et al, 2019;Vester et al, 2017) to assessing anthropogenic disturbance (Nguyen Hong Duc et al, 2021).…”