Blue whale continuous frequentations of St. Lawrence habitats from multi-year PAM series / Yvan Simard ... [et al.]. : Fs70-5/2016-091E-PDF

"The endangered northwest Atlantic blue whale is a regular visitor of the Gulf of St. Lawrence where they feed upon aggregated krill. As part of the population recovery plan, a passive acoustic monitoring (PAM) observatory was set up to track the space-time patterns of blue whale use of this northwest Atlantic marginal sea from their species-specific calls from 2010 to 2015. The PAM network included 4 regular multi-year stations and 2 1-year stations covering the two Gulf entrances and the expected excursion routes. The most frequent “A-type” infrasonic call was tracked with a dedicated algorithm while the rarer and less energetic low frequency D-call was manually detected from the spectrograms, aided by an energy detector. During the monitoring period, the blue whale was present year-round in the southern Gulf of St. Lawrence, and almost year-round in the Lower Estuary. They were not detected at the northeastern station near Belle Isle Strait. No clear lag between the appearance and disappearance at the stations along the inland route from the Atlantic was observed, which does not plea in favour of a seasonal synchronous migration. The co-occurrence of detections at all sites during a large part of the annual cycle indicate a dispersed population over numerous sites of interest in the studied area, which includes periods of arrival and departures as indicated by fluctuations in call occurrence. Results clearly show that blue whales occupy the whole region, not only during summer and fall, but year-round“--Abstract, p. iv.

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