Humpback whale songs have been described worldwide and studies exploring non-song vocal behavior continue to expand; however, studies on the transition periods when whales shift to and from the seasonal behavioral state of singing are lacking and may be potentially informative regarding the proximal factors controlling the onset and offset of humpback whale male singing. Acoustic recorders collected data off eastern Canada continuously from the Bay of Fundy in the fall of 2015 and near-continuously off northeast Nova Scotia in the spring of 2016. Humpback whale acoustic occurrence and behavior were identified by systematically reviewing a subset of acoustic recordings for presence before analyzing the highest quality recordings for behavior. The onset of singing in the fall was gradual over a period of about three weeks with an intermediate form, termed “song fragment,” occurring prior to full songs. In comparison, singing in the spring seemed to end abruptly with few song fragments. Song fragments could be produced by juveniles learning to sing for the first time or mature males preparing for breeding activities prior to migrating to southern breeding grounds. The authors propose an alternative hypothesis that the timing and manner of transitions could be driven by physiological processes similar to those documented in songbirds.

In 2017, an endangered North Atlantic right whale mortality event in the Gulf of St. Lawrence, Canada, triggered the implementation of dynamic mitigation measures that required real-time information on whale distribution. Underwater glider-based acoustic monitoring offers a possible solution for collecting near real-time information but has many practical challenges including self-noise, energy restrictions, and computing capacity, as well as limited glider-to-shore data transfer bandwidth. This paper describes the development of a near real-time baleen whale acoustic monitoring glider system and its evaluation in the Gulf of St. Lawrence in 2018. Development focused on identifying and prioritizing important acoustic events and on sending contextual information to shore for human validation. The system performance was evaluated post-retrieval, then the trial was simulated using optimized parameters. Trial simulation evaluation revealed that the validated detections of right, fin, and blue whales produced by the system were all correct; the proportion of species occurrence missed varied depending on the timeframe considered. Glider-based near real-time monitoring can be an effective and reliable technique to inform dynamic mitigation strategies for species such as the North Atlantic right whale.

The location of reproduction is a key life history trait, as it influences the bio-physical conditions that offspring experience and, thus, fitness. Capelin Mallotus villosus is a small (< 200 mm), short-lived forage fish that spawns in two habitats in coastal Newfoundland: warm beaches and cool, deep water (15–40 m). From 2009 to 2014, we investigated temperature-dependent spawning habitat use by quantifying hourly temperature at spawning sites during July within each habitat along with population-level spawning site use. Capelin did not spawn at sites with temperatures <2 °C or consistently >12 °C, supporting the estimated suitable spawning temperature range (2–12 °C). Spawning typically occurred exclusively at beaches early in July when deep-water habitat was too cold (i.e. <2 °C), and then switched to deep-water habitat later in July when beaches became too warm (i.e. >12 °C). Spawning overlapped for 1–3 d in both habitats when temperatures were within suitable ranges (2011, 2013), but capelin also spawned exclusively in one habitat when temperatures remained suitable in the other. The latter suggests that other factors influence spawning habitat selection, such as conspecific egg densities and other environmental conditions. Overall, the flexible use of spawning habitats, along with wide tolerance ranges of capelin eggs to environmental conditions, are likely key adaptations to maximize fitness and stabilize population dynamics of this important forage fish species in an unpredictable environment.

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Vessel-related noise is a potential stressor for coral reef fauna. The Parque Nacional Arrecifes de Cozumel (PNAC) is a Mexican Marine Protected Area that is exposed to pervasive vessel traffic. PNAC is also the primary range of splendid toadfish (Sanopus splendidus, family Batrachoididae), an IUCN redlisted soniferous fish for which vessel noise may represent a threat. We conducted a passive acoustic monitoring survey during summer of 2017 at Paraiso Reef in PNAC and obtained the first scientific recordings from splendid toadfish, enabling a vocal characterization of the species. We simultaneously collected data on sound levels of vessels passing near the reef. High noise levels of cruise ship and small motorboat traffic caused elevated anthropogenic sound pressure levels for up to 15 hr per day in the same bandwidth as toadfish vocalizations. A single cruise ship added up to 4 dB above nighttime ambient levels while small motorboat traffic added up to 7 dB. The overlap of toadfish vocalizations and vessel-related noise highlights the susceptibility of splendid toadfish to acoustic masking and reduction in communication space throughout the day, warranting further study. Because acoustic communication is critical to toadfish reproductive success, noise from cruise ships and small motorboats may threaten splendid toadfish individuals or population viability. K E Y W O R D Sacoustic masking, coral reef, passive acoustic monitoring, soundscape, toadfishCozumel, Mexico has been a popular tourist destination for several decades, with diving, recreational fishing, and cruise travel comprising most of the island's economy. Continued tourism to Cozumel is dependent on a healthy and biologically diverse reef ecosystem. However, reefs worldwide, including those in Cozumel, are experiencing declines in condition and function from cumulative stressors including coral disease, overfishing, tourism, marine pollution, sedimentation, and climate change (