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Six species of cetaceans have been found to occur in the Chukchi Sea adjacent to the Pacific walrus rookery at Cape Vankarem: the gray whale, the bowhead whale, the humpback whale, the killer whale, the beluga whale, and the fin whale. The humpback whale is noted to have become abundant in the Chukchi Sea in the summer in recent years. The coastal mortality of cetaceans in a 100-km section in the western part of the distribution range of both gray and bowhead whales has been established to average 1.66 and 0.3 whales per year, respectively. Mostly young animals of 1–2 years of age appear to die, the main cause of death of which is predation by killer whales. The most common whales in that area in the summer–autumn period are humpback whales, which at the same time form significant concentrations in the coastal waters during the accumulation of the main food items. Both bowhead and gray whales are much less frequent, found rather irregularly, while despite the relative scarcity of encounters, these species account for the lion's share of all dead cetaceans. [ABSTRACT FROM AUTHOR]

Darrieus vertical axis wind turbines are an omnidirectional type of turbine. The major concern with this type of turbine is its low efficiency. The experimental study focuses on implementing a bioinspired design. Humpback Whale flippers are mimicked for a novel design of a swept curved blade with leading-edge tubercles. A NACA4412 thin cambered profile and NACA0022 thick symmetric airfoil profile are chosen for making turbine blades, and the study is performed in the subsonic wind tunnel at Reynolds numbers ranging from 15,000 to 70,000. To validate the accuracy and novelty of the model over the conventional model, performance parameters like torque and power coefficients are calculated to showcase valid improvement in performance. It is exciting to observe that curved blades with tubercle leading edge modification have shown better results. Among seven configurations of turbine blades, the model with a high amplitude to wavelength A/ γ ratio showed more promising results than the other configurations regarding efficiency. A maximum of 35% C P was obtained with the novel curved tubercle model with A/ γ = 0.5, significantly enhancing electrical output. [ABSTRACT FROM AUTHOR]

This study investigated the presence of ectoparasites in stranded cetaceans along the coast of Sergipe, Brazil. The parasitological material, dates and informations about the hosts was obtained from a biological collection. Were analysed four Megaptera novaeangliae, one of Sotalia guianensis, and one of Peponocephala electra. A total of 264 ectoparasites were collected from these carcasses – 263 amphipods of the species Cyamus boopis and Syncyamus ilheusensis, and a single cymothoid isopod, identified as Livoneca redmanii. C. boopis showed a average intensity of 77.0 parasites per host, and a prevalence of 100% in the analysed humpback whale carcasses, representing the first record of this louse species on humpback whales in the region. S. ilheusensis appears to have a rare occurrence and specificity to the host P. electra, being its third report in the scientific literature. Additionally, the discovery of the isopod L. redmanii on Sotalia guianensis is unprecedented, being the first report of an isopod parasitizing this cetacean and expanding our knowledge about the host flexibility of this ectoparasite. The attachment of the isopod to the dolphin's skin was likely favored by the absence of mucus, as found in fish. These findings provide new insights into the ecology of these ectoparasites. [ABSTRACT FROM AUTHOR]

In coastal British Columbia, Canada, marine megafauna such as humpback whales (Megaptera novaeangliae) and fin whales (Balaenoptera physalus velifera) have been subject to a history of exploitation and near extirpation. While their populations have been in recovery, significant threats are posed to these vulnerable species by proposed natural resource ventures in this region, in addition to the compounding effects of anthropogenic climate change. Genetic tools play a vital role in informing conservation efforts, but the associated collection of tissue biopsy samples can be challenging for the investigators and disruptive to the ongoing behaviour of the targeted whales. Here, we evaluate a minimally intrusive approach based on collecting exhaled breath condensate, or respiratory 'blow' samples, from baleen whales using an unoccupied aerial system (UAS), within Gitga'at First Nation territory for conservation genetics. Minimal behavioural responses to the sampling technique were observed, with no response detected 87% of the time (of 112 UAS deployments). DNA from whale blow (n = 88 samples) was extracted, and DNA profiles consisting of 10 nuclear microsatellite loci, sex identification and mitochondrial (mt) DNA haplotypes were constructed. An average of 7.5 microsatellite loci per individual were successfully genotyped. The success rates for mtDNA and sex assignment were 80% and 89% respectively. Thus, this minimally intrusive sampling method can be used to describe genetic diversity and generate genetic profiles for individual identification. The results of this research demonstrate the potential of UAS‐collected whale blow for conservation genetics from a remote location. see also the Perspective by Elena Valsecchi. [ABSTRACT FROM AUTHOR]

The sequencing of a kidney sample (KW2013002) from a stranded Megaptera novaeangliae (Humpback whale) calf is the first chromosome-level reference genome for this species1. The calf, a 457 cm and 2,500 lbs male, was found stranded in Hawai'i Kai, HI, in 2013 and was marked as abandoned/orphaned. In 2023, 1 g of kidney was sequenced with PacBio long-read DNA sequencing, chromatin conformation capture (Hi-C), RNA sequencing, and mitochondrial sequencing to comprehensively characterize the genome and transcriptome of M. novaeangliae. Data validation includes a synteny analysis, mitochondrial annotation, and a comparison of BUSCO scores (scaffold v. reference genome and Balaenoptera musculus (Blue whale) v. M. novaeangliae). BUSCO analysis was performed on an M. novaeangliae scaffold-level assembly to determine genomic completeness of the reference genome, with a scaffold BUSCO score of 91.2% versus a score of 95.4%. Synteny analysis was performed using the B. musculus genome as comparison to determine chromosome-level coverage and structure. Further, a time-based phylogenetic tree was constructed using the sequenced data and publicly available genomes. [ABSTRACT FROM AUTHOR]

Background: Studying movement patterns of individual animals over time can give insight into how they interact with the environment and optimize foraging strategies. Humpback whales (Megaptera novaeangliae) undertake long seasonal migrations between feeding areas in polar regions and breeding grounds in tropical areas. During the last decade, several individuals have had up to a 3-month stop-over period around specific fjord-areas in Northern Norway to feed on Norwegian spring-spawning (NSS-) herring (Culpea harengus L.). Their behavioral patterns during this period are not well understood, including why some whales seemingly leave the fjords and then later return within the same season. Methods: To investigate whale behavior during this seasonal stopover, we classified humpback whale tracks into five distinct movement modes; ranging, encamped, nomadic, roundtrip and semi-roundtrip. A behavioral change point analysis (BCPA) was used to select homogeneous segments based on persistence velocity. Then, net squared displacement (NSD) over time was modeled to differentiate movement modes. This study also manually identified longer roundtrips away from the fjords that lasted several days and examined movement modes within these. Results: Inside the fjord systems, encamped mode was most prevalent in December–January, suggesting the whales were mainly foraging on overwintering NSS-herring in this area. During the same winter seasons, half of the whales left the fjords and then returned. We hypothesize that these trips serve as 'searching trips' during which the whales seek better feeding opportunities outside the fjords. If better foraging conditions are not found, they return to the fjords to continue their feeding. The overall most common mode was ranging (54%), particularly seen during the start of their southwards migration and in areas outside the fjord systems, indicating that the whales mainly moved over larger distances in the offshore habitat. Conclusions: This study serves as a baseline for future studies investigating both the searching trip theory and humpback whale behavior in general, and confirms that this method could be useful to analyze local scale movement patterns of satellite tagged whales. [ABSTRACT FROM AUTHOR]

Renowned marine mammal scientist Roger Payne, who passed away in 2023 at the age of 88, is best known for his work on humpback whale songs, which helped change public perception of whales. His research on live whales at sea and his recordings of humpback songs played a significant role in the environmental conservation movement of the early 1970s. Payne's contributions extended beyond whales, as he conducted groundbreaking research on other species and was known for his ability to merge science, art, and music. The text also highlights the experiences and mentorship of Roger and Katy Payne, emphasizing their generosity, wisdom, and dedication to conservation. The authors express gratitude for the opportunities and knowledge gained through their association with the Paynes. [Extracted from the article]

Understanding animals' movements is essential to assess habitat use, life‐history strategies, and population dynamics. Here, we investigate the movement and behavior patterns of 153 humpback whales in the Southwest Atlantic Ocean (SWA) using data obtained by satellite telemetry between 2003 and 2019 during the species' breeding season (August–December) off the Brazilian coast. Switching state space models were applied to estimate behavior states (bmode) classified as Area Restricted Search (ARS), Transiting (TRANS), or uncertain. Whales were distributed from 4°S to 24°S, and five clusters of ARS behavior were identified along the Brazilian coast. Generalized linear mixed modeling revealed three main results: (1) a transition towards more sinuous behavioral states with increasing latitude; (2) more sinuous movement behavior around new moons; (3) movement behavior was temporally dynamic throughout the breeding season over the years, particularly in 2019. The results then revealed important regions where humpback whales cluster to engage in mating and nursing behaviors, highlighting the influence of spatial location and environmental cycles on their behavior. Estimated movement behavior presented here improves the knowledge about the habitat use and movement patterns of SWA humpback whales in their breeding ground and can be used to mitigate potential human‐related impacts. [ABSTRACT FROM AUTHOR]

After the worldwide moratorium on whaling, humpback whale populations began to recover, reoccupying former areas of use, as also observed on the Brazilian coast. Abrolhos Bank represents the area of greatest humpback whale concentration but the number of individuals to the north has increased, as has happened in the region of Serra Grande. To compare relative abundance, habitat use, and movement patterns between a well‐established breeding and a reoccupation area, visual monitoring from land‐based stations was performed: 160 days in the Abrolhos Archipelago located on the Abrolhos Bank and 133 days in Serra Grande in 2014, 2015, 2018, and 2019. While relative abundance varied annually in the Abrolhos Archipelago, it gradually increased in Serra Grande, surpassing the number registered in Abrolhos in 2019. Group composition frequency was similar between areas except for mother and calf accompanied by one or more escorts, which were more frequent in Abrolhos. Despite similar movement speed and linearity values, whales in Serra Grande had a higher reorientation rate. Monitoring different areas occupied by this population supports decisions about spatial management of the Brazilian coast in relation to the implementation of anthropogenic activities, especially in areas where whales have recently returned to occupy. [ABSTRACT FROM AUTHOR]

Humpback whale (Megaptera novaeangliae) nonsong vocalizations, or social calls, are much more poorly understood than humpback song. We examined humpback whale social calls from a foraging ground in southern British Columbia (BC) and developed a catalog for humpback social calls in BC. We tagged four humpback whales on the eastern edge of Swiftsure Bank, BC, in early September 2020, with a passive acoustic and movement tag. We manually classified 32 call types in our data set based on comparisons with published classifications of humpback social calls. Many of the calls identified in our data set had similar characteristics to calls from other locations. We also used two statistical classification methods, a cluster analysis and a random forest. The cluster analysis grouped 20 of these call types into four categories, and the random forest classifier was able to accurately classify all 20 call types 87.6% of the time. This study fills a geographical gap of humpback whale social calls on foraging grounds and is a first step towards categorizing the social calls of humpback whales in BC. [ABSTRACT FROM AUTHOR]

The global conservation of humpback whales Megaptera novaeangliae relies on continuous assessments of the populations' post-whaling status, which in turn require information on population mixing and movements. One of the seven breeding stocks in the Southern Hemisphere, breeding stock C and its associated four substocks (C1–C4), utilises the western Indian Ocean in several discrete breeding grounds. However, information on the mixing of stocks across breeding grounds is limited. This study utilises photo-identification methods applied to the first multi-regional catalogue of fluke images available for substock C1S (the southern component of substock C1) which uses the southern portion of the breeding ground, developed as part of this study, to investigate the whales' movements along the southeastern coast of southern Africa. The identification of 1 746 unique individuals, including 11 withinyear matches and 48 between-year matches of 45 individuals, provides new insight into the intra-regional migration patterns, fidelity and structure of substock C1S. The within-year match results confirmed that individual humpback whales are broadly seasonally present for extended periods and visit multiple subregions along this coast, while the between-year matches revealed long-term fidelity to this coastline. Moreover, five of the between-year matches between subregions in South Africa and Mozambique linked the South African migration corridor to the breeding ground in southern and central Mozambique. These findings provide valuable insights into the movement patterns of substock C1S and significantly address the challenges of effective population management, which includes difficulties associated with the whale-watching industry on the east coast of South Africa. [ABSTRACT FROM AUTHOR]

Ocean noise produced by seismic exploration has been implicated in causing changes in baleen whale hearing, physiology, feeding, breeding, and migratory behaviours. Here, we observed changes in the mating tactics of humpback whales (Megaptera novaeangliae) during a one-hour exposure to nearby seismic air guns. Males employ a conditional mating strategy where they switch between singing and non-singing tactics. Singing is presumably an advertisement signal, while non-singing behaviours include seeking out and joining with females as well as forming competitive groups. During periods of active air guns, the number of male singing whales increased, and singers were more likely to be observed joining females. Conversely, non-singing males were less likely to engage in joining interactions suggesting that active air guns caused a switch in male breeding tactics. Though we cannot translate these effects into changes in breeding success, this indicates that seismic exploration has the potential to alter breeding behaviours in baleen whales. Male humpback whales respond to seismic air gun activity by increasing singing and breeding activity. [ABSTRACT FROM AUTHOR]

Humpback whales (Megaptera novaeangliae) use southern British Columbia waters to feed, but the type and quantity of prey in many areas used for feeding is unknown. We conducted active acoustic prey mapping in 55 small grid-surveys in two regions off Vancouver Island. We quantitatively compared fish and zooplankton-dominated biomass in known feeding areas with and without foraging humpback whales, and qualitatively described the prey characteristics of the foraged areas. Surveys of the water column suggest that, on average, humpback whale foraging was associated more with increased zooplankton than fish biomass. Prey characteristics varied between the two regions (∼500 km apart), but there was no significant difference in mean backscatter strength in the actively foraged areas between the two regions. Frequency differencing discriminated between the dominant taxa in the water column, but potential epipelagic prey (<10 m) would have been omitted from analysis. However, average depth at the maximum acoustic prey detections was significantly deeper when whales were present (84 m) versus absent (60 m), suggesting predominantly subsurface foraging opportunities suitable to prey mapping. [ABSTRACT FROM AUTHOR]

Cavitation and induced noise are common issues in the operation of mixed-flow pumps, affecting their stability. Studying these phenomena is of both academic and engineering interest. Previous research has mainly focused on modifying the impeller blade profile or optimizing the pump structure to reduce cavitation and noise. In this paper, we apply a bionic design to the mixed-flow pump impeller by mimicking the natural shape of a humpback whale's pectoral fin on the leading edge of the blade. We compare the cavitation suppression and noise reduction effects of this design with those of a conventional mixed-flow pump. Unsteady flow calculations for the original pump at different flow rates revealed that at its rated speed, increasing flow rates led to lower pressure in the low-pressure region on the suction surface of the impeller, expanding the cavitation-prone area. By applying the bionic design, we studied the unsteady cavitation flow and its induced noise. Results showed that the impeller and guide vane experienced larger pressure pulsations at the rotation frequency and its multiples. The bionic modification increased the cavitation initiation speed and reduced the cavity volume within the runner. With an NPSH (net positive suction head) of 6.76, the void volume in the bionic pump was only 79% of that in the original pump, and the head increased by 16%. Additionally, the bionic design reduced the maximum far-field sound pressure level by 12.5%, achieving significant noise reduction. This study demonstrates that the bionic design effectively controls dynamic flow separation, reduces flow-induced noise, and enhances the mixed-flow pump's performance. These findings have important theoretical and practical implications for optimizing mixed-flow pump design, improving energy efficiency, and reducing noise. [ABSTRACT FROM AUTHOR]

There is a global move to advocate for the incorporation of Indigenous Knowledges into conservation and land management programs. In Australia this is being reflected in some programs and also regularly in strategy documents. However, we argue that this rarely reflects self-determination for Traditional Custodians. In this article we use two Culturally Significant Entities (CSEs), the humpback and southern right whales, to demonstrate how the regulatory framework that is in place to support species conservation does not adequately allow for Traditional Custodians to extend culturally appropriate levels of care for Country or preserve the knowledge held or associated with a species. Our aim is that the Australian Government and people will work with us to find a way to support the care of CSEs. Position statement: We, the authors, are Indigenous Australians. We have familial connections to whale Lore Holders and/or hold traditional whale Lore/Law as part of our cultural obligations. It is from this position that we advocate for greater care of the whales with which we have Ancestral kinship and reciprocal responsibility. Government, and conservation non-government organisations (NGOs) must incorporate Indigenous Knowledges and priorities into conservation and land management programs to be consistent with self-determination. Our perspective piece outlines caring for Country by acknowledging and protecting Culturally Significant Entities, using case-studies of two whale species. We weave the cultural significance and conservation context of southern right and humpback whales to highlight the inability of contemporary conservation approaches to effectively protect the tangible and intangible elements of Cultural Heritage and knowledge associated with a species. Painting of Gurawal's Songline by Back to Country. This article belongs to the Collection Indigenous and cross-cultural wildlife research in Australia. [ABSTRACT FROM AUTHOR]

The operating conditions of wind turbines are changeable, and the flow separation limits the power generation capacity. In order to improve the output power of wind turbines, based on the principle of bionics, the leading-edge protuberance (LEP) of the humpback whale flipper is introduced to the blade. The optimization of LEP parameters and distribution on the blade performance is studied. The shape and distribution of nonlinear, non-uniform LEPs are controlled by three design variables: amplitude, attenuation, and number. The optimization system consists of modules such as model generation, computational fluid dynamics, and genetic algorithm. The results show that the optimized bionic wind turbine can increase the output power by 3.95% under the rated condition. The optimized LEP structure can improve the performance of the trough sections without sacrificing part of the performance of peak sections, with a maximum increase of 20%. The theory of entropy production is used to analyze the location of energy loss and its impact on the wake. The distribution of the local entropy production rate of the wind turbine wake after optimization is improved. The power spectral density analysis shows that the LEPs cause different variation laws in the wake from the original wind turbine. [ABSTRACT FROM AUTHOR]

Cook Inlet beluga (CIB), Delphinapterus leucas, have not recovered from subsistence overharvest despite conservation efforts initiated in 2000. Reasons for this lack of recovery are still unclear with anthropogenic noise identified as a high threat in this population's recovery plan. Baseline information on CIB habitat use and soundscape characterization is crucial in evaluating impacts from anthropogenic activities. Using passive acoustic monitoring, we documented the seasonality and foraging occurrence of CIB, together with killer whale (Orcinus orca), harbor porpoise (Phocoena phocoena) and humpback whale (Megaptera novaeangliae), for one year in Chinitna and Tuxedni bays and rivers, two historically important but recently overlooked areas of their critical habitat in western lower Cook Inlet, Alaska. This area's ecological interest converges with planned mining, marine renewable energy, offshore oil and gas production, and commercial shipping. Results revealed higher presence of harbor porpoise, killer whale, and humpback whale in Chinitna compared to Tuxedni but much lower CIB presence. CIB were not detected in Chinitna Bay but were in the river on 21 days September-February and one day in June. However, CIB were never detected feeding in Chinitna River. CIB acoustic crypsis and preferential use of very shallow habitat in Chinitna revealed a perceived predation risk from killer whales. In contrast, CIB were recorded foraging in both Tuxedni Bay and River and were detected September-April on 127 days making it an important winter foraging ground. Low levels of anthropogenic noise disturbance were quantified in both bays making them some of the most undisturbed sections of their critical habitat, but at the same time highly sensitive to further noise disturbance. Commercial shipping was the main noise source likely causing acoustic disturbance to CIB due to communication masking despite current low levels of temporal overlap with beluga presence. We recommend that applicable regulators consider restricting high sound producing anthropogenic activities in and adjacent to Tuxedni Bay from September 1st to May 15th when CIB are actively using this area. Managing future anthropogenic activities to minimize habitat degradation and acoustic disturbance in this winter foraging refuge will be a key component to support the recovery of this endangered population. [ABSTRACT FROM AUTHOR]

Biological productivity in the Southern Ocean is modulated by iron availability. Every summer, a large phytoplankton bloom forms northwest of the Ross Sea, above the Antarctic Australian Ridge (AAR), due to a plume of iron‐rich waters. Here, we investigate the origin and trajectories of these iron‐rich waters by analyzing water mass observations and Lagrangian experiments. Output from the Southern Ocean State Estimate (SOSE) and in situ measurements reveal that iron‐rich AAR bloom waters share properties with Modified Circumpolar Deep Water (MCDW), which forms on the Antarctic shelf‐slope. The Lagrangian experiments are conducted using SOSE velocities. Bloom waters tracked with virtual Lagrangian particles highlight an along isopycnal pathway of MCDW from Antarctica's shelf‐slope to the AAR bloom site, illustrating advection of these waters by the Balleny Gyre. These results are supported by temperature‐salinity analyses, which show a correlation between waters advected northwards; MCDW properties; and high iron concentrations. Plain Language Summary: The biological productivity in the Southern Ocean is limited by the availability of iron and light. During the summer, when light is abundant, a current of iron‐rich waters allows the formation of a phytoplankton bloom on the Pacific sector of the Southern Ocean, above the Australian Antarctic Ridge (AAR). The AAR bloom has an average area of 266,000 km2 and has been observed by satellites for more than 20 years. The temporal and spatial consistency of this bloom has important ecological implications. For example, it is a persistent feeding ground for humpback whales. In this work, we use observations and model output to characterize the properties of these iron‐rich waters and their origin. Our analyses suggest that these iron‐rich waters form near the Antarctic shelf and are transported to the AAR bloom area by the local circulation. Quantifying the connectivity between iron sources and the surface is crucial to better monitor Southern Ocean ecosystems as well as their impact on carbon sequestration. Key Points: The Antarctic Australian Ridge phytoplankton bloom's cooler, iron‐rich waters share properties with Modified Circumpolar Deep WaterLagrangian simulations reveal pathways for iron supply from the Antarctic shelf‐slope to the bloom site following the Balleny GyreThe cooler, iron‐rich waters at the bloom site are correlated with northward Lagrangian displacements after a year of advection [ABSTRACT FROM AUTHOR]

Baleen whales are key consumers in marine ecosystems and can serve as ecosystem sentinels. Body condition, defined as an individual’s energy stores relative to its structural size, can provide a useful proxy for health in baleen whales. As capital breeders, important life history events in baleen whales such as seasonal migrations and reproduction depend on having sufficient energy stores. Spatiotemporal variability of body condition of baleen whales can reflect differences in energy accumulated during the foraging season. Here we assess and compare the body condition and mass of humpback whales (Megaptera novaeangliae) across four different foraging areas from the West Indies distinct population segment in the Northwest Atlantic. Morphometric measurements of humpback whales were obtained using unoccupied aerial systems (UAS, or drones) from the New York Bight, the Gulf of Maine, Iceland, and Greenland. Uncertainty in morphometric estimates was incorporated and propagated using a bootstrapping approach. Measurements were used to estimate body volume and calculate a body condition index (BCI) for each individual whale. Since body mass is a key parameter for understanding animal physiology and bioenergetics, we further compared whale body mass to body size between foraging areas by converting body volume to body mass using estimates of tissue density from tagging studies. BCI showed significant differences between foraging areas with a large effect size (ANCOVA: mean η² = 0.168; all p< 0.001) when incorporating day of year and year as covariates. Humpback whales in the Gulf of Maine showed significantly higher BCI than those in the New York Bight, Iceland, and Greenland. Standardized Major Axis (SMA) regressions comparing log-log relationships of both body volume and body mass, respectively, to total length reinforced these results. Humpback whales in the Gulf of Maine showed significantly higher elevation in the SMAs than those in the other study regions (p<0.001), implying that humpback whales foraging in the Gulf of Maine accumulated greater energy reserves for a given body size. Estimates of body mass indicate that for a given body length, humpback whales in the Gulf of Maine have an 18% greater body mass than those in the New York Bight, Iceland, or Greenland. Regional differences in prey availability or anthropogenic threats could contribute to the observed patterns in body condition. Our findings highlight the importance of regional environmental factors to the nutritional health of baleen whales. [ABSTRACT FROM AUTHOR]

Humpback whales in Bermuda have been observed engaging in a unique behavior of expanding their oral pouches and rubbing them against the seafloor. This behavior is believed to be a method of skin maintenance in areas where barnacles and whale lice congregate. The whales were observed swimming together, often in pairs, and descending into sand holes to rub their expanded pouches against the bottom. This behavior is different from feeding and may serve as a way for the whales to exfoliate and clean hard-to-reach areas of their bodies. Further research is needed to fully understand this behavior. [Extracted from the article]

This article discusses a study on bubble trails produced by Eden's whales in the South China Sea. The study found that bubble production is not limited to certain types of whales, but is also observed in baleen whales. The researchers observed bubble trails being produced by solitary individuals as well as pairs of whales. The behavior was documented through field surveys using video cameras and unmanned aerial vehicles. The findings contribute to our understanding of the behavior and ecology of Eden's whales. Further research is needed to better understand the causes and implications of this behavior. [Extracted from the article]

This article discusses the first documented observation of sexual behavior between two male humpback whales. The researchers observed one emaciated whale with a jaw injury being pursued and penetrated by another whale, who held it in place with its pectoral fins. While nonreproductive sexual behavior is common in many species, humpback whale sexual behavior remains largely undescribed. The significance and contexts of these behaviors in humpback whale social interactions require further study. [Extracted from the article]

This article discusses a study on estimating the population size of Eastern Caribbean sperm whales for conservation purposes. The researchers conducted surveys in the Lesser Antilles region and used photo identification and acoustic data to estimate the population size. They found that the population is structured at a small spatial scale and that previous data from Dominica is biased and does not represent the entire population. The study provides more accurate population estimates for sperm whales in the region and emphasizes the need to consider different vocal clans separately in conservation efforts. The study also highlights the limitations of the methods used and the importance of cultural diversity in conservation. [Extracted from the article]

This article discusses a study on humpback whale vocalizations in a mid-latitude, winter feeding ground in Virginia. The researchers were unable to determine the sex of the whale, but they found that it vocalized for a significant amount of time, producing 11 distinct call types. They also identified patterns and themes in the whale's vocalizations, suggesting the presence of song fragments. The researchers hypothesize that the tagged whale was a juvenile male practicing singing behavior. The article also highlights the threat of vessel strikes to humpback whales, particularly in the U.S. Atlantic Coast, where ship traffic is increased. The researchers suggest that the whale's passive, head-down orientation during vocalizations may increase its vulnerability to ship strikes. Overall, this study contributes to our understanding of humpback whale behavior and the risks they face in their feeding grounds. [Extracted from the article]

Large whale entanglements are considered a significant threat to populations on a global scale. In the Mexican Pacific and Baja California Peninsula (1996–2021) a total of 218 confirmed entangled whales, from which 99 (45.4%) whales were fully released (66 by the Mexican Whale Disentanglement Network, known as RABEN). Five whale species were reported in confirmed entanglements: humpback (Megaptera novaeangliae, n = 187), gray (Eschrichtius robustus, n = 19), sperm (Physeter macrocephalus, n = 5), Bryde's (Balaenoptera edeni, n = 4), and fin (Balaenoptera physalus, n = 3). Eight types of fishing gear were identified out of 209 different gear sets; gill nets were the most common (n = 101, 48.3%), followed by pots (n = 49, 23.4%). Entanglements were reported in sixteen locations, and Banderas Bay had the most entanglement reports (n = 81, 32.8%). Several entanglements were tracked across multiple locations (n = 7), involving two teams with the most successful releases (n = 5), proving the efficiency of the RABEN entanglement response network. This information can be used to better understand entanglement impacts on large whales in the North Pacific and particularly in Mexico, to work towards mitigation of a problem that affects both whales and fishermen. [ABSTRACT FROM AUTHOR]

The major histocompatibility complex (MHC) is a highly polymorphic gene family that is crucial in immunity, and its diversity can be effectively used as a fitness marker for populations. Despite this, MHC remains poorly characterised in non‐model species (e.g., cetaceans: whales, dolphins and porpoises) as high gene copy number variation, especially in the fast‐evolving class I region, makes analyses of genomic sequences difficult. To date, only small sections of class I and IIa genes have been used to assess functional diversity in cetacean populations. Here, we undertook a systematic characterisation of the MHC class I and IIa regions in available cetacean genomes. We extracted full‐length gene sequences to design pan‐cetacean primers that amplified the complete exon 2 from MHC class I and IIa genes in one combined sequencing panel. We validated this panel in 19 cetacean species and described 354 alleles for both classes. Furthermore, we identified likely assembly artefacts for many MHC class I assemblies based on the presence of class I genes in the amplicon data compared to missing genes from genomes. Finally, we investigated MHC diversity using the panel in 25 humpback and 30 southern right whales, including four paternity trios for humpback whales. This revealed copy‐number variable class I haplotypes in humpback whales, which is likely a common phenomenon across cetaceans. These MHC alleles will form the basis for a cetacean branch of the Immuno‐Polymorphism Database (IPD‐MHC), a curated resource intended to aid in the systematic compilation of MHC alleles across several species, to support conservation initiatives. [ABSTRACT FROM AUTHOR]

Rationale: Stable isotope analysis (SIA) of free‐swimming mysticetes using biopsies is often limited in sample size and uses only one sample per individual, failing to capture both intra‐individual variability and the influence of demographic and physiological factors on isotope ratios. Methods: We applied SIA of δ13C and δ15N to humpback whale (Megaptera novaeangliae) biopsies taken during the foraging season along the western Antarctic Peninsula to quantify intra‐individual variation from repeatedly sampled individuals, as well as to determine the effect of biopsy collection site, sex, and pregnancy on isotope ratios. Results: There was substantial variability in δ13C from multiple biopsies taken from the same individuals, though δ15N was much more consistent. Side of the body (left versus right) and biopsy location (dorsal, anterior, ventral, and posterior) did marginally affect the isotopic composition of δ15N but not δ13C. Pregnancy had a significant effect on both δ13C and δ15N, where pregnant females were depleted in both when compared to non‐pregnant females and males. Conclusions: These results indicate that isotopic signatures are influenced by multiple endogenous and exogenous factors and emphasize value in accounting for intra‐individual variability and pregnancy status within a sampled population. Placed within an ecological context, the endogenous variability in δ13C observed here may be informative for future isotopic analyses. [ABSTRACT FROM AUTHOR]

The Salish Sea supports several baleen whale species, including humpback (Megaptera novaeangliae), gray (Eschrichtius robustus) and minke whales (Balaenoptera acutorostrata). With the exception of minke whales, these species were decimated by commercial whaling in the 1900s. Because recovery of these populations is monitored on broad spatial scales determined by stocks or populations, their use of the Salish Sea ecosystem is not well documented or understood. We collated 17,436 opportunistic sighting reports to assess patterns in mysticete presence and distribution in the Salish Sea (1976-2019). We used the proportion of sightings for each species and spatial models targeting comparisons between species to limit the influence of spatio-temporal variation in reporting efforts. Humpback whale sightings have increased dramatically since the late 2000s, mirroring population-wide increases and suggesting a renewed use of historically important feeding areas. Gray whale sightings increased most notably at two distinct times (1989, 2017), both of which align with periods of high mortality experienced by the delisted Eastern North Pacific stock of gray whales and may reflect individuals straying from their migration routes. Sightings of minke whales remained relatively stable over this study period and were likely driven by a group of 30-40 individuals that forage off shallow banks and bathymetrically complex habitats around the San Juan Archipelago. Though it can be difficult to separate the bias that accompanies public sightings databases, citizen science efforts are invaluable for monitoring the recovery of rebounding populations and can illuminate longitudinal patterns that would otherwise go unnoticed. [ABSTRACT FROM AUTHOR]

This investigation into the aerodynamic efficiency and structural integrity of tubercle leading edges, inspired by the agile maneuverability of humpback whales, employs a multifaceted experimental and computational approach. By utilizing static load extensometer testing complemented by computational simulations, this study quantitatively assesses the impacts of unique wing geometries on aerodynamic forces and structural behavior. The experimental setup, involving a Wheatstone full-bridge circuit, measures the strain responses of tubercle-configured leading edges under static loads. These measured strains are converted into stress values through Hooke's law, revealing a consistent linear relationship between the applied loads and induced strains, thereby validating the structural robustness. The experimental results indicate a linear strain increase with load application, demonstrating strain values ranging from 65 με under a load of 584 g to 249 με under a load of 2122 g. These findings confirm the structural integrity of the designs across varying load conditions. Discrepancies noted between the experimental data and simulation outputs, however, underscore the effects of 3D printing imperfections on the structural analysis. Despite these manufacturing challenges, the results endorse the tubercle leading edges' capacity to enhance aerodynamic performance and structural resilience. This study enriches the understanding of bio-inspired aerodynamic designs and supports their potential in practical fluid mechanics applications, suggesting directions for future research on manufacturing optimizations. [ABSTRACT FROM AUTHOR]

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Context: Humpback whale (Megaptera novaeangliae) populations have been recovering from whaling but are now facing threats from changing food availability due to ocean warming and changes in habitat suitability. There is uncertainty over whether opportunistic observations can produce reliable species distribution models (SDMs) and adequately inform conservation management. Aims: To compare SDMs for humpback whales in the Great Barrier Reef Marine Park based on different opportunistic sightings datasets and evaluate the impact different sources of opportunistic data have on our understanding of humpback whale habitat relationships. Methods: Maximum entropy modelling (Maxent) was used to create predictive models for humpback whale distributions. Sighting data from citizen science and opportunistic observations from various other databases were used. Models were compared to evaluate disparities and predictive capabilities. Key results: Distinct environmental variables [bathymetry, distance to the coast] were identified as the most relevant for each SDM. The best-fitting model diverged from an existing model, with humpback whale distribution predicted to be closer to shore. Areas with the highest habitat suitability were concentrated in the north-eastern coastal region across all models developed in this study. Conclusions: This study demonstrates that, with careful application and consideration, citizen science data can enhance our understanding of humpback whale distributions and contribute to their conservation. The research underlines the importance of embracing diverse data sources in SDM, despite the challenges posed by opportunistic data. Implications: The study provides valuable insights for conservation management and informs strategies to protect humpback whale populations in changing environmental conditions. Understanding the habitat relationships of humpback whales in the Great Barrier Reef is key for conservation. This study compares species distribution models based on different opportunistic sightings datasets, revealing distinct significance of environmental factors. The findings inform strategies to protect humpback whale populations in the face of changing environmental conditions. [ABSTRACT FROM AUTHOR]

Studying sound production at different developmental stages can provide insight into the processes involved in vocal ontogeny. Humpback whales (Megaptera novaeangliae) are a known vocal learning species, but their vocal development is poorly understood. While studies of humpback whale calves in the early stages of their lives on the breeding grounds and migration routes exist, little is known about the behavior of these immature, dependent animals by the time they reach the feeding grounds. In this study, we used data from groups of North Atlantic humpback whales in the Gulf of Maine in which all members were simultaneously carrying acoustic recording tags attached with suction cups. This allowed for assignment of likely caller identity using the relative received levels of calls across tags. We analyzed data from 3 calves and 13 adults. There were high levels of call rate variation among these individuals and the results represent preliminary descriptions of calf behavior. Our analysis suggests that, in contrast to the breeding grounds or on migration, calves are no longer acoustically cryptic by the time they reach their feeding ground. Calves and adults both produce calls in bouts, but there may be some differences in bout parameters like inter-call intervals and bout durations. Calves were able to produce most of the adult vocal repertoire but used different call types in different proportions. Finally, we found evidence of immature call types in calves, akin to protosyllables used in babbling in other mammals, including humans. Overall, the sound production of humpback whale calves on the feeding grounds appears to be already similar to that of adults, but with differences in line with ontogenetic changes observed in other vocal learning species. [ABSTRACT FROM AUTHOR]

Seven passive acoustic surveys for marine mammal sounds were conducted by deploying sonobuoys along ship tracks during Antarctic voyages spanning years 2006-2021. These surveys included nearly 330° of longitude throughout Antarctic (south of 60°S) and sub-Antarctic (between 50-60°S) latitudes. Here, we summarise the presence of calls from critically endangered Antarctic blue whales (Balaenoptera musculus intermedia) detected on all seven of these surveys. We describe and compare the spatial distribution of detections of three different types of Antarctic blue whale calls: unit-A, Z-calls, and D-calls. Three sets of voyages partially overlapped spatially but in different years, providing three regions (Indian Sector, Dumont d'Urville Sea, Ross Sea) to investigate differences over time for these three different call types. The proportion of sonobuoys with calls present was significantly higher in the more recent years for seven of the 15 combinations of years, regions, and call type. The proportion of sonobuoys with calls present was significantly lower only for one of the 15 combinations (unit A in the Ross Sea between 2015 vs 2017), and not significantly different for the remaining seven pairwise comparisons. We discuss possible explanations for these observations including: differences in probability of detection, whale behaviour, whale distribution, and abundance. These explanations are not mutually exclusive and cannot yet be resolved without application of complex analytical methods and collection of additional data. Lastly, we discuss future work that could help clarify the contributions of each of these potential drivers of acoustic detection. We propose continued acoustic data collection, application of new analytical methods, and collection of other synergistic data from Antarctic blue whales on their feeding grounds as a basis for future work on this species. This could provide a cost effective and holistic means of monitoring their status after the effects of 20th century industrial whaling, as well as their responses to natural and anthropogenic changes to their main prey, Antarctic krill, and a changing climate. [ABSTRACT FROM AUTHOR]

The humpback whale (Megaptera novaeangliae) is a cosmopolitan migratory, seasonal mysticete that frequents the Brazilian coast. Strands of specimens may occur during the migratory stay in the country. In 2021 and 2022, three live humpback whales stranded on the coast of Rio Grande do Sul and Santa Catarina states in southern Brazil. After euthanasia, specimens were necropsied, and organs were thoroughly examined for lesions. Grossly, in all three cases, the liver exhibited multifocal, irregular, firm, white areas on the hepatic capsule, which extended into the parenchyma. On the cut surface, the livers were yellow to pale brown with orangish to greenish areas, the bile ducts were prominent, thickened, and severely dilated, and leaf-shaped flukes were found inside of them. Additionally, one case showed moderate atrophy of the right hepatic lobe. The histological findings included dilation of bile ducts, hyperplasia of the bile duct epithelium, marked inflammatory infiltration of lymphocytes, plasma cells, and eosinophils, and portal fibrosis. The parasite Brachycladium goliath was both morphologically and molecularly identified based on diagnostic key for trematodes and the original description of the species, and the amplification and sequencing of the ITS-2 region, respectively. Even though hepatic injury was not the primary cause of stranding, it may have contributed to the debilitation of the whales. To the authors’ knowledge, this is the first study that reports M. novaeangliae as a definitive host of B. goliath and that describes the lesions caused by the parasite in cetaceans. [ABSTRACT FROM AUTHOR]

This article explores the cultural evolution of humpback whale songs in the South Atlantic, specifically focusing on changes observed in Brazil between 2017 and 2018. The study reveals a significant shift in the complexity of the songs, suggesting a cultural revolution within the humpback whale population. The authors propose that these revolutions are a result of cultural exchange between different populations during the nonbreeding season, facilitated by the lack of physical barriers in the Southern Hemisphere. The research emphasizes the importance of acoustic interactions in understanding the dynamics of humpback whale songs and highlights the need for further study in this area. [Extracted from the article]

This article reports the first direct observation of a successful southern right whale birth in South African coastal waters. Southern right whale females typically migrate to coastal areas in South Africa to give birth and nurse their young. The calving season extends from late June to late October, with a peak in August. Despite long-term research efforts, very little is known about the birthing event in southern right whales. The article describes the observation of a lone southern right whale performing unique behaviors, followed by the birth of a calf. The mother did not assist the calf immediately after birth, which is consistent with behavior observed in other successful cetacean births. The article highlights the value of opportunistic data and the need for further research to improve our understanding of cetacean behavior and ecology. [Extracted from the article]

This article presents a study on estimating tidal lung volumes (VT) in adult gray whales using audio and video recordings. The researchers used unmanned aerial systems (UAS) to monitor foraging whales in coastal waters and compared their findings to previous studies conducted in a winter breeding/calving lagoon. The results indicate that tidal lung volume can be estimated based on body length and exhalation duration. This method provides a new tool for understanding the metabolic rate and resource requirements of gray whales, as well as the impact of changing oceanographic conditions on their prey availability. [Extracted from the article]