Humpback Whales Research Articles

Distribution models of baleen whale species in the Irish Exclusive Economic Zone to inform management and conservation

Irish waters are under increasing pressure from anthropogenic sources including the development of offshore renewable energy, vessel traffic and fishing activity. Spatial planning requires robust datasets on species distribution and the identification of important habitats to inform the planning process. Despite limited survey effort, long-term citizen science data on whale presence are available and provide an opportunity to fill information gaps. Using presence-only data as well as a variety of environmental variables, we constructed seasonal ensemble species distribution models based on five different algorithms for minke whales, fin whales, humpback whales, sei whales, and blue whales. The models predicted that the coastal waters off the south and west of Ireland are particularly suitable for minke, fin and humpback whales. Offshore waters in the Porcupine Seabight area were identified as a relevant habitat for fin whales, sei whales and blue whales. We combined model outputs with data on maritime traffic, fishing activity and offshore wind farms to measure the exposure of all the species to these pressures, identifying areas of concern. This study serves as a baseline for the species presence in Irish waters over the last two decades to help develop appropriate marine spatial plans in the future.

Characterization of Cetacean Morbillivirus in Humpback Whales, Brazil.

Cetacean morbillivirus is an etiologic agent associated with strandings of live and dead cetacean species occurring sporadically or as epizootics worldwide. We report 2 cases of cetacean morbillivirus in humpback whales (Megaptera novaeangliae) in Brazil and describe the anatomopathological, immunohistochemical, and molecular characterization findings in the specimens.

Numerical investigation of cavitation suppression of centrifugal pump based on the bionic humpback whale blade

Abstract Cavitation is inevitable during the operation of centrifugal pumps, it leads to the decrease in head and efficiency, and induced pressure fluctuation. This paper takes low specific speed centrifugal pump as the research object, a method of inhibiting cavitation by bionic humpback whale blade is proposed, the SST turbulence model is used to numerically study the whole flow passage of centrifugal pump. Comparative analysis of the cavitation characteristic curves under design conditions, the effects of bionic blades on water vapour volume fraction distribution, static pressure distribution, turbulent kinetic energy, vorticity field, streamline were investigated, the variation laws of cavitation morphology under different cavitation numbers is clarified. The research provides theoretical support for improving the cavitation performance and operation stability of centrifugal pump.

Contributions of the internship at the Humpback Whale Project to academic training: experience report

Contributions of the internship at the Humpback Whale Project to academic training: experience report

Study on the Influence of Protuberance Amplitude on the Performance of Vertical Axis Wind Turbines

Abstract The performance of vertical axis wind turbine (VAWT) is mainly affected by the dynamic stall process of the blade. Inspired by the anti-stall performance of the humpback whale flipper, leading edge protuberances (LEPs) are applied to 2-blade VAWT. Based on computational fluid dynamics simulation method, the effects of LEPs amplitude on VAWT performance are investigated when blade tip speed ratio is 2.19. The results show that the larger the amplitude of the LEP, the lower the average power coefficient. When the number of protuberances is 3, the average power coefficient of the VAWT with a protuberance amplitude of 6.625mm is 1.8% higher than prototype blade. Considering the impact of increasing the chord length of biomimetic blades, the average tangential force coefficient of all biomimetic VAWTs decreases. The peak section performance of the bionic blade decreases significantly while the trough section performance increases significantly. The difference between the peak section and trough section of the LEPS plays an important role in improving the performance. This study provides a reference for the application of bionic protuberances in VAWTs.

Acoustic behavior of humpback whale calves on the feeding ground: Comparisons across age and implications for vocal development.

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.

Evaluating drivers of recent large whale strandings on the East Coast of the United States.

Anthropogenic stressors threaten large whales globally. Effective management requires an understanding of where, when, and why threats are occurring. Strandings data provide key information on geographic hotspots of risk and the relative importance of various threats. There is currently considerable public interest in the increased frequency of large whale strandings occurring along the US East Coast of the United States since 2016. Interest is accentuated due to a purported link with offshore wind energy development. We reviewed spatiotemporal patterns of strandings, mortalities, and serious injuries of humpback whales (Megaptera novaeangliae), the species most frequently involved, for which the US government has declared an "unusual mortality event" (UME). Our analysis highlights the role of vessel strikes, exacerbated by recent changes in humpback whale distribution and vessel traffic. Humpback whales have expanded into new foraging grounds in recent years. Mortalities due to vessel strikes have increased significantly in these newly occupied regions, which show high vessel traffic that also increased markedly during the UME. Surface feeding and feeding in shallow waters may have been contributing factors. We found no evidence that offshore wind development contributed to strandings or mortalities. This work highlights the need to consider behavioral, ecological, and anthropogenic factors to determine the drivers of mortality and serious injury in large whales and to provide informed guidance to decision-makers.

Defining humpback whale (Megaptera novaeangliae) potential distribution in the Great Barrier Reef Marine Park: a two-way approach

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.

Exploring habitat use and movement patterns of humpback whales in a reoccupation area off Brazil: A comparison with the Abrolhos Bank

AbstractAfter 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.

Humpback whale (Megaptera novaeangliae) social calls in southern British Columbia

AbstractHumpback 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.

Pathological, morphological, and molecular characterization of the infection by Brachycladium goliath in humpback whale Megaptera novaeangliae.

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.

Investigation of dynamic characteristics of hydrofoil with leading-edge tubercles

The convex structure of a humpback whale flipper is included in the airfoil design to investigate the control principle of the dynamic stall process. The effect of two different types of tubercles on the dynamic stall process of airfoils was investigated. The distribution of dynamic hysteresis loops and pressure fields with streamlines was used to explain the properties of the dynamic flow field and the emergence of dynamic stall vortices. The results demonstrate that the airfoils with tubercles have stronger hysteretic characteristics in the pre-stall region, and the ζ CM of mod-1 is increased by 51.33%, indicating stronger torsional hydroelastic stability. In the post-stall region, mod-2 is always in a condition of significant flow separation, which impairs the torsional hydrodynamic stability of the airfoil and has the potential to cause flutter. These findings suggest that leading-edge tubercles offer a negligible advantage in reducing airfoil dynamic stall, and their significance warrants further investigation.

Cellular Redox Status of Dermal fibroblasts as a Model to Explore Hypoxia Responses Across Diverse Mammals

Specializations in energy production pathways can define phenotype in mammals, enabling resilience to environmental stressors and survival in extreme habitats. Most mammals rely on oxygen-based mitochondrial respiration to sustain high rates of ATP production necessary for homeothermy; oxidative phosphorylation is fueled by donation of reducing equivalents (NADH, FADH2) to the electron transport chain. As such, relative redox levels within the cell (NAD+/NADH ratio) indicate cell health and metabolic status. In hypoxic conditions, cells can experience reductive stress, evidenced by a buildup of NADH and altered NAD+/NADH ratio. We are using primary dermal fibroblasts isolated from skin biopsies in n=9 species to compare metabolic changes via the ratio between NAD+ and NADH when exposed to 0.5% O2 for 6-h and 24-h. Species were selected to encompass diverse phylogeny as well as to include species that are adapted to low oxygen environments (high altitude gelada baboons, diving humpback whales and Weddell seals). Control species without adaptation to hypoxic environments included human, dromedary camel, little brown bat, honey badger, and rhinoceros. We expect fibroblasts from species adapted to living with variable oxygen availability to have more stability in NAD+/ NADH ratios when exposed to hypoxia in cell culture compared to those from species that are not adapted to low oxygen environments. We quantified NAD+ and NADH following exposure to hypoxia as well as control normoxic samples. Preliminary data with n=3 biological replicates per species show that fibroblasts from the control animals display significant differences in NAD+/NADH ratio between normoxic and hypoxic treatments (Kruskal-Wallis test, p=0.01), however, there are no significant differences in the ratios presented for tolerant animals (Kruskal-Wallis test, p=0.518). This finding supports our hypothesis that animals adapted to low oxygen reduce variability in the NAD+/NADH ratios. Understanding the metabolic patterns when cells are exposed to reduced oxygen levels can provide a framework for estimating a species resilience to environmental variation. Funded by NSF #2022046, CSUN-OUR Summer Undergraduate Fellowship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effects of satellite-linked telemetry tags on humpback whales in the Gulf of Maine: Photographic assessment of tag sites

Effects of satellite-linked telemetry tags on humpback whales in the Gulf of Maine: Photographic assessment of tag sites

Southern Ocean humpback whale trophic ecology. I. Combining multiple stable isotope methods elucidates diet, trophic position and foraging areas

Southern Ocean humpback whales Megaptera novaeangliae are capital breeders, breeding in the warm tropics/subtropics in the winter and migrating to nutrient-rich Antarctic feeding grounds in the summer. The classic feeding model is for the species to fast while migrating and breeding, surviving on blubber energy stores. Whilst northern hemisphere humpback whales are generalists, southern hemisphere counterparts are perceived as krill specialists, but for many populations, uncertainties remain regarding their diet and preferred feeding locations. This study used bulk and compound-specific stable isotope analyses and isoscape-based feeding location assignments to assess the diet, trophic ecology and likely feeding areas of humpback whales sampled in the Ross Sea region and around the Balleny Islands. Sampled whales had a mixed diet of plankton, krill and fish, similar to the diet of northern hemisphere humpback whales. Proportions of fish consumed varied but were often high (2-60%), thus challenging the widely held paradigm of Southern Ocean humpback whales being exclusive krill feeders. These whales had lower 15N values and trophic position estimates than their northern hemisphere counterparts, likely due to lower Southern Ocean baseline 15N surface water values and a lower percentage consumption of fish, respectively. Most whales fed in the Ross Sea shelf/slope and Balleny Islands high-productivity regions, but some isotopically distinct whales (mostly males) fed at higher trophic levels either around the Balleny Islands and frontal upwelling areas to the north, or en route to Antarctica in temperate waters off southern Australia and New Zealand. These results support other observations of humpback whales feeding during migration, highlighting the species’ dietary plasticity, which may increase their foraging and breeding success and provide them with greater resilience to anthropogenically mediated ecological change. This study highlights the importance of combining in situ field data with regional-scale isoscapes to reliably assess trophic structure and animal feeding locations, and to better inform ecosystem conservation and management of marine protected areas.

Southern Ocean humpback whale trophic ecology. II. Influence of fasting and opportunistic feeding on skin stable isotope values of migrating whales

Many baleen whale species migrate between low-latitude breeding grounds and high-latitude feeding grounds, with increasing evidence that humpback whales Megaptera novaeangliae utilise supplemental feeding sites in temperate regions while migrating. The diet of whales while migrating is often unknown, and the impact that temperate feeding and/or fasting has on biochemical tracers used to investigate diet remains unclear. The aims of this study were to (1) determine whether prey consumption at supplemental feeding sites could be detected by carbon (13C) and nitrogen (15C) stable isotope analysis of skin; (2) obtain information on diet during migration; and (3) ascertain the impact of potential fasting on stable isotope values of baleen whales. Skin samples were taken from the eastern Australian humpback whale population on Antarctic feeding grounds and 2 sites on the southward migration route (a sub-tropical site and a temperate site) across 2 yr. At the sub-tropical site, 13C and δ15N were consistent with the last place of foraging 5 mo earlier. One exception was the higher (0.5 ‰) δ15N value in 2011, suggesting that in some years, potentially when blubber reserves are insufficient, δ15N may be influenced by fasting. In both years, skin 13C and δ15N values at the temperate site were higher than those from the Antarctic and sub-tropical sites, indicating that a feeding signal from temperate zones had likely been incorporated, with whales feeding on fish and krill. Importantly, supplemental feeding while migrating could affect the interpretation of whale diet on feeding grounds if sampled early in the season.

Time budget and behavioral synchrony of humpback whale mother‐calf pairs on a breeding ground in the southwestern Indian Ocean

AbstractUnderstanding the activity budget of mother‐young pairs can inform how energy is allocated and its relation to the development of young. Using suction cup tag data collected off Sainte Marie, Madagascar, during the calving season, we compared the time budgets of mothers and their calves in capital‐breeding humpback whales, investigated the changes with age, and assessed mother‐calf behavioral synchrony based on their swimming speed. We found that mothers and calves allocated much of their time to low‐level activities (i.e., static/quasi‐static or swimming at low speed). Young calves engaged more in slow swimming than older calves and mothers. Mothers with younger calves tended to stay static or quasi‐static less than mothers with older ones. Calves displayed some degree of independence in activities but were also observed synchronizing their activities with their mothers. Depending on the nature of the activity, the initiation of it was driven by either the calf or the mother. Our study provides additional knowledge for understanding the behavioral dynamics and interactions within humpback whale mother‐calf pairs. It provides data that can support the implementation of conservation measures.

Baleen whale microsatellite panel for individual identification and parentage assignment in Mysticeti

Highly polymorphic single tandem repeat loci (STR, also known as microsatellite loci) remain a familiar, cost efficient class of genetic markers in genetic studies in ecology, behavior and conservation. Here we characterize a new, universal set of ten STR loci in seven species of baleen whales, optimized for PCR amplification in two multiplex reactions along with a Y chromosome marker for sex determination. The optimized, universal set of STR loci provides a convenient starting point for new genetic studies in baleen whales aimed at identifying individuals and populations. Data from the new STR loci were combined with genotypes from previously published STR loci to assess the power to assign parentage using paternity exclusion in four species: fin whale (Balaenoptera physalus), humpback whale (Megaptera novaeangliae), blue whale (B. musculus) and bowhead whale (Balaena mysticetus). Our results suggest that parentage studies should always be accompanied by a power analysis in order to ascertain that each individual specific study is based upon data with sufficient power to assign parentage with statistical rigor.

An Efficient Metaheuristic Technique for Wireless Sensor Network Integrated Micro Grid Environment Using Improved Whale Optimization Algorithm (Iwoa)

Wireless Sensor Network (WSN) nodes require careful power management to maintain long term operation without regular battery changes. Battery replacement can be challenging and expensive in a microgrid scenario where sensors may be installed in remote or i naccessible areas. To extend the life of WSN nodes, energy efficient design and power management strategies should be used. A potential strategy for effectively monitoring, controlling, and managing the distributed energy resources (DERs) inside a microgri d is theincorporation of WSNs with microgrids. This research work uses Improved Whale Optimization Algorithm (WOA) for optimizing the routing and performance. The humpback whale's hunting style served as the inspiration for the WOA, a metaheuristic optimization algorithm. WOA is an optimization technique that is used with MG and WSNs. During the optimization phase, WOA establishes a balance between exploitation and exploration. To increase the lifespan of a WSN in a microgrid, effective energy management i s frequently needed. When considering the dynamic energy availability from renewable sources and the energy requirements of the microgrid components, WOA is used to optimise energy allocation and routing in WSNs. This may lead to increased energy efficiency and longer network longevity. The IWOA attains 97.5% PDR that is higher than the existing state of art techniques.

The influence of biopsy site and pregnancy on stable isotope ratios in humpback whale skin.

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. 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. 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. 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.