Ontogenetic brain growth in cetaceans is essential for understanding their development and evolution. This study investigates brain size changes relative to body growth in bowhead (Balaena mysticetus) and beluga (Delphinapterus leucas) whales in the framework of age estimates of pre- and postnatal specimens. We collected specimens in the field, determined brain size and endocranial volumes, as well as size of endocranial adnexa, either by direct measurement or by CT. We estimated age using baleen length (bowhead), growth layers in teeth (belugas), or fetal stages. We fitted Gompertz growth models to our data. Our findings show that both bowhead and beluga whales reach nearly their full brain size by the end of weaning, unlike dolphins and humans, whose brains continue growing after weaning. Bowhead brains grow faster than those of belugas, and much faster than those of humans, and their rete mirabile occupies a much larger portion of the cranial cavity than in belugas. Encephalization quotients decline with age due to continued body growth after brain maturation. Brain growth in these cetacean species plateaus early, challenging the assumption that cetacean brains grow throughout life. In bowhead, the brain is significantly smaller than the cranial cavity, and this is not the case in beluga. If this observation can be generalized to all mysticetes and odontocetes, it implies that no single equation can capture the proportional volumes of the brain and cranial cavity across the entire cetacean clade.
Body condition, the relative amount of energy reserves in an individual, reflects nutritional status and overall health in marine mammals and can indicate the influence of stressors on individuals. Energy in marine mammals is primarily stored as lipids within adipocytes in blubber tissue, making blubber thickness a common proxy for body condition. However, blubber also serves structural roles, complicating its use as a body condition indicator. Our objective was to assess the relationship between adipocyte size, a common measure of cetacean adiposity, and blubber thickness in beluga whales (Delphinapterus leucas). We used mixed-effect generalized linear models to test how sex and blubber layer influenced this relationship. We found a significant positive relationship between adipocyte size and blubber thickness in male but not female beluga whales, suggesting sex-specific differences in fat storage or mobilization. Blubber thickness may be maintained in female beluga whales during periods with low energy reserves, for example during gestation and lactation, to preserve buoyancy, insulation, and hydrodynamism, which may be especially important when supporting swimming calves. Continuing to develop methods to assess beluga whale health will further our understanding of the impact of current and future stressors on beluga whale populations.
In this paper, a trajectory planning method based on an improved beluga whale optimization algorithm is proposed for the trajectory planning of plasma-spraying robot with complex surfaces. Firstly, the system architecture, kinematics model and trajectory planning constraints of the 6-DOF mobile plasma robot are analyzed, including kinematics, dynamics and environmental constraints, and a constrained-objective optimization function with time optimization, energy consumption and smoothness as objectives is established. Secondly, aiming at the shortage of the balance between global search and local development of the original beluga optimization algorithm, the tent chaotic mapping strategy is introduced to enhance the population diversity, and the sine and cosine algorithm is integrated to optimize the search process, so as to improve the convergence accuracy and stability. The experimental part is verified by the standard test function and the special index of trajectory planning. The results show that the IBWO algorithm is significantly better than the original beluga optimization, particle swarm optimization and other comparative algorithms in convergence accuracy, stability and comprehensive performance. In addition, the trajectory planning example shows that the joint trajectory generated by improved beluga whale optimization is smooth and has high constraint satisfaction, which is suitable for complex surface spraying tasks.
The bony labyrinth of the petrosal bone, a distinctive feature of mammal skulls, is often identified in micro-computed tomography imaging to infer species' physiological and ecological traits. When done as part of a comparative study, one individual specimen is normally considered representative of a species, and intraspecific variation is considered low. Yet tests of intraspecific variability have been performed on few species and on limited morphological traits. Studies of intraspecific variability are not only valuable to help us assess the need for multiple specimens in comparative work, but relative levels of variability can also be used to reveal insights into a trait's functional significance. In this study, we report measurements of intraspecific variation on two cetaceans with vastly different auditory specializations, a low-frequency specialized mysticete and an echolocating odontocete. We examine the internal structures of the cochlea in beluga and bowhead whales and relate this to their hearing abilities. Overall levels of intraspecific variability are higher in the bowhead than the beluga, reflecting the more specialized auditory system of the latter. However, the levels of variation differ through the length of the cochlea (base to apex) and these appear to reflect known frequency specializations of the species, with the bowhead having lower variation in some measurements at the low-frequency apical end than the beluga.
Animal vocalizations can evolve structural features as long-term adaptations to noisy environments. Using such signals, cetaceans could mitigate masking from vessel noise. This study investigates whether beluga whales (Delphinapterus leucas) use ultrasonic high-frequency burst pulse (HFBP) calls to communicate in noisy conditions. We identified HFBP calls in three populations: St Lawrence Estuary, Eastern High Arctic-Baffin Bay, and Western Hudson Bay. Focusing on the industrialized St Lawrence, we investigated the effects of vessel noise on HFBP call rates compared to other call types. Ultrasonic calls, spanning a bandwidth of 36.4±6.5 to 144 kHz (Nyquist frequency), comprised 13% of the St Lawrence beluga repertoire (n=25,435). Noise events (n=21) were defined as periods when at least one vessel was visible within 2 km of the hydrophone while belugas were within 500 m. Sound pressure levels were measured before, during, and after exposure. Generalized linear mixed models revealed consistent HFBP call rates before, during, and after vessel noise exposure, while contact calls and other call types declined during exposure (n=4528). These findings suggest that ultrasonic signals that evolved in the Arctic - where ice-associated noise may have created a need for high-frequency communication - remain a viable communication channel in vessel noise, allowing belugas to exploit these signals to maintain communication. Understanding how belugas use signals in noisy environments can inform conservation strategies for noise-impacted marine mammals.
The world is full of uncertainty, often requiring decisions that involve unknown outcomes. Responses to uncertainty, or risk, have been widely studied, revealing both species-level and individual differences. Risk studies have focused on a few key species, so to increase taxon diversity, we investigated the risk sensitivity of four female beluga whales (Delphinapterus leucas) living under human care. We presented them with two options that had identical mean value but differed in their respective variability. The safe option provided four fish every time it was selected, and the risky option provided either zero or eight fish with equal probability. Belugas' preferences varied, with two whales preferring the safe option and two whales preferring the risky option. Testing across morning and afternoon sessions revealed that satiation, assumed to be higher in the afternoon due to feeding schedules, exacerbated existing tendencies toward the safe option in two whales, but did not change any of the belugas' overall preferences. In addition, whales maintained their preferences irrespective of what they had received on the previous trial. Therefore, within individuals, neither short (previous trial) nor longer (time of day) term contexts influenced individuals' preferences, suggesting that these differences were stable. Our results emphasize the importance of considering individual differences in animal decision-making. (PsycInfo Database Record (c) 2026 APA, all rights reserved).
The growing demand for clean-label food ingredients drives interest in novel marine flavorings. This study evaluated the physicochemical, antioxidant, volatile (GC-MS), and sensory profiles of freeze-dried powders from blue crab roe (Callinectes sapidus), sea urchin roe (Paracentrotus lividus), and beluga caviar (Huso huso) to assess their culinary potential. Results revealed that sensory quality is governed by the synergy between a matrix's lipid composition and endogenous antioxidant capacity. Sea urchin powder, possessing a low polyunsaturated fatty acid (PUFA) profile and high carotenoid content, exhibited exceptional oxidative stability, yielding a concentrated marine aldehyde signature and top consumer scores. Blue crab roe demonstrated a robust PUFA matrix buffered by high phenolic content, facilitating controlled lipid peroxidation into desirable savory volatiles (ketones and aldehydes). Conversely, the high-fat, monounsaturated-dominant beluga caviar lacked sufficient antioxidants, leading to lipid degradation, oxidized hydrocarbons, earthy off-flavors, and poor texture. Both crab and caviar powders exhibited favorable Atherosclerosis and Thrombogenicity indices. Ultimately, balancing lipid composition and endogenous antioxidants is crucial for flavor stability, highlighting the commercial and environmental potential of transforming underutilized or invasive species like blue crab into stable, nutrient-dense marine flavoring agents.
Understanding the role of environmental factors such as pollution and infectious diseases on the health and well-being of free-ranging beluga whales Delphinapterus leucas is essential for their conservation. As part of this effort, 2 novel papillomaviruses (PVs) were identified in urogenital swabs of 2 free-ranging female beluga whales in Bristol Bay, Alaska, USA. Their genomes were 7825 and 7713 nucleotides (nt) in length with 84.6% nt and 82.5% amino acid identities for the L1 gene, generally used for classifying papillomaviruses. Both PV genomes contained an early region of E6, E1, E2 and E4 genes, a late region containing L2 and L1 genes, and a non-coding regulatory region. The carboxy end of the E6 oncoprotein of both PVs did not contain the PDZ-binding motif, known to have a strong correlation with oncogenicity. BLAST NCBI nt analyses of the L1 gene of 1 PV revealed highest identity (91.2%) with a PV of a short-beaked common dolphin Delphinus delphis, while the other PV showed highest identity (85.5%) with a PV from a Yangtze River finless porpoise Neophocaena asiaeorientalis. The PVs identified in this study share the highest identity with PV members of the genus Upsilonpapillomavirus, subfamily Firstpapillomavirinae, family Papillomaviridae. Also, 2 herpesviruses were isolated in primary beluga whale kidney cell cultures and identified by sequencing the glycoprotein B and E genes. Both herpesviruses corresponded to the species Varicellovirus monodontidalpha1. Our findings confirm the necessity to expand studies on the occurrence, dissemination and virus diversity that may be adversely affecting the well-being and preservation of beluga whales in Alaska.
Tests of mirror self-recognition (MSR) have provided behavioral evidence of a high level of self-awareness in humans, chimpanzees, bonobos, orangutans, gorillas, bottlenose dolphins, Asian elephants, magpies, and to some extent in the cleaner wrasse. We conducted the standard mirror test with a social group of four beluga whales (Delphinapterus leucas), one subadult and three adult females, housed together at the New York Aquarium of the Wildlife Conservation Society. We exposed the whales to a two-way plexiglass mirror and a transparent control surface during baseline and post-mirror sessions and recorded and analyzed their behavioral responses in the three conditions. Two of the four whales, the subadult and her mother, exhibited a rich suite of self-directed behaviors at the mirror and subsequent mark and control sham-mark tests were conducted with both whales. The adult female showed mark-directed behavior at the mirror and passed one of the initial mark tests in a series of tests given. The self-directed behaviors exhibited by both whales and mark directed behavior by the adult female provides evidence for the capacity of MSR in the beluga whale.
The biosonar system of odontocetes enables directional sound transmission and reception. Beluga whales (Delphinapterus leucas) are notable among odontocetes as they can alter the shape of their fatty melon during sound transmission, potentially suggesting distinct acoustic capabilities. In this study, we developed a biosonar model of a beluga whale using computed tomography scanning and structural reconstruction to examine directional transmission and reception in this species. This model could modulate sounds into a directional beam using either single or dual sources. Across frequencies from 5 to 60 kHz, the directivity indices for the left and right sound sources ranged from 4.83 to 15.2 dB and 4.81-14.7 dB, respectively. When both sound sources were used simultaneously, there was an average increase of at least 2.26 dB in energy and 0.68 dB in the directivity index compared to using a single source. Additionally, beam steering was achieved in the dual-source transmission by introducing a timing difference between the two sources. The simulations indicated that sound reception was frequency-dependent, with the greatest sensitivity to lateral sounds at low frequencies and to forward sounds at high frequencies. These results suggested that both transmission and reception in beluga whales were directional and frequency-dependent.
This study evaluated the effectiveness of pH indicator patches in monitoring the quality of Beluga fish (Huso huso) stored at 4 °C for 3, 7, and 14 days, assessing changes in chemical, microbial, and sensory properties. Three polymer solutions (G0, G1, G2) were used to create nanofibrous patches via electrospinning. The fish were stored, and chemical analyses (peroxide value (PV) and total volatile basic nitrogen (TVB-N)), sensory evaluation (texture, color, odor), and microbial counts (psychrophilic and thermophilic bacteria) were conducted. On day 3, G0 and G1 exhibited clearer color changes compared to G2, with G1 showing sharper shifts. By day 14, G0 and G1 exhibited a slight decrease in the a* value, whereas G2 showed greater variation. PV and TVB-N increased significantly, indicating oxidative spoilage and protein degradation. Sensory evaluation revealed a decline in color, odor, texture, and acceptability. The pH-sensitive patches effectively monitored fish quality, but further optimization is needed.
As a result of their unique traditional diet, Inuit living in Nunavik (northern Quebec) exhibit among the highest blood concentrations of antioxidants selenoneine and ergothioneine worldwide. While beluga skin consumption has been identified as the main dietary source of selenoneine, potentially affording protection against methylmercury toxicity, little is known regarding the presence of ergothioneine, its sulphur isologue, in wild foods consumed by Inuit. We used isotope-dilution liquid chromatography-tandem mass spectrometry to quantify concentrations of selenoneine, ergothioneine and their metabolites in various organs and tissues obtained from 14 adult beluga whales (Delphinapterus leucas) harvested by Quaqtaq hunters in 2018-2019. We found the highest concentrations in the skin, with an average of 17.2 µg/g selenoneine and 78.6 µg/g ergothioneine - the highest ergothioneine concentration reported to date in the marine biome. We also obtained evidence of transplacental transfer of both antioxidants. Selenoneine and ergothioneine displayed outwardly increasing concentrations across skin layers and immunofluorescence staining revealed the primary location of the ergothioneine transporter in the basal epidermal layer. The combined accumulation of these antioxidants in the skin epidermis may suggest a protective role against UV photodamage and may help protect both belugas and Inuit against physical and chemical stressors of the northern environment.
The parameter values of neural networks will directly affect the performance of the network, so it is very important to choose the appropriate parameter tuning method to improve the performance of the neural network. In this paper, the improved beluga whale optimization hyperparameter optimization ResNet model is used to construct a new model, EBWO-ResNet. Firstly, in order to solve the problem that the initial population of the original beluga whale optimization is not rich enough, the Tent chaotic map is introduced into the beluga whale optimization, and a new algorithm EBWO is constructed. Secondly, in order to solve the problems of low accuracy and difficult parameter tuning of ResNet, the EBWO algorithm was integrated into ResNet to construct a new model EBWO-ResNet. Finally, in order to verify the effectiveness of the EBWO algorithm, the EBWO algorithm was applied to three engineering problems and compared with other five swarm intelligent algorithms, and in order to verify the effectiveness of the EBWO-ResNet model, EBWO-ResNet was applied to maize disease identification,in order to improve the accuracy of corn identification and ensure corn yield,and the other seven models were compared based on three evaluation indexes. The experimental results show that the EBWO algorithm provides the best solutions in the three engineering problems, and the EBWO-ResNet has the best performance in identifying maize diseases, with an accuracy of 96.3%,which is 0.2-1.5 percentage points higher than that of other models.
Automation of scene classification within artistic domains has become more prevalent due to the advent of deep learning. This study presented a new framework for classifying dance scenes using an adapted Squeeze-and-Excitation Network (SENet) and optimized hyperparameters with Advanced Beluga Whale Optimization Algorithm (ABWOA). The SENet architecture allows for redistributing features by adaptively focusing on the most discriminative visual features (e.g., posture, costume), and ABWOA efficiently optimizes hyper-parameters improve convergence and generalization. The framework has been evaluated on the Dance5K dataset that significantly outperformed the state-of-the-art models with an accuracy value of 92.6% and an F1-score value of 96.4%. Comprehensive experiments, including statistical significance tests, and cross validation validates the robustness of the framework. These results illustrate the potential of blending attention-based CNNs and bio-inspired optimization techniques within fine-grained visual categorization of cultural and artistic domains.
Respiratory infections are major health concerns in wild and managed cetaceans, yet reliable methods for assessing lower respiratory tract inflammation are limited. We aimed to evaluate the clinical utility of bronchoalveolar lavage fluid (BALF) neutrophil differentials in three managed bottlenose dolphins (Tursiops truncatus) and three managed beluga whales (Delphinapterus leucas) undergoing treatment for respiratory infections. Infection status was monitored by assessing isolated bacteria and fungi from BALF, BALF neutrophil differentials, and inflammatory markers in the blood, such as total leukocyte counts, plasma fibrinogen levels, and serum iron levels. In animals with respiratory bacterial and/or fungal infections alone, both BALF neutrophil differentials (47.3–55.7%) and blood inflammatory markers were elevated. Following antimicrobial treatment, the differentials decreased (0.8–3.8%), and blood inflammatory markers also returned to normal ranges. Contrastingly, in animals with concurrent conditions, such as respiratory bacterial and/or fungal infections accompanied by wounds on the tail fin or infection-induced iron deficiency anemia, persistent blood inflammatory markers were observed after antimicrobial treatment. Despite this, BALF neutrophil differentials, which are specific to respiratory inflammation, decreased in response to treatment (3.1–21.6%). Moreover, microorganisms isolated from blow samples from these animals were not consistent with those isolated from BALF at the same time. These findings suggest that BALF reflects localized respiratory infection more accurately than the inflammatory markers in the blood, and BALF examination is useful for diagnosing microbial infections in the lower respiratory tract in cetaceans. This approach may improve clinical decision-making and therapeutic outcomes in managed cetacean populations worldwide. The online version contains supplementary material available at 10.1007/s11259-026-11112-8.
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The proliferation of multimodal misinformation on social media has become a critical concern. Although detection methods have advanced, feature representation and cross-modal semantic alignment challenges continue to hinder the effective use of multimodal data. Therefore, this paper proposes an IBWO-CASC detection model that integrates an improved Beluga Whale Optimization algorithm with cross-modal attention feature fusion. Firstly, the Beluga Whale Optimization algorithm is enhanced by combining adaptive search mechanisms with batch parallel strategies in the feature space. Secondly, a feature alignment method is designed based on supervised contrastive learning to establish semantic consistency. Then, the model incorporates a Cross-modal Attention Promotion mechanism and global-local interaction learning pattern. Finally, a multi-task learning framework is built based on classification and contrastive objectives. The empirical analysis shows that the proposed IBWO-CASC model achieves a detection accuracy of 97.41% on our self-constructed multimodal misinformation dataset. Compared with the average accuracy of the existing six baseline models, the accuracy of this model is improved by 4.09%. Additionally, it demonstrates enhanced robustness in handling complex multimodal scenarios.
Changes in trophodynamics may affect trophic niche both at the individual and population levels. Using stable isotope ratios, we showed how contrasting oceanographic and trophic conditions in 1997-2003 and 2015-2020 have altered the diet and degree of individual specialization of St. Lawrence Estuary beluga (Delphinapterus leucas). The trophic niche of all sex and age classes changed over time, with beluga consuming more small pelagic prey during the first than the second period. Adult male diets differed from that of adult females and juveniles during the first period due to the other prey that were consumed. In 2015-2020, diet contributions by small pelagic prey decreased in all segments of the population and led to marginally significant differences in diet between adult males and females. These dietary changes were concomitant to a diversification of diet at the individual level and to an increase in diet heterogeneity among conspecifics and years within the 2015-2020 period. Whether these patterns emerged from an environment-driven reduction in prey biomass or from an increase in intra- and/or interspecific competition is unknown. Our findings illustrate the importance of considering individuals and not just the population when studying the foraging ecology of endangered species.
The current study aims to extract collagen from the skin of beluga sturgeon (Huso huso) using deep eutectic solvents combined with ultrasound as a green recovery method. It evaluates both the yield of the extraction process and the structural and physicochemical properties of the extracted collagen. The extraction utilized deep eutectic solvents, including choline chloride-glycerol, choline chloride-urea, and choline chloride-acetic acid, all at a molar ratio of 1:2. Among these, the choline chloride-acetic acid solvent yielded the highest extraction rate at 20.28 % and was selected for further ultrasound treatments lasting 5, 10, 15, and 20 min, with a power setting of 400 W. Ultrasound treatment significantly enhanced collagen extraction yield, with a 10-min treatment achieving the highest efficiency at 24 %. SDS-PAGE analysis confirmed the presence of type I collagen, indicating no structural changes during extraction. FTIR analysis showed that the triple helical structure of ultrasound-treated collagen was preserved throughout the process. Longer ultrasound treatment durations improved collagen purification, resulting in higher protein and total amino acid content. Additionally, ultrasound application enhanced thermal stability, water holding capacity, and gel formation power, with peak values observed during a 15-min treatment. In summary, extracting collagen from beluga skin using deep eutectic solvents in combination with ultrasound is an effective method for enhancing both yield and functionality of the resulting collagen.
Sign language (SL) is the linguistics of speech and hearing-impaired individuals. The hand gesture is the primary model employed in SL by speech and hearing-challenged people to talk with themselves and ordinary persons. At present, hand gesture detection plays a vital part, and it is commonly employed in numerous applications worldwide. Hand gesture detection systems can aid in transmission between machines and humans by aiding these sets of people. Machine learning (ML) is a subdivision of artificial intelligence (AI), which concentrates on the growth of a method. The main challenge in hand gesture detection is that machines do not directly understand human language. A standard medium is required to facilitate communication between humans and machines. Hand gesture recognition (GR) serves as this medium, enabling commands for computer interaction that specifically benefit hearing-impaired and elderly individuals. This study proposes a Gesture Recognition for Hearing Impaired People Using an Ensemble of Deep Learning Models with Improving Beluga Whale Optimization (GRHIP-EDLIBWO) model. The main intention of the GRHIP-EDLIBWO model framework for GR is to assist as a valuable tool for developing accessible communication systems for hearing-impaired individuals. To accomplish that, the GRHIP-EDLIBWO method initially performs image preprocessing using a Sobel filter (SF) to enhance edge detection and extract critical gesture features. For the feature extraction process, the squeeze-and-excitation capsule network (SE-CapsNet) effectively captures spatial hierarchies and complex relationships within gesture patterns. In addition, an ensemble of classification processes, such as bidirectional gated recurrent unit (BiGRU), Variational Autoencoder (VAE), and bidirectional long short-term memory (BiLSTM) technique, is employed. Finally, the improved beluga whale optimization (IBWO) method is implemented for the hyperparameter tuning of the three ensemble models. To achieve a robust classification result with the GRHIP-EDLIBWO approach, extensive simulations are conducted on an Indian SL (ISL) dataset. The performance validation of the GRHIP-EDLIBWO approach portrayed a superior accuracy value of 98.72% over existing models.