Social information is predicted to be most valuable when pursuing patchy, ephemeral resources. Such resource dynamics emerge from biophysical coupling in the pelagic ocean, suggesting links from physical forcing to resource distribution to consumers’ production of social information. We tested these hypothesized links using integrated observations of blue whale communication, distribution of their krill prey, and physical oceanographic forcing in their foraging habitat. Physical forcing modulated both prey availability and predator communication across nested temporal scales. Interannually, stronger upwelling led to greater krill abundance and elevated production of blue whales’ foraging-associated calls. At finer scale, episodic upwelling produced denser krill swarms and heightened production of foraging-associated calls. Blue whales’ widely propagating calls thus function as reliable social indicators of patch quality in their vast, dynamic pelagic habitat. These findings demonstrate that biophysical coupling in the ocean shapes predator communication and provide insight into the ecological drivers of social information use.

Successful harmful algal bloom (HAB) prediction and monitoring employs a variety of observational and research strategies. We add to the existing suite of tools for detecting toxigenic Pseudo-nitzschia diatoms by developing a novel digital PCR (dPCR) assay targeting a key gene of the domoic acid biosynthetic pathway, dabA. Sequence alignments and synthetic gene fragments of dabA genes from Pseudo-nitzschia australis, P. multiseries, P. multistriata, and P. seriata, along with the closely-related red-algal genes kabA and radA, were used to design a dPCR assay and assess its specificity. This dPCR assay was demonstrated to be specific for dabA and can quantify concentrations >1 copy µL-1 in a reaction. The biogeography of published dabA genes suggests that the assay may be useful globally for target species. When screening a culture collection of Pseudo-nitzschia isolated from coastal California, the dPCR assay detected dabA genes from three of the eleven species tested. In samples collected during field campaigns in 2022 off Santa Barbara, CA and in 2023 in Monterey Bay, CA during toxic HAB events, Pseudo-nitzschia dabA genes were only detected in Monterey Bay samples. While the dPCR assay does not capture all dabA diversity, it is specific and provides a targeted means to assess the genetic potential of a toxic HAB event by dominant and potent toxin-producing Pseudo-nitzschia species in coastal California. Because dabA expression is a key indicator of DA production, using the assay to quantify gene transcription could speed the acquisition of data needed to forecast HABs before toxin is detected.

There is growing interest in floating offshore wind turbine (FOWT) technology, where turbines are installed on floating structures anchored to the seabed, allowing wind energy development in areas unsuitable for traditional fixed-platform turbines. Responsible development requires monitoring the impact of FOWTs on marine wildlife, such as whales, throughout the operational lifecycle of the turbines. Distributed acoustic sensing (DAS)—a technology that transforms fiber-optic cables into vibration sensor arrays—has been demonstrated for acoustic monitoring of whales using seafloor telecommunications cables. However, no studies have yet evaluated DAS performance in dynamic, engineered environments, such as floating platforms or moving vessels with complex, dynamic strain loads, despite their relevance to FOWT settings. This study addresses that gap by deploying DAS aboard a boat in Monterey Bay, California, where a fiber-optic cable was lowered using a weighted and suspended mooring line, enabling vertical deployment. Humpback whale vocalizations were captured and identified in the DAS data, noise sources were identified, and DAS data were compared to audio captured by a standalone hydrophone attached to the mooring line and a nearby hydrophone on a cabled observatory. This study is unique in: (1) deploying DAS in a vertical deployment mode, where noise from turbulence, cable vibrations, and other sources posed additional challenges compared to seafloor DAS applications; (2) demonstrating DAS in a dynamic, nonstationary setup, which is uncommon for DAS interrogators typically used in more stable environments; and (3) leveraging looped sections of the cable to reduce the noise floor and mitigate the effects of excessive cable vibrations and strain. This research demonstrates DAS’s ability to capture whale vocalizations in challenging environments, highlighting its potential to enhance underwater acoustic monitoring, particularly in the context of renewable energy development in offshore environments.

Marine soundscapes are dominated by fish choruses, when many fish vocalize concurrently, often for mating purposes. Passive acoustic monitoring (PAM) allows us to analyze spatiotemporal patterns of fish chorusing, identifying breeding grounds, species distributions, and mating seasons. By integrating PAM with environmental data (temperature, salinity, etc.), we can assess the environmental drivers of fish chorusing. Through the Sanctuary Soundscape Monitoring project, we collected PAM data across nine sites in Monterey Bay (MBNMS), Chumash Heritage (CHNMS), and Channel Islands National Marine Sanctuaries (CINMS), each recording for ∼2 years for a cumulative 17.9 years. We identified: (1) WHO: five fish choruses, including plainfin midshipman, bocaccio rockfish, white seabass, and two unidentified species; (2) WHERE: spatial variation in chorus types and occurrence; (3) WHEN: predominantly nocturnal, seasonal chorusing aligned with reproductive cycles; and (4) DRIVERS: environmental variables associated with different water masses drive chorusing presence, and fish tended to chorus more during marine heatwaves. Through non-invasively listening to fish, we gain critical insights into their reproductive behavior and environmental drivers, to better inform effective management and conservation, particularly under changing environmental conditions.

Uncrewed Aerial Vehicles (UAVs) can be a cost-effective solution for capturing a comprehensive view of surface ocean phenomena to study marine population dynamics and ecology. UAVs have several advantages, such as quick deployment from shore, low operational costs, and the ability to be equipped with various sensors, including visual imaging systems and thermal imaging sensors. However, analyzing high-resolution images captured from UAVs can be challenging and time-consuming, especially when identifying small objects or anomalies. Therefore, we developed a method to quickly identify a diverse range of targets in UAV images. We will discuss our workflow for accelerating the analysis of high-resolution visual images captured from a Trinity F90+ Vertical Take-Off and Landing (VTOL) drone in near-shore habitats around the Monterey Bay region in California at approximately 60 meters altitude. Our approach uses a state-of-the-art self-distillation with knowledge (DINO) transformer foundation model and multi-scale, sliced object detection (SAHI) methods to locate a wide range of objects, from small to large, such as schools or individual jellyfish, flocks of birds, kelp forests or kelp fragments, small debris, occasional cetaceans, and pinnipeds. To make the data analysis more efficient, we create clusters of similar objects based on visual similarity, which can be quickly examined through a web-based interface. This approach eliminates the need for previously labeled objects to train a model, optimizing limited human resources. Our work demonstrates the useful application of state-of-the-art techniques to assist in the rapid analysis of images and how this can be used to develop a recognition system based upon machine-learning for the rapid detection and classification of UAV images. All of our work is freely available as open-source code.

Among tremendous biodiversity within the California Current Ecosystem (CCE) are gigantic mysticetes (baleen whales) that produce structured sequences of sound described as song. From six years of passive acoustic monitoring within the central CCE we measured seasonal and interannual variations in the occurrence of blue (Balaenoptera musculus), fin (Balaenoptera physalus), and humpback (Megaptera novaeangliae) whale song. Song detection during 11 months of the year defines its prevalence in this foraging habitat and its potential use in behavioral ecology research. Large interannual changes in song occurrence within and between species motivates examination of causality. Humpback whales uniquely exhibited continuous interannual increases, rising from 34% to 76% of days over six years, and we examine multiple hypotheses to explain this exceptional trend. Potential influences of physical factors on detectability - including masking and acoustic propagation - were not supported by analysis of wind data or modeling of acoustic transmission loss. Potential influences of changes in local population abundance, site fidelity, or migration timing were supported for two of the interannual increases in song detection, based on extensive local photo ID data (17,356 IDs of 2,407 individuals). Potential influences of changes in foraging ecology and efficiency were supported across all years by analyses of the abundance and composition of forage species. Following detrimental food web impacts of a major marine heatwave that peaked during the first year of the study, foraging conditions consistently improved for humpback whales in the context of their exceptional prey-switching capacity. Stable isotope data from humpback and blue whale biopsy samples are consistent with observed interannual variations in the regional abundance and composition of forage species. This study thus indicates that major interannual changes in detection of baleen whale song may reflect underlying variations in forage species availability driven by energetic variations in ecosystem state.

Endangered blue whales in the eastern North Pacific seasonally occupy essential foraging habitat in Monterey Bay National Marine Sanctuary (MBNMS) off central California. Acoustic vector sensing within MBNMS, together with biologging and ecosystem observations, is revealing blue whale movement ecology across a range of temporal scales. Over days to months, blue whales were observed to repeatedly track wind-driven upwelling plumes within which their essential prey—krill—form dense aggregations. Over the years, blue whales predominantly occupied shelf-slope habitats, however, exceptionally strong upwelling was associated with a shift to greater occupancy of offshore deep-water habitats. The strongest upwelling year exhibited higher abundances of krill and greater offshore reach of coastal upwelling plume habitat. At both time scales, these acoustically detected behavioral patterns within the regional blue whale population are consistent with behaviors of individual whales revealed by biologging. Supporting the recovery of endangered whale populations requires understanding where, when and how they live, and how risks from human activities intersect. Biologging and periodic visual monitoring are essential to understanding the spatiotemporal patterns of whale habitat occupancy and movement ecology, and these patterns can be resolved in greater detail and with greater persistence through continuous acoustic monitoring of highly soniferous species.

Marine passive acoustic monitoring (PAM) has produced petabytes of data that are used by researchers, resource managers, industry, and regulators to understand how marine animals use sound and the impacts of anthropogenic noise on species and ecosystems throughout the global ocean. These big data provide unprecedented opportunities to study underwater soundscapes but also enormous challenges to efficiently extract information. To address these challenges, the Sound Cooperative (SoundCoop) project built community-focused cyberinfrastructure to promote improved, scalable and sustainable processing and access of marine PAM data for management, science, industry and military applications. Driven by cross-institutional participation representing a diversity of data collection methods and conditions, SoundCoop established guidance for standardized processing of ocean sound level metrics using freeware software toolkits and developed core tools and processes that support open science. Four comparative analyses that connect PAM monitoring efforts and integrate non-acoustic data illustrate how interoperable sound level metrics support a more coherent and synoptic perspective on ocean soundscapes using methods that current and future PAM projects can leverage. Such a framework around PAM big data offers the opportunity to revolutionize large-scale marine ecology and oceanography in similar ways to other transformative approaches for understanding environmental patterns and processes at global scales.

Aim: The urgency for remote, reliable and scalable biodiversity monitoring amidst mounting human pressures on ecosystems has sparked worldwide interest in Passive Acoustic Monitoring (PAM), which can track life underwater and on land. However, we lack a unified methodology to report this sampling effort and a comprehensive overview of PAM coverage to gauge its potential as a global research and monitoring tool. To address this gap, we created the Worldwide Soundscapes project, a collaborative network and growing database comprising metadata from 416 datasets across all realms (terrestrial, marine, freshwater and subterranean). Location: Worldwide, 12,343 sites, all ecosystem types. Time Period: 1991 to present. Major Taxa Studied: All soniferous taxa. Methods: We synthesise sampling coverage across spatial, temporal and ecological scales using metadata describing sampling locations, deployment schedules, focal taxa and audio recording parameters. We explore global trends in biological, anthropogenic and geophysical sounds based on 168 selected recordings from 12 ecosystems across all realms. Results: Terrestrial sampling is spatially denser (46 sites per million square kilometre-Mkm(2)) than aquatic sampling (0.3 and 1.8 sites/Mkm(2) in oceans and fresh water) with only two subterranean datasets. Although diel and lunar cycles are well sampled across realms, only marine datasets (55%) comprehensively sample all seasons. Across the 12 ecosystems selected for exploring global acoustic trends, biological sounds showed contrasting diel patterns across ecosystems, declined with distance from the Equator, and were negatively correlated with anthropogenic sounds. Main Conclusions: PAM can inform macroecological studies as well as global conservation and phenology syntheses, but representation can be improved by expanding terrestrial taxonomic scope, sampling coverage in the high seas and subterranean ecosystems, and spatio-temporal replication in freshwater habitats. Overall, this worldwide PAM network holds promise to support cross-realm biodiversity research and monitoring efforts.

Passive acoustic monitoring (PAM) data collection has been growing exponentially, resulting in petabytes of data that document ocean soundscapes, how they change over time, and what animals use these ecosystems at varying timescales. Efficiently extracting this critical information and comparing it to other datasets in the context of ecosystem-based management is a Big Data challenge that traditional desktop processing methods cannot address. The curation, management, and dissemination of PAM datasets is another challenge in need of collaborative progress. To meet these exigencies, a multi-agency funded Sound Cooperative (SoundCoop) project is building community-focused, national cyberinfrastructure capability for PAM data to promote improved, scalable and sustainable accessibility and applications for management and science. Driven by partnerships and framed by four case studies, the SoundCoop has established guidance on the standardized processing of sound level metrics using free software toolkits and begun developing core cyberinfrastructure components that future PAM projects can leverage. U.S. and international scientists contributed PAM data collected across 10 long-term monitoring projects to operationalize the production of hybrid-millidecade spectra across a diversity of labs/instruments. Collectively, the contributed data demonstrate the value of standardized processing that enables the creation of comparable results from disparate monitoring efforts.

Social information is predicted to enhance the quality of animals’ migratory decisions in dynamic ecosystems, but the relative benefits of social information in the long-range movements of marine megafauna are unknown. In particular, whether and how migrants use nonlocal information gained through social communication at the large spatial scale of oceanic ecosystems remains unclear. Here we test hypotheses about the cues underlying timing of blue whales’ breeding migration in the Northeast Pacific via individual-based models parameterized by empirical behavioral data. Comparing emergent patterns from individual-based models to individual and population-level empirical metrics of migration timing, we find that individual whales likely rely on both personal and social sources of information about forage availability in deciding when to depart from their vast and dynamic foraging habitat and initiate breeding migration. Empirical patterns of migratory phenology can only be reproduced by models in which individuals use long-distance social information about conspecifics’ behavioral state, which is known to be encoded in the patterning of their widely propagating songs. Further, social communication improves pre-migration seasonal foraging performance by over 60% relative to asocial movement mechanisms. Our results suggest that long-range communication enhances the perceptual ranges of migrating whales beyond that of any individual, resulting in increased foraging performance and more collective migration timing. These findings indicate the value of nonlocal social information in an oceanic migrant and suggest the importance of long-distance acoustic communication in the collective migration of wide-ranging marine megafauna.

Background In ecosystems influenced by strong seasonal variation in insolation, the fitness of diverse taxa depends on seasonal movements to track resources along latitudinal or elevational gradients. Deep pelagic ecosystems, where sunlight is extremely limited, represent Earth's largest habitable space and yet ecosystem phenology and effective animal movement strategies in these systems are little understood. Sperm whales (Physeter macrocephalus) provide a valuable acoustic window into this world: the echolocation clicks they produce while foraging in the deep sea are the loudest known biological sounds on Earth and convey detailed information about their behavior. Methods We analyze seven years of continuous passive acoustic observations from the Central California Current System, using automated methods to identify both presence and demographic information from sperm whale echolocation clicks. By integrating empirical results with individual-level movement simulations, we test hypotheses about the movement strategies underlying sperm whales' long-distance movements in the Northeast Pacific. Results We detect foraging sperm whales of all demographic groups year-round in the Central California Current System, but also identify significant seasonality in frequency of presence. Among several previously hypothesized movement strategies for this population, empirical acoustic observations most closely match simulated results from a population undertaking a "seasonal resource-tracking migration", in which individuals move to track moderate seasonal-latitudinal variation in resource availability. Discussion Our findings provide evidence for seasonal movements in this cryptic top predator of the deep sea. We posit that these seasonal movements are likely driven by tracking of deep-sea resources, based on several lines of evidence: (1) seasonal-latitudinal patterns in foraging sperm whale detection across the Northeast Pacific; (2) lack of demographic variation in seasonality of presence; and (3) the match between simulations of seasonal resource-tracking migration and empirical results. We show that sperm whales likely track oceanographic seasonality in a manner similar to many surface ocean predators, but with dampened seasonal-latitudinal movement patterns. These findings shed light on the drivers of sperm whales' long-distance movements and the shrouded phenology of the deep-sea ecosystems in which they forage.

Abstract The collection of environmental DNA (eDNA) samples is often laborious, costly, and logistically difficult to accomplish at high frequency in remote locations and over large geographic areas. Here, we addressed those challenges by combining two robotic technologies: an uncrewed surface vessel (USV) fitted with an automated eDNA sample collection device to survey surface waters in the eastern North Pacific Ocean from Alameda, CA to Honolulu, HI. USV Surveyor SD 1200 (Saildrone) carrying the Environmental Sample Processor (ESP) collected 2‐L water samples by filtration followed by RNAlater preservation at regular intervals over a 4200‐km, 29‐day transit. Sixty samples (52 field and 8 controls) were acquired and used to estimate the concentration of specific genes and assess eukaryotic diversity via targeted qPCR and metabarcoding of the cytochrome oxidase subunit I (COI) gene, respectively. Comparisons of control samples revealed important considerations for interpreting results. Samples stored at ambient temperatures onboard Surveyor over the length of the voyage had less total recoverable DNA and specific target gene concentrations compared to the same material immediately flash‐frozen after collection and stored in a laboratory. In contrast, the biodiversity of the COI genes in those samples was similar regardless of sample age and storage condition. COI genes affiliated with 40 eukaryotic phyla were found in native samples collected during the voyage. The distribution and dominance of those phyla varied across different regions, with some taxa spanning large continuous stretches >2000 km, while others were only detected in a single sample. This work highlights the utility and potential of using USVs fitted with autonomous eDNA sample collection devices to improve ocean exploration and support large, basin‐scale, systematic biodiversity surveys. Results of this study also inform future technical considerations for using automated eDNA samplers to acquire material and store it over prolonged periods under prevailing environmental conditions.

The Persistent Smart Acoustic Profiler combines advanced technologies to create a lightweight ocean soundscape monitoring platform with infinite endurance and near real-time reporting capability. While ocean soundscapes are crucial for understanding marine ecosystems and the behaviors of marine animals, they are severely undersampled and poorly understood. Numerous sensing strategies are being employed to add to the body of knowledge on soundscapes, however it is often both challenging and expensive to collect data over extended periods, especially in difficult-to-reach locations. With a variety of sensing tools at their disposal, scientists can monitor marine life, assess the health of ecosystems, and develop approaches that mitigate the impacts of anthropogenic sound, ultimately promoting a better coexistence between human activities and marine wildlife. PSAP offers a unique approach to soundscape monitoring. With its unlimited endurance, global communication capability and streamlined onboard signal processing, PSAP can be deployed once and never recovered, providing an endless stream of valuable soundscape information to shore in near real time from remote oceanic locations around the globe.

In 2015, the largest recorded harmful algal bloom (HAB) occurred in the Northeast Pacific, causing nearly 100 million dollars in damages to fisheries and killing many protected marine mammals. Dominated by the toxic diatom Pseudo-nitzschia australis, this bloom produced high levels of the neurotoxin domoic acid (DA). Through molecular and transcriptional characterization of 52 near-weekly phytoplankton net-tow samples collected at a bloom hotspot in Monterey Bay, California, we identified active transcription of known DA biosynthesis (dab) genes from the three identified toxigenic species, including P. australis as the primary origin of toxicity. Elevated expression of silicon transporters (sit1) during the bloom supports the previously hypothesized role of dissolved silica (Si) exhaustion in contributing to bloom physiology and toxicity. We find that co-expression of the dabA and sit1 genes serves as a robust predictor of DA one week in advance, potentially enabling the forecasting of DA-producing HABs. We additionally present evidence that low levels of iron could have co-limited the diatom population along with low Si. Iron limitation represents a previously unrecognized driver of both toxin production and ecological success of the low iron adapted Pseudo-nitzschia genus during the 2015 bloom, and increasing pervasiveness of iron limitation may fuel the escalating magnitude and frequency of toxic Pseudo-nitzschia blooms globally. Our results advance understanding of bloom physiology underlying toxin production, bloom prediction, and the impact of global change on toxic blooms. Significance Pseudo-nitzschia diatoms form oceanic harmful algal blooms that threaten human health through production of the neurotoxin domoic acid (DA). DA biosynthetic gene expression is hypothesized to control DA production in the environment, yet what regulates expression of these genes is yet to be discovered. In this study, we uncovered expression of DA biosynthesis genes by multiple toxigenic Pseudo-nitzschia species during an economically impactful bloom along the North American West Coast, and identified genes that predict DA in advance of its production. We discovered that iron and silica co-limitation restrained the bloom and likely promoted toxin production. This work suggests that increasing iron limitation due to global change may play a previously unrecognized role in driving bloom frequency and toxicity.

This archive contains all data and code required to reproduce a study of baleen whale behavioral ecology. The archive includes

Earth’s largest animal species, blue and fin whales, share a similar life history strategy involving annual long-distance migration between foraging and breeding habitat. The difficulty of monitoring spatial distributions of both species simultaneously has limited understanding of their sympatry within foraging habitats that sustain them. In addressing this observational challenge, a valuable method is acoustic vector sensing of the sounds produced by the whales. Using three years of continuous acoustic vector sensor data, we examine habitat occupancy of blue and fin whales in the central California Current Ecosystem. While fin whales called almost exclusively from offshore deep-water habitat, blue whales called predominantly from shelf and slope water habitat—indicating an allopatric tendency. However, stronger sympatry occurred during the third year, as blue whales spent a greater proportion of time in offshore deep-water habitat. This year was distinguished by the strongest wind-driven coastal upwelling, the furthest offshore extension of upwelled waters, and the greatest abundances of krill that are prey of both whale species. upporting the recovery of endangered blue and fin whale populations requires understanding where and how they live, and acoustic vector sensing is effective for this purpose in ecological research and resource management.

Animals' ability to track variable resources in space and time is critical to their survival in dynamic and changing ecosystems. Understanding populations' behavioral flexibility in response to natural and anthropogenic ecosystem variation requires long-term and detailed measurements of both animal behavior and ecosystem properties. In a series of recent studies, we leverage blue whales' widely-propagating songs to understand their capacity to track ecosystem variability across episodic foraging and seasonal-to-interannual migration scales. By integrating individual and population-level study of singing blue whales, we first identify an acoustic signature of their population-level transition from foraging to migration. Applying this acoustic signature to a six-year study period, we find that blue whales flexibly time their transition to migration to track interannual variability in the phenology of their foraging habitat. Within the foraging season, we further track blue whale behavior via a directional acoustic vector sensor. Using this approach, we find that blue whales maximize access to aggregated prey patches by dynamically tracking fine-scale wind-driven upwelling plumes in space and time. Combined, these findings display blue whales' ability to track oceanographic variability across spatial and temporal scales and suggest mechanisms by which these predators individually and collectively sense their dynamic foraging habitat.

Ocean microbes are the foundation of marine food webs, regulating carbon cycling and ecosystem dynamics. How they proliferate, die, move, and interact is regulated by physical, chemical, and biological factors that are dynamic and challenging to quantify in the natural environment. A significant limitation in many marine field studies is the inability to continuously sample the ever-changing ocean environment over space and time. In this study, we integrated spatiotemporal and multi-omic sample collection in an intensive sampling effort of phytoplankton ecology in Monterey Bay, California during the spring of 2021. Sampling methods coupled: (1) manual shipboard CTD sampling, (2) autonomous sampling using a Long-Range Autonomous Underwater Vehicle (LRAUV) equipped with an Environmental Sampling Processor (ESP), and (3) high-resolution physical measurements by an autonomous vertical profiler (Wirewalker). Sampling occurred as upwelling waned alongside declining domoic acid (DA) and low abundances of toxigenic Pseudo-nitzschia . Conditions needed to spark a widespread and toxic Pseudo-nitzschia bloom were absent, yet low-level DA was driven by similar mechanisms to those causing elevated DA. Three DA biosynthetic intermediate molecules were reported in the environment for the first time. Both shipboard and ESP sampling approaches identified DA biosynthetic gene expression at frontal zones. DA and expression of dabA , the gene encoding the first committed step of DA biosynthesis, were higher in association with recently upwelled water that supplied nutrients for growth and DA biosynthesis. Detection of subtle variations in dab gene expression in response to environmental variation provide a window into the ecological dynamics underpinning major toxic events. Graphical Abstract

Synopsis Species ecology and life history patterns are often reflected in animal morphology. Blue whales are globally distributed, with distinct populations that feed in different productive coastal regions worldwide. Thus, they provide an opportunity to investigate how regional ecosystem characteristics may drive morphological differences within a species. Here, we compare physical and biological oceanography of three different blue whale foraging grounds: (1) Monterey Bay, California, USA; (2) the South Taranaki Bight (STB), Aotearoa New Zealand; and (3) the Corcovado Gulf, Chile. Additionally, we compare the morphology of blue whales from these regions using unoccupied aircraft imagery. Monterey Bay and the Corcovado Gulf are seasonally productive and support the migratory life history strategy of the Eastern North Pacific (ENP) and Chilean blue whale populations, respectively. In contrast, the New Zealand blue whale population remains in the less productive STB year-round. All three populations were indistinguishable in total body length. However, New Zealand blue whales were in significantly higher body condition despite lower regional productivity, potentially attributable to their non-migratory strategy that facilitates lower risk of spatiotemporal misalignment with more consistently available foraging opportunities. Alternatively, the migratory strategy of the ENP and Chilean populations may be successful when their presence on the foraging grounds temporally aligns with abundant prey availability. We document differences in skull and fluke morphology between populations, which may relate to different feeding behaviors adapted to region-specific prey and habitat characteristics. These morphological features may represent a trade-off between maneuverability for prey capture and efficient long-distance migration. As oceanographic patterns shift relative to long-term means under climate change, these blue whale populations may show different vulnerabilities due to differences in migratory phenology and feeding behavior between regions. Spanish abstract La ecología y patrones de historia de vida de las especies a menudo se reflejan en la morfología animal. Las ballenas azules están distribuidas globalmente, con poblaciones separadas que se alimentan en diferentes regiones costeras productivas de todo el mundo. Por lo tanto, brindan la oportunidad de investigar cómo las características regionales de los ecosistemas pueden impulsar diferencias morfológicas dentro de una especie. Aquí, comparamos la oceanografía física y biológica de tres zonas de alimentación diferentes de la ballena azul: (1) Bahía de Monterey, California, EE. UU., (2) Bahía del sur de Taranaki (BST), Nueva Zelanda, y (3) Golfo de Corcovado, Chile. Adicionalmente, comparamos la morfología de las ballenas azules de estas regiones utilizando imágenes de aeronaves no tripuladas. La Bahía de Monterey y el Golfo de Corcovado son estacionalmente productivos y apoyan la estrategia migratoria de la historia de vida de las poblaciones de ballena azul chilena y del Pacífico Norte Oriental (PNO), respectivamente. Por el contrario, la población de ballena azul de Nueva Zelanda permanece en la menos productiva BST durante todo el año. Las tres poblaciones eran indistinguibles en cuanto a la longitud corporal total. Sin embargo, las ballenas azules de Nueva Zelanda tenían una condición corporal significativamente mayor a pesar de una menor productividad regional, potencialmente atribuible a su estrategia no migratoria que facilita un menor riesgo de desalineación espaciotemporal con oportunidades de alimentación disponibles de manera más consistente. Alternativamente, la estrategia migratoria de las poblaciones de ballenas PNO y chilena puede tener éxito cuando su presencia en las zonas de alimentación se alinea temporalmente con la abundante disponibilidad de presas. Documentamos diferencias en la morfología del cráneo y la aleta caudal entre poblaciones, que pueden estar relacionadas con diferentes comportamientos de alimentación adaptados a las características de hábitat y presas específicas para cada región. Estas características morfológicas pueden representar una compensación entre la maniobrabilidad para la captura de presas y una migración eficiente a larga distancia. A medida que los patrones oceanográficos cambian en términos de mediano a largo plazo debido al cambio climático, estas poblaciones de ballenas azules pueden mostrar diferentes vulnerabilidades debido a diferencias en la fenología migratoria y el comportamiento de alimentación entre regiones.