Ecology Of Marine Mammals Research Articles

C and N stable isotopes enlighten the trophic behaviour of the dugong (Dugong dugon)

The dugong (Dugong dugon), a large marine mammal herbivore of the Indo-Pacific, is vulnerable to extinction at a global scale due to a combination of human-related threats including habitat degradation. The species forages on seagrass habitats (marine phanerogams) and plays a key role in the functioning and sensitivity of these declining coastal ecosystems. The trophic behaviour and plasticity of dugong populations in response to extrinsic and intrinsic factors are therefore crucial features to both dugong and seagrass conservation. Yet, this knowledge remains limited to few visual observations and analyses of mouth, stomach or faecal contents of stranded individuals. We take advantage of a long-term monitoring of stranded individuals from the endangered New Caledonian population to depict features of dugongs’ trophic ecology from Carbon and Nitrogen stable isotopes. A total of 59 dugong skin samples were used to portrait the stable isotope niche of dugongs according to their sex and maturity. In light of previous work conducted in New Caledonia, a subset of these samples was used to model the trophic mix of dugong males and females. Our stable isotope mixing models used C and N isotope values of 10 taxa bbelonging to five divisions of metazoans, plants, and chromists. Our results represent the first estimate of the species dietary niche in the isotopic space. They suggest that the diet of dugong calves overlaps more with that of adult females (δ13C: − 6.38 ± 1.13 ‰; δ15N: 2.49 ± 1.10 ‰) than males (δ13C: − 5.92 ± 1.10 ‰; δ15N: 3.69 ± 1.28 ‰). Further, we highlight differences in the expected trophic mix of dugong adult males and females. From these, we formulate a sex-specific foraging behaviour hypothesis in dugongs, whereby lactating females could forage over smaller spatial ranges but more diverse food sources thanmales. The study emphasizes the importance of long-term stranding monitoring programs to study the ecology of marine mammals.. Finally, it depicts an ecological feature that may contribute to the sensitivity of vulnerable dugongs to ongoing changes on tropical coastal ecosystems.

Geographic and tissue-specific variations of the trace elements and trophic niches of three offshore cetaceans in Chinese waters

Systematical investigation on trace elements’ (TEs) distribution and trophic niches of cetaceans are essential to understand marine mammal ecology and environmental toxicology. Here, the concentrations of 10 TEs and isotopic values in six tissues of stranded Stenella attenuata (SA) and Kogia breviceps (KB) from the northern South China Sea (SCS) and Peponocephala electra (PE) from the East China Sea (ECS) were investigated. The TEs levels of the studied cetaceans were characterized by geo- and tissue-specific distributions. For SA and KB, most TEs levels were in the normal ranges, with low toxicological risk. For PE, several toxic TEs accumulated above the thresholds up to 892.80 μg/g of Hg and 335.24 μg/g of Cd, indicating that land-based anthropogenic pollution may be an ongoing threat to top predators in the ECS. The liver, spleen, and kidney are the main organs that accumulate toxic TEs, and there are strong positive, such as Se–Hg, correlations in several tissues. In particular, for PE with severe Hg and Cd exposure, tissue-specific distribution and correlations were more obvious. The results of stable carbon and nitrogen isotopes showed partly overlapped trophic niches of the three cetaceans, with similar calculated trophic levels in a narrow range of 4.29–4.43.

Characterization of a novel papillomavirus identified from a whale (Delphinapterus leucas) pharyngeal metagenomic library

Here, using viral metagenomic method, a novel whale papillomavirus (temporarily named wPV, GenBank accession number OP856597) was discovered in a whale (Delphinapterus leucas) pharyngeal metagenomic library. The complete genome size of wPV is 7179 bp, with GC content of 54.4% and a nucleotide composition of 23.4% A, 22.3% T, 28.4% G, and 25.9% C. The viral genome has a typical papillomavirus organization pattern, and five ORFs were predicted, including two late genes encoding L1 and L2, and three early genes encoding E1, E2, and E6. Pairwise sequence comparison and phylogenetic analysis based on the L1 gene sequence indicated that wPV may be a novel species within genus Dyodeltapapillomavirus. In addition, the E2 region of wPV was predicted to have a potential recombination event. The discovery of this novel papillomavirus increases our understanding of the viral ecology of marine mammals, providing insights into possible future infectious diseases.

Niche Partitioning Among Marine Mammals Inhabiting a Large Estuary as Revealed by Stable Isotopes of C, N, S, and O

Detailed knowledge on habitat use by marine mammals is critical to understand their role in the ecosystem. The stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) have been widely used to study the trophic ecology of marine mammals, but the stable isotope ratios of other elements such as sulfur (δ34S) and oxygen (δ18O) can better inform about habitat use in areas with strong salinity and redox gradients. The Río de la Plata estuary represents the largest freshwater runoff in the south-western Atlantic Ocean and supports a rich community of marine mammals. Here, we analyzed δ34S values in bone from seven marine mammal species inhabiting the estuary and the adjacent Atlantic Ocean, in order to complement previous isotopic data (δ13C, δ15N and δ18O) and compare their resolution as habitat tracers. As expected, δ34S and δ18O offered relevant insights into the characterization of the habitat used by marine mammals and allowed a better delineation of habitat partitioning between them. Bottlenose dolphins, South American sea lions and South American fur seals seem to be frequent users of the less saline areas of the estuary, whereas Burmeister´s porpoises, franciscana dolphins and false killer whales seemed to prefer the saltier marine waters close to the bottom. Fraser´s dolphins were the only inhabitants of true offshore waters. Our findings demonstrate how the integration of different stable isotope ratios can help disentangle fine habitat partitioning between marine mammals living in a complex ecosystem such as Río de la Plata.

Sulfur stable isotope ratios provide further insight into movements of the fin whale, an oceanic long-range migrant

Stable isotope ratios have proven a valuable tool to investigate marine mammal ecology, including diet, distribution, and migratory movements. While most studies have focused on δ15N and δ13C values, δ34S values have been little used because their pattern of variation and tissue dynamics remain unclear. We examined the sequential variation of δ15N, δ13C, and δ34S values along the baleen plates from fin whales occurring off West Iceland in summer. All baleen plates exhibited fluctuations along their growing axis. A significant synchronic correlation was found between δ15N and δ34S values, while the relation of these values to the δ13C value was highly variable and inconsistent. These results were similar to those obtained in previous studies of Greenland bowhead whales, although the pattern of the oscillations in fin whales showed an increase in values during winter, while those of bowhead whales showed a decrease. Although seasonal variations in food intake and the associated cycles of protein synthesis and catabolism may have played a role in such fluctuations and the observed differences between species, we suggest that the main driver for the δ34S fluctuations reflected in baleen plates is the variation of local baselines between winter and summer grounds. This suggests ample potential for using δ34S values to study migratory movements and destinations of marine megafauna, provided that the geographic variation in δ34S baselines is clarified.

A Physio-Logging Journey: Heart Rates of the Emperor Penguin and Blue Whale.

Physio-logging has the potential to explore the processes that underlie the dive behavior and ecology of marine mammals and seabirds, as well as evaluate their adaptability to environmental change and other stressors. Regulation of heart rate lies at the core of the physiological processes that determine dive capacity and performance. The bio-logging of heart rate in unrestrained animals diving at sea was infeasible, even unimaginable in the mid-1970s. To provide a historical perspective, I review my 40-year experience in the development of heart rate physio-loggers and the evolution of a digital electrocardiogram (ECG) recorder that is still in use today. I highlight documentation of the ECG and the interpretation of heart rate profiles in the largest of avian and mammalian divers, the emperor penguin and blue whale.

Analysis of the Gastro-Intestinal Tract of Marine Mammals: A Multidisciplinary Approach with a New Multi-Sieves Tool.

Simple SummaryCurrently procedures used to obtain samples from the gastro-intestinal tract (GIT) and protocols used to perform their respective analyses do not allow a multidisciplinary approach of this system. In fact, the investigations applied on the GIT, when performed singularly, could impair or limit the other analyses, because the currently procedures do not consider the needs of other disciplines. This means that the analyses to perform must be selected a priori, sacrificing the collection of other types of data and leads to the risk of losing important information, especially for wildlife species. To solve this conflict, we implement and standardize a new methodological approach to the GIT of marine mammals, which allow the collection of samples for different disciplines at the same time, performing the respective analyses, interpret and compare their results in a multidisciplinary way. The compatibility of multiple analyses allows the gaining of more information about the cause of death of stranded marine mammals and to enhance the knowledge of their biology and ecology.Organs and content of the gastro-intestinal tract (GIT) of marine mammals are relevant for a variety of investigations and provide data to researchers from different fields. Currently used protocols applied to the GIT for specific analysis limit the possibility to execute other investigations and important information could be lost. To ensure a proper sample collection and a multidisciplinary investigation of the GIT of marine mammals, a new multi-sieves tool and a specific protocol have been developed. This new device and approach allowed the simultaneous sampling of the GIT and its content for the main investigations concerned. The samples collected during these preliminary trials were suitable to perform all the different research procedures considered in this work. The obtained results show that with a few and easy procedural adjustments, a multidisciplinary sampling and evaluation of the GIT of marine mammals is possible. This will reduce the risk of losing important data aimed at understanding the cause of death of the animal, but also biology and ecology of marine mammals, and other important data for their conservation and habitats management.

Detection of foraging behavior from accelerometer data using U-Net type convolutional networks

Narwhal (Monodon monoceros) is one of the most elusive marine mammals, due to its isolated habitat in the Arctic region. Tagging is a technology that has the potential to explore the activities of this species, where behavioral information can be collected from instrumented individuals. This includes accelerometer data, diving and acoustic data as well as GPS positioning. An essential element in understanding the ecological role of toothed whales is to characterize their feeding behavior and estimate the amount of food consumption. Buzzes are sounds emitted by toothed whales that are related directly to the foraging behaviors. It is therefore of interest to measure or estimate the rate of buzzing to estimate prey intake. The main goal of this paper is to find a way to detect prey capture attempts directly from accelerometer data, and thus be able to estimate food consumption without the need for the more demanding acoustic data. We develop three automated buzz detection methods based on accelerometer and depth data solely. We use a dataset from five narwhals instrumented in East Greenland in 2018 to train, validate and test a logistic regression model and the state-of-the art machine learning algorithms random forest and deep learning, using the buzzes detected from acoustic data as the ground truth. The deep learning algorithm performed best among the tested methods. We conclude that reliable buzz detectors can be derived from high-frequency-sampling, back-mounted accelerometer tags, thus providing an alternative tool for studies of foraging ecology of marine mammals in their natural environments. We also compare buzz detection with certain movement patterns, such as sudden changes in acceleration (jerks), found in other marine mammal species for estimating prey capture. We find that narwhals do not seem to make big jerks when foraging and conclude that their hunting patterns in that respect might differ from other marine mammals.

Beyond genetic differences: epigenetic variation in common bottlenose dolphins Tursiops truncatus from contrasting marine ecosystems

Recent genetic and morphological studies have indicated an incipient ecological divergence between 2 ecotypes of common bottlenose dolphinTursiops truncatusin the Southwestern Atlantic. However, genetic variation is not the only molecular mechanism that alters the phenotype of these animals: epigenetics can also influence phenotypic plasticity, as well as the ecological adaptation and divergence of natural populations. Nevertheless, very little is known about the role that epigenetics plays in the population ecology of marine mammals. In this work, we tested whether there are differences in DNA methylation patterns between a coastal and an offshore ecotype of common bottlenose dolphin. Methylation patterns were analyzed using the methylation-sensitive amplified polymorphism technique on biopsy samples collected from animals of both ecotypes. We found consistent differences in DNA methylation patterns between coastal and offshore individuals. We also confirmed the genetic differences described in previous studies, indicating that the divergence between ecotypes has both genetic and epigenetic components. Our data show that it is possible to differentiate animals from the coastal and offshore ecotypes using DNA methylation markers, supporting the hypothesis that contrasting environments—which are decisive for the ecological divergence of these populations—lead to epigenetic modifications in common bottlenose dolphins.

Effects of intense storm events on dolphin occurrence and foraging behavior

As storms become increasingly intense and frequent due to climate change, we must better understand how they alter environmental conditions and impact species. However, storms are ephemeral and provide logistical challenges that prevent visual surveys commonly used to understand marine mammal ecology. Thus, relatively little is known about top predators’ responses to such environmental disturbances. In this study, we utilized passive acoustic monitoring to characterize the response of bottlenose dolphins to intense storms offshore Maryland, USA between 2015 and 2017. During and following four autumnal storms, dolphins were detected less frequently and for shorter periods of time. However, dolphins spent a significantly higher percentage of their encounters feeding after the storm than they did before or during. This change in foraging may have resulted from altered distributions and behavior of their prey species, which are prone to responding to environmental changes, such as varied sea surface temperatures caused by storms. It is increasingly vital to determine how these intense storms alter oceanography, prey movements, and the behavior of top predators.

Marine mammal ecology and health: finding common ground between conventional science and indigenous knowledge to track arctic ecosystem variability

Marine mammals respond to, and thereby reflect, changes in Arctic ecosystems that are important both to practitioners of conventional science (CS) and to holders of indigenous knowledge (IK). Although often seen as contrasting approaches to tracking ecosystem variability, when CS and IK are combined they can provide complementary and synergistic information. Despite exceptions, ecosystem-focused CS is often spatially broad and time shallow (1000 s km, decades) while IK is comparatively narrow spatially and time deep (10 s km, centuries). In addition, differences in how information is gathered, stored, applied and communicated can confound information integration from these two knowledge systems. Over the past four decades, research partnerships between CS practitioners and IK holders have provided novel insights to an Alaskan Arctic marine ecosystem in rapid transition. We identify insights from some of those projects, as they relate to changes in sea ice, oceanography, and more broadly to marine mammal ecology and health. From those insights and the protocols of existing community-based programs, we suggest that the strong seasonal cycle of Arctic environmental events should be leveraged as a shared framework to provide common ground for communication when developing projects related to marine mammal health and ecology. Adopting a shared temporal framework would foster joint CS–IK thinking and support the development of novel and nonlinear approaches to shared questions and concerns regarding marine mammals. The overarching goal is to extend the range and depth of a common understanding of marine mammal health and ecology during a period of rapid ecosystem alteration. The current focus on CS–IK co-production of knowledge and recent inclusion of marine mammals as essential variables in global ocean observatories makes this an opportune time to find common ground for understanding and adapting to the rapid changes now underway in Arctic marine ecosystems.

Historical Perspectives: The History and Future of Marine Mammal Ecology

Historical Perspectives: The History and Future of Marine Mammal Ecology

The ocean has music for those who ping AND listen

Sound is a key sense for animals in the ocean, including humans. The integration of passive and active acoustics in behavioral and ecosystem studies has revealed much about how ocean systems work. Here, I will discuss how the integration of echosounders with various passive acoustic approaches has contributed to our understanding to the biology and ecology of marine mammals. For example, explaining the habitat selection of beaked whales, the foraging ecology, behavior, and communication of spinner dolphins, and the ability of dolphin sonar to discriminate fish species. Careful integration of passive and active acoustics has also contributed to sonar signal design and processing approaches. A recent study of Risso’s dolphins using passive acoustic recording tags on the dolphins themselves and echosounders deployed from a ship and an underwater vehicle provided new insights into how these animals make foraging decisions, what information is available to them and when, and how changes in their prey over space and time affect their foraging behavior. The combination of passive and active acoustics is providing insight into the ecology and dynamics of predator and prey at the scale of the individual and the population.Sound is a key sense for animals in the ocean, including humans. The integration of passive and active acoustics in behavioral and ecosystem studies has revealed much about how ocean systems work. Here, I will discuss how the integration of echosounders with various passive acoustic approaches has contributed to our understanding to the biology and ecology of marine mammals. For example, explaining the habitat selection of beaked whales, the foraging ecology, behavior, and communication of spinner dolphins, and the ability of dolphin sonar to discriminate fish species. Careful integration of passive and active acoustics has also contributed to sonar signal design and processing approaches. A recent study of Risso’s dolphins using passive acoustic recording tags on the dolphins themselves and echosounders deployed from a ship and an underwater vehicle provided new insights into how these animals make foraging decisions, what information is available to them and when, and how changes in their prey over spac...

Projecting Marine Mammal Distribution in a Changing Climate

Climate-related shifts in marine mammal range and distribution have been observed in some populations; however, the nature and magnitude of future responses are uncertain in novel environments projected under climate change. This poses a challenge for agencies charged with management and conservation of these species. Specialized diets, restricted ranges, or reliance on specific substrates or sites (e.g., for pupping) make many marine mammal populations particularly vulnerable to climate change. High-latitude, predominantly ice-obligate, species have experienced some of the largest changes in habitat and distribution and these are expected to continue. Efforts to predict and project marine mammal distributions to date have emphasized data-driven statistical habitat models. These have proven successful for short time-scale (e.g., seasonal) management activities, but confidence that such relationships will hold for multi-decade projections and novel environments is limited. Recent advances in mechanistic modeling of marine mammals (i.e., models that rely on robust physiological and ecological principles expected to hold under climate change) may address this limitation. The success of such approaches rests on continued advances in marine mammal ecology, behavior, and physiology together with improved regional climate projections. The broad scope of this challenge suggests initial priorities be placed on vulnerable species or populations (those already experiencing declines or projected to undergo ecological shifts resulting from climate changes that are consistent across climate projections) and species or populations for which ample data already exist (with the hope that these may inform climate change sensitivities in less well observed species or populations elsewhere). The sustained monitoring networks, novel observations, and modeling advances required to more confidently project marine mammal distributions in a changing climate will ultimately benefit management decisions across time-scales, further promoting the resilience of marine mammal populations.

Large scale passive acoustic recording efforts improve our understanding of long term changes in marine mammal ecology and distribution

Collaborative efforts across a large number of scientists working throughout the Western Atlantic Ocean has led to sharing of passive acoustic data spanning over a decade. These data allow for a 24/7 lens to be cast providing a long term temporal understanding of species presence. This collaborative approach has allowed for unprecedented research focusing on long term patterns and changes in distribution and movements of baleen whales and odontocetes. Results from these data shows how baleen whales migration paths can be defined and changes in these paths can be detected over time. Additionally, they show that whales are present at times of the year and in regions that were not previously documented, particularly during winter months. Beaked whale composition within and between each shelf break canyon where recordings are available varies considerably, demonstrating latitudinal as well as regional gradients in species presence. The addition of ambient noise curves to this mix provides context and allows for the evaluation of anthropogenic noise. This long term big picture view of species presence and movements improves our capacity to infer whether observed changes are a result of ecological, climatological, or anthropogenic factors.

A fully coupled ecosystem model to predict the foraging ecology of apex predators in the California Current

MARINE ECOLOGY PROGRESS SERIES Mar Ecol Prog Ser Vol. 556: 273–285, 2016 doi: 10.3354/meps11849 Published September 8 A fully coupled ecosystem model to predict the foraging ecology of apex predators in the California Current J. Fiechter 1, *, L. A. Huckstadt 2 , K. A. Rose 3 , D. P. Costa 2 Institute of Marine Sciences, University of California Santa Cruz, 1156 High St, Santa Cruz, CA 95064, USA Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 1156 High St, Santa Cruz, CA 95064, USA Department of Oceanography and Coastal Sciences, Louisiana State University, 1002-Y Energy, Coast & Environment Building, Baton Rouge, LA 70803, USA ABSTRACT: Results from a fully coupled end-to-end ecosystem model for the California Current Large Marine Ecosystem are used to describe the impact of environmental variability and prey availability on the foraging ecology of its most abundant apex predator, the California sea lion Zalophus californianus. The ecosystem model consists of a biogeochemical submodel embedded in a regional ocean circulation submodel, both coupled with a multi-species individual-based sub- model for forage fish (sardine and anchovy) and California sea lions. Sardine and anchovy are explicitly represented in the model as they are commonly found in the diet of sea lions and exhibit significant interannual and decadal variability in population abundances that reflect variations in their environment and lower trophic level prey. Output from a 20 yr run (1989−2008) of the model demonstrates how different physical and biological processes control habitat utilization and forag- ing success of California sea lions on interannual time scales, with the dominant modes of variabil- ity linked to sardine abundance and coastal upwelling intensity. The results also illustrate how variability in environmental conditions, forage fish distribution, and prey assemblage affect sea lion feeding success. While specifically focusing on the foraging ecology of sea lions, the modeling framework has the ability to provide a more complete understanding of the physical and biologi- cal mechanisms impacting trophic interactions in the California Current, or other regions where similar fully coupled ecosystem models may be implemented. KEY WORDS: Ecosystem model · Foraging ecology · California Current · Upwelling · Sea lions · Marine predators · Zalophus californianus Resale or republication not permitted without written consent of the publisher Determining the relationships between environ- mental variability, prey field dynamics, and the foraging ecology of marine mammals and other apex predators has been an on-going research topic for several decades (Fiedler et al. 1998). However, re - cent pro gress in animal tagging has shed new light on the mechanisms through which changing environmental conditions may impact the habitat selection of pelagic predators (Block et al. 2011, Irvine et al. 2014). Such information is critical to identify the underlying physical and biological processes that control the foraging and migratory behavior of higher trophic level species (Weise et al. 2006, Bailey et al. 2009). Understanding the linkages among environmental variability, prey availability, and predator distribution should ulti- mately lead to a better characterization of biologi- cal ‘hot spots’ in the ocean and how these hot spots may respond to changing climate conditions (Pala- cios et al. 2006). *Corresponding author: fiechter@ucsc.edu © Inter-Research 2016 · www.int-res.com INTRODUCTION

The marine mammal microbiome: current knowledge and future directions

Marine mammals are globally significant because of their sensitivity to environmental change and threatened status, often serving as ‘ecosystem sentinels’. Disease is a major cause of marinemammal population decline and the role of the microbiome in disease has generated considerable interest. Recent research in humans has greatly enhanced our understanding of how the host-associated microbial community, the microbiome, affects host health. In this review, we provide an overview of the extent of the marine mammal microbiome with a focus on whole community characterisation using genomic methods. This research highlights the overlap in microbial communities between geographically distinct species and populations of marine mammals, suggesting tight links betweenmarinemammals and their microbial symbionts over millions of years of evolution. An understanding of these links in both healthy and compromised hosts is essential to identifying at-risk populations and making ecologically appropriate management decisions. We advocate further development of innovative sampling and analytic techniques that advance the field of microbial ecology of marine mammals. Recent investigations have highlighted the capacity of the microbiome to act strongly and significantly in maintaining host health with a vital role in disease manifestation and immune system function. Members of the microbial community can directly influence the progression of a disease via infection and also modulate the host’s own immune system regulation and response. Indeed thehost’smicrobial partners areessential to immunesystem function. Themicrobiome has been observed to be species-specific in a variety of vertebrate hosts and is influenced by host phylogeny, as a result ofmillionsof yearsof co-evolution.Marinemammals represent unique evolutionary lineages and investigations into their associated microbes will provide a deeper understanding of their ecology and evolution.

Community-Based Observations of Marine Mammal Occurrences in Groswater Bay, Labrador

Experienced observers from the community of Rigolet, Newfoundland and Labrador, recorded marine mammal observations at Rigolet on the coast of Labrador from July to September 2012. During this study, a total of nine species of marine mammals were documented. A daily average of 2.6 (range 1–5) marine mammal species were observed, with Harp Seals (Pagophilus groenlandicus) and Common Minke Whales (Balaenoptera acutorostrata) being the most common. The area is thought to be regionally important for Ringed Seal (Pusa hispida) whelping; however, Ringed Seals were not observed in large numbers. Beluga Whales (Delphinapterus leucas) were also reported anecdotally, but were less common than the other species, with the possible exception of the Harbour Porpoise (Phocoena phocoena). Labrador is experiencing significant industrial growth related to hydroelectric development and offshore oil and gas exploration. These data should aid environmental assessment and environmental effects monitoring and assist researchers in understanding regional marine mammal ecology, including species diversity, seasonal occurrence, and relative abundance.

ECOLOGIA ALIMENTAR EM MAMÍFEROS MARINHOS: TÉCNICAS DE ESTUDO

Marine mammals feed on a wide variety of preys from distinct trophic levels, occupying different niches in short and in long food chains. Studies on feeding ecology of marine mammals are important to understand their trophic relationships, as well as assessing their trophic levels in a food web. These investigations contribute for a better comprehension of trophic structure, energy flow and function of the marine ecosystems. The goal of this review is to present the main methods used in studies of trophic ecology of marine mammals, including requirements to their applications, information that can be generated, as well as their limitations. The more conventional method, also the older one, is the analysis of stomach contents and feces. The importance of this tool is to provide the prey species identification and the estimative of its biomass. These features turn this into a useful tool to be also used as baseline for the other methods. Recently, two methods have been raised involving stable isotope and fatty acid. Both techniques are based on the fact that the isotopic and the fatty acid signature of the consumer reflect those of its preys in a predictable way, which allows investigations on marine mammal foraging in temporal and geographical scales. However, both methods present some limitations characterized by the fact that they do not allow identification of the consumed species, as well as by the necessity of previous knowledge on prey fatty acid signature or isotopic ratio. In fact, none of the three methods answer all questions regarding feeding ecology and trophic relationships of marine mammal. They do constitute complementary tools that should be simultaneously used wherever possible. Besides, micropollutants concentrations and patterns may provide additional information regarding diet and feeding habits of marine mammals.

Listening to marine mammals at basin to local scales.

The successful use of SOSUS to track broad‐scale occurrence patterns in whale calls during the second half of the 20th century fostered the development of autonomous recorders that can be deployed virtually anywhere in the world ocean. Over the past decade, data from these recorders have provided dramatic insights to marine mammal ecology. Patterns of call reception have demonstrated the near year‐round occurrence of some baleen whale species in Arctic and Antarctic waters, a discovery that challenges long‐held assumptions about the phenology of seasonal migrations. Integration of year‐long calling records with physical oceanographic measures at mooring‐based ocean observatories provides a means to include large whales in ecosystem‐based models. The reception of anthropogenic sounds on nearly all recorders, whether deployed in coastal or remote areas, emphasizes the need to develop regional “soundscapes” based upon integrative sampling and analytical protocols. Examples from several long‐term research programs will be provided as the basis for the strong assertion that passive acoustic observation of marine mammals is a vital component of any ocean observing system. Opportunities for future collaborations and the challenges of data management and access will be discussed.