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Fisheries constitute a major threat to marine mammals globally. To evaluate the impact of small-scale fisheries (SSF) on regional under-studied marine mammal populations, we tested a novel and cost-effective approach at three data-limited locations of the central and eastern Mediterranean Sea. Using off-the-shelf GPS loggers to track SSF activities and systematic surveys to map the distribution of marine mammals, we assessed the probability of co-occurrence between SSF and marine mammals by reporting areas of spatial overlap. Spatial overlap between SSF and the core zones of marine mammal distribution (ranging between 21.85–35.4%) was observed in all three locations, indicating potential interaction hotspots. The probability of co-occurrence in those areas varied from 0.5–2.9% depending on the species. The resulting overlap between fishing activity and marine mammals may pose a threat in both directions: higher risk of species entanglement and economic burden on fishers due to gear damage. Despite the spatial and temporal limitations of this pilot study, the proposed approach can provide baseline information on SSF-marine mammal co-occurrence, particularly in financially limited regions. If applied on a larger scale, our method may be used to inform future conservation actions with the aim to reduce pressure on key populations.

"Gaze following"—when one individual witnesses another shift its orientation, and then re-orients in the same direction—has been observed in a wide range of species. Related work with dolphins has to date focused on human–dolphin interactions. In this conspecific study, we examined a group of dolphins orienting, in passing, to gateways between their pools, as opportunities for witnesses to demonstrate "gaze following". Seven bottlenose dolphins were synchronously videotaped on six underwater cameras, for 21 h over three days, and the recordings analyzed by trained observers. The identities of all animals present, their partner state, and whether and to what degree they had altered their access to the gate (e.g., from Monocular to Binocular, or Binocular toVisio-Echoic) was recorded. Compared to animals that did not witness such a change, witnesses of an increase in access by another dolphin were significantly more likely to also act to increase their own access. We observed 460 such cases of "gaze following" in these animals. Dolphins who were partnered (showed sustained swimming within 1 body length) were significantly more likely, than non-partnered animals, to "gaze follow". Dolphins also showed a significant tendency toward matching the kind of access they observed. No significant difference was found in the presence of animals in the back pools, during changes in orientation that were followed, versus in those that were not. These findings support adding bottlenose dolphins to the growing list of species that display conspecific "gaze following".

Adult bottlenose dolphins share pectoral fin contacts (PFC) to manage their social relationships but less is known about how mothers share PFC with their calves. Using a dataset collected over 16 years, we analyzed how 10 matrilines, including three second generation female dolphins in a maternal role, used PFC with their pre-weaned calves. Mothers had different rates of initiation with their calves forming a continuum from those initiating few contacts (15%) to those initiating more (44%). For mothers with all-aged calves, the lateral side was contacted the most to start interactions with mothers contacting body parts at a similar rate. All mothers assumed the same posture regardless of their role as initiator or receiver, with horizontal the most prevalent posture. Two maternal styles were found for PFC: high and low use of PFC. Within the high PFC group, there was individual variation that was related to calf sex. Even though evidence of maternal style was confirmed in PFC exchanges between adult female dolphins and their calves, the number of PFC shared between these kin was only ~9% of all documented PFC contacts (N = 4,345) over 16 years, suggesting that other forms of tactile contact may be more important within the confines of the mother-offspring relationship in delphinids.

This study analyzed mtDNA sequences of two bottlenose dolphin subspecies found along the northern Patagonian coast, Argentina: the endangered Tursiops truncatus gephyreus and the data deficient Tursiops truncatus truncatus. Three haplotypes were recovered from nine samples. The most frequent haplotype represented the coastal morph, also two haplotypes showing falcate dorsal fin, a characteristic describing the oceanic morph. This finding suggests that both morphs may exist in sympatry in Argentina. Furthermore, sampling was extended beyond the species´ previously known range, including individuals as far as seven hundred kilometers to the south. Therefore, new genetic data, despite being preliminary, hint at an unexpectedly higher genetic diversity of matrilines than previously anticipated. Fil: Loizaga de Castro, Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Grandi, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Cunha, Haydée. Universidade do Estado de Rio do Janeiro; Brasil Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina

Passive acoustics are widely used to monitor the presence of dolphins in the marine environment. This study aims to introduce a low-cost and homemade approach for assembling a complete underwater microphone (i.e., the hydrophone), employing cheap and easy to obtain components. The hydrophone was assembled with two piezo disks connected in a balanced configuration and encased in a plastic container filled with plastic foam. The hydrophone’s performance was validated by direct comparison with the commercially available AS-1 hydrophone (Aquarian Hydrophones, Anacortes, U.S.) on different underwater acoustic signals: artificial acoustic signals (ramp and multitone signals) and various dolphin vocalizations (whistle, echolocation clicks, and burst pulse signals). The sensitivity of the device’s performance to changes in the emission source position was also tested. The results of the validation procedure on both artificial signals and real dolphin vocalizations showed that the significant cost savings associated with cheap technology had a minimal effect on the recording device’s performance within the frequency range of 0–35 kHz. At this stage of experimentation, the global cost of the hydrophone could be estimated at a few euros, making it extremely price competitive when compared to more expensive commercially available models. In the future, this effective and low-cost technology would allow for continuous monitoring of the presence of free-ranging dolphins, significantly lowering the total cost of autonomous monitoring systems. This would permit broadening the monitored areas and creating a network of recorders, thus improving the acquisition of data.

Cumulative exposure to sub-lethal anthropogenic stressors can affect the health and reproduction of coastal cetaceans and hence their population viability. To date, we do not have a clear understanding of the notion of health for cetaceans in an ecological context; that is, how health status affects the ability of individuals to survive and reproduce. Here, we make use of a unique health-monitoring programme of estuarine bottlenose dolphins in South Carolina and Florida to determine de novo changes in biological pathways, using untargeted plasma metabolomics, depending on the health status of individuals obtained from veterinary screening. We found that individuals that were in a poor health state had lower circulating amino acids pointing towards increased involvement of gluconeogenesis (i.e., new formation of glucose). More mechanistic work is needed to disentangle the interconnection between health and energy metabolism in cetaceans to mediate potential metabolic constraints they may face during periods of stress.

Bottlenose dolphins are the most common cetacean kept globally in zoos and aquaria (hereafter zoos), and are gregarious animals with a mostly opportunistic, generalist feeding strategy in the wild. In zoos, they have limited to no opportunities to express natural foraging behaviours as they receive their daily food ration of dead fish in a series of training sessions. Enrichment provision has increased in recent years, but items are still predominantly simple and floating in nature, and do not always target the animals’ problem-solving or food-acquisition behaviours. These discrepancies run concurrently with the intense debate about dolphin welfare in zoos and how to improve it. The current study used a within-subject design on 11 bottlenose dolphins at Kolmårdens Djurpark and measured how several welfare indicators differed between two treatments of “cognitive” and “non-cognitive” food-based enrichment. The treatments were provided on an alternating basis for eight consecutive weeks: during cognitive enrichment weeks, the animals received items which stimulated their problem-solving and foraging behaviours, and during non-cognitive enrichment weeks, they received simple items paired with fish (to eliminate bias due to food value). Data were taken related to several multidisciplinary welfare parameters during enrichment provision and training sessions, and to activity budget behaviours throughout the week. During the cognitive as opposed to non-cognitive enrichment weeks, the dolphins engaged more with the enrichment, were more motivated to participate in training sessions and performed less anticipatory and stereotypic behaviours, suggesting that cognitive enrichment improved several indicators of bottlenose dolphin welfare. Valuable lines of further investigation would be to understand how individual differences and different types of cognitive enrichment impact potential welfare benefits. Our results suggest that enrichment items promoting cognitive foraging behaviours may improve dolphin welfare, and therefore zoos might prioritise giving cognitive enrichment to this species as well as considering the same for other species with similar cognitive skills and foraging ecologies.

The few hormone studies on bottlenose dolphin (Tursiops truncatus) pregnancy with different reproductive outcomes, e.g., normal birth, stillbirth and abortion, have mostly focused on progestagens or relaxin. However, recent analysis of androgens, glucocorticoids and estrogens has shown they are also biomarkers of cetacean pregnancy. Therefore, our objective was to examine circulating concentrations of androgens, glucocorticoids and estrogens during bottlenose dolphin pregnancies with different reproductive outcomes, including normal pregnancy (NORM, n = 27), failure to thrive (FTT, n = 17), perinatal loss (PNL, n = 20), early loss (EL, n = 12) and false pregnancy (FP, n = 16), to determine if they could be potential indicators of reproductive or fetal health. We analyzed longitudinal serum samples (n = 654) from 57 bottlenose dolphins and 92 reproductive events for testosterone, androstenedione, cortisol, estradiol and estrone conjugates. Testosterone concentrations were higher during EL compared to NORM and lower during FP at MID (day 121 – 240 post ovulation/conception) and LATE (day 241 – end of FP) stages (months post conception/ovulation [MPC, MPO] seven through ten, P < 0.05). During FTT, androstenedione concentrations were increased compared to NORM pregnancies in the EARLY and LATE stages (P ≤ 0.05), and concentrations were reduced during FP (P < 0.05). For cortisol, FTT pregnancies had higher concentrations compared to NORM during all stages (P < 0.05), while PNL had higher cortisol during EARLY and LATE stages (P < 0.05). Estradiol concentrations were lower for EL and FP compared to NORM (P < 0.05), while estrone conjugates were only reduced during FP (P < 0.05). Based on our results only cortisol may be a useful predictor of PNL, while both cortisol and androstenedione were useful for distinguishing FTT pregnancies. Similarly, both testosterone and estradiol during EL and FP were different from NORM. Our data indicate a suite of pregnancy specific hormone biomarkers to evaluate maternal and fetal health in bottlenose dolphins should include cortisol, androgens and estrogens. This research also highlights the importance on non-progestagen hormones as sentinels of cetacean pregnancy and fetal health.

This study was conducted as part of a PhD thesis in the Graduate Programme in Ecology at the Federal University of Santa Catarina, with funding provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – 407190/2012-0) and Fundação de Amparo à Pesquisa e Inovação do Estado de Santa Catarina (FAPESC – TR2012000295). This study is also part of the SELA Long-Term Ecological Research Programme (PELD CNPq – 445301/2020-1). C.B. received a doctoral scholarship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); P.C.S.L. received a research grant from CNPq (305573/2013-6); F.G.D.J. received a research grant from CNPq (308867/2019-0). 1. The small population paradigm assumes that populations with low numbers of individuals intrinsically have a high probability of extinction. The small population of Lahille's bottlenose dolphins Tursiops truncatus gephyreus that specializes in foraging with artisanal fishers in Laguna, southern Brazil, faces human pressures including bycatch in fishing gear. The viability of this population was modelled over 30 and 100 years under different levels of bycatch, including the current scenario of two bycatches every year, two scenarios with higher incidence of bycatches and three management scenarios. The sensitivity of predicted growth rates to fixed-proportion and observed-variation changes in life history parameters was explored. 2. The current scenario predicted a declining population (r = -0.014; λ = 0.986) with a high probability of extinction in the long term (PE = 0.71). A small increase in bycatches would result in a marked increase in the probability of extinction. Management scenarios seem promising, but only the zero-bycatch management scenario would make the difference between a declining and an increasing population. 3. As expected for slow-growing species, population growth rate was most sensitive to proportional changes in adult female and juvenile survival. However, considering observed variation in vital rates, population dynamics were most influenced by variation in reproductive rates. 4. To determine the highest priority for management action, another simulation was made of how additional threat scenarios of recognized human activities (i.e. bycatch influencing adult survival and increased underwater noise or pollution influencing calf survival) would affect population dynamics. Population growth rate was very sensitive to changes in adult bycatch (especially females), as expected, and only subtly sensitive to a reduction in calf survival. 5. The current level of bycatch is unsustainable. Bycatch needs to be eliminated to maximize the probability of long-term persistence of this dolphin population. However, this population's persistence could be threatened by natural variation in reproductive rates. Postprint

Ecological monitoring allows to collect data and to gain knowledge on species or ecosystems. Thus, ecological monitoring is the basis on which biodiversity conservation is organized. Nowadays, the spatial scales of ecological monitoring and conservation issues diversify, as well as the increased complexity of institutional dynamics related to the collection of ecological data. In the French Mediterranean, a network of thirty Marine Protected Areas (MPA) is operating along the coastline. These MPA collect ecological data and work for the protection of marine biodiversity, each at its own scale and with its own means. For many issues related to the protection of marine biodiversity, the relevant ecological scale is that of the Mediterranean coastline embracing the entire MPA network around the same ecological context. This is the case for mobile species such as marine mammals.In this context, acquiring ecological knowledge at large spatial scales from data collected by a multitude of actors raises two major issues. First, an operational and policy challenge that consists in involving and coordinating institutions and stakeholders that collect ecological data. Second, a methodological challenge that lies in the ability to propose statistical tools that can produce robust ecological indicators from several monitoring protocols. During this thesis, I wanted to jointly study both of these two issues, operational and methodological, by setting up an interdisciplinary approach mobilizing social sciences and statistical ecology. The analysis is focused on the ecological monitoring of bottlenose dolphins (*Tursiops truncatus*) in the French Mediterranean Sea.By conducting semi-directive interviews with MPA managers in the French Mediterranean, I studied the place of ecological data in the functioning of MPA and in the working life of the MPA managers. The interviews and the collaboration with biodiversity managers also allowed to identify methodological requirements to support the ecological monitoring of bottlenose dolphins at the scale of the French Mediterranean MPA network. Thus, I developed integrated modeling tools allowing the joint analysis of multiple datasets to estimate the distribution, abundance and density of bottlenose dolphins at the scale of the French Mediterranean Sea.My work will have allowed i) to propose statistical tools relevant to the current context of the ecological monitoring of bottlenose dolphins in the French Mediterranean Sea, and ii) to highlight and describe the operational and political issues of coordinating ecological monitoring between the different MPA of the French Mediterranean Sea. Overall, my thesis is an illustration of the relevancy of the dialogue between social sciences and statistical ecology to produce ecologically effective and socially relevant conservation tools.; Les suivis écologiques permettent de collecter des données et d’acquérir des connaissances sur les espèces ou les écosystèmes. Les suivis écologiques constituent la base sur laquelle s’organise la gestion de la biodiversité. Aujourd’hui, ces suivis se font dans le contexte d’une diversification des échelles d’analyse des enjeux de conservation, et d’une complexification des dynamiques institutionnelles en lien avec la collecte de données écologiques. En Méditerranée française, une trentaine d’Aires Marines Protégées (AMP) forment un maillage de la façade maritime. Ces AMP collectent des données et œuvrent pour la protection de la biodiversité marine, chacune à son échelle et avec ses moyens. Pour de nombreux enjeux touchant à la protection de la biodiversité marine, l’échelle écologique pertinente est celle de la façade Méditerranéenne. C’est par exemple le cas pour les espèces mobiles comme les mammifères marins.Dans ce contexte, acquérir des connaissances écologiques à large échelle à partir de données collectées par une multitude d’acteurs soulèvent deux grands enjeux. Premièrement, un enjeu opérationnel et politique consiste à impliquer et coordonner les institutions et les acteurs qui collectent les données écologiques. Deuxièmement, un enjeu méthodologique réside dans la capacité à proposer des outils statistiques pouvant produire des indicateurs écologiques robustes à partir de plusieurs protocoles de suivis écologiques. Durant cette thèse, j’ai souhaité proposer l’étude simultanée de ces deux enjeux, opérationnel et méthodologique, en mettant en place une approche interdisciplinaire mobilisant sciences sociales et écologie statistique. L’analyse est centrée sur les suivis écologiques du grand dauphin (*Tursiops truncatus*) réalisés en Méditerranée française.En réalisant des entretiens semi-directifs avec les agents des AMP de Méditerranée française, j’ai développé une réflexion sur la place des données écologiques dans le fonctionnement des AMP et dans le quotidien des agents qui y travaillent. Les entretiens et la collaboration avec les professionnels de la biodiversité ont aussi permis d’identifier des besoins méthodologiques pour appuyer le suivi écologique du grand dauphin à l’échelle du réseau d’AMP de Méditerranée française. Ainsi, j’ai développé des outils de modélisation intégrée permettant l’analyse conjointe de plusieurs jeux de données pour estimer la distribution, les effectifs et la densité de grand dauphin à l’échelle de la Méditerranée française.Mon travail aura permis i) de proposer des outils statistiques adaptés au contexte actuel du suivi écologique du grand dauphin en Méditerranée française, et ii) de mettre en évidence et décrire les enjeux opérationnels et politiques de coordination des suivis écologiques entre les différentes AMP de Méditerranée française. Plus largement, ma thèse constitue une illustration de la pertinence du dialogue entre sciences sociales et écologie statistique pour produire des propositions d’outils de conservation écologiquement efficaces et socialement pertinents.

Ecosystems are experiencing elevated levels of disturbance, and species with narrower niches are often more vulnerable to disturbances. Niche breadth is often measured in terms of either diet or habitat use but diet and spatial use are infrequently considered in tandem. These different aspects of niche breadth potentially expose species to different types of disturbances; species with narrow dietary niches may be more affected by disturbances that alter trophic relationships, while species with narrow habitat niches may be more vulnerable to habitat loss and point‐source pollutants. We examined dietary and habitat niche breadth of common bottlenose dolphins, Tursiops truncatus truncatus, from three different nearshore sites in the Gulf of Mexico (GoM). Using stable isotopes, we determined proportional contributions of different prey groups to dolphin diets at each site and through time at one site. We used satellite‐linked telemetry at two sites to determine habitat use and site fidelity. Additionally, we examined the literature on cetacean diet, habitat use, movement, and IUCN status to determine relationships between niche breadth and population status for different species. Dolphin diets varied among sites as available prey varied, but Perciformes fish were the most frequently consumed prey. At the site for which we had temporal data, dolphins consumed more cephalopods in 2015 and 2018 but otherwise consumed primarily Perciformes fish. Dolphins had small utilization distributions and exhibited high site fidelity. Data from 31 cetacean species revealed that most species with vulnerable, threatened, or endangered IUCN statuses not only have specialized diets but also exhibit high site fidelity. Dolphins had diet characteristic of flexible generalists but were habitat specialists with high site fidelity. Dolphin populations in the GoM may have altered their diets in response to environmental changes that have altered community composition and trophic dynamics. On the other hand, their high site fidelity has exposed them to point‐source pollutants, such as oil spills, persistent organic pollutants, and freshwater. Our broader analysis of cetaceans confirmed that species with specialized diets and high site fidelity were the most vulnerable to disturbances, providing a framework to predict which nearshore dolphin populations, and cetaceans in general, are most vulnerable to environmental changes.

Passive acoustic monitoring (PAM) offers opportunities to collect data on the occurrence of vocal species for long periods of time, at multiple locations, and under a range of environmental conditions. Some species emit individually distinctive calls, including bottlenose dolphins (Tursiops truncatus) that produce signature whistles. Our study used PAM to determine the seasonal occurrence of bottlenose dolphins and utilized individually specific signature whistles to (1) track individuals spatially and temporally, (2) assess site fidelity off Maryland (MD), USA, (3) estimate the minimum abundance of dolphins in the study area, and (4) develop a dynamic habitat‐based relative abundance model applicable as a real‐time dolphin relative abundance prediction tool. Acoustic recorders were deployed at two sites offshore of Ocean City, MD, and at one site in the upper Chesapeake Bay, MD. Acoustic recordings from 2016 to 2018 were analyzed for signature whistles, and re‐occurrences of individual whistles were identified using a combination of machine learning and manual verification. A habitat‐based density model was created using the number of signature whistles combined with environmental conditions. A total of 1518 unique signature whistles were identified offshore of Maryland and in the upper Chesapeake Bay. There were 184 re‐occurrences of 142 whistles, with a mean of 135 d between re‐occurrences (range = 1–681 d). These repeated detections of the same individuals occurred most frequently at the site near Ocean City, MD, indicating the highest site fidelity. Re‐occurrences were recorded among all three sites, indicating movement of dolphins between the Chesapeake Bay and off the Atlantic coast of Maryland. The weekly number of individual dolphins detected off the Atlantic coast was significantly related to two environmental variables: sea surface temperature and chlorophyll a concentration. This habitat model could be used to predict relative dolphin abundance offshore of Maryland and inform management within the region, including in relation to offshore wind energy development and other stakeholders.

A major challenge in statistical ecology consists of integrating knowledge from different datasets to produce robust ecological indicators. To estimate species distribution, occupancy models are a flexible framework that can accommodate several datasets obtained from different sampling methods. However, repeating visits at sampling sites is a prerequisite for using standard occupancy models. Occupancy models were recently developed to analyze detection/non-detection data collected during a single visit. To date, single-visit occupancy models have never been used to integrate several different datasets. Here, we showcase an approach that combines two datasets into an integrated single-visit occupancy model. As a case study, we estimated the distribution of Bottlenose dolphins (Tursiops truncatus) over the North-western Mediterranean Sea by combining 24,624 km of aerial surveys and 21,464 km of at-sea monitoring. We compared the outputs of single- vs. repeated-visit occupancy models into integrated occupancy models. Integrated models allowed a better sampling coverage of species home-range, which provided a better precision for occupancy estimates than occupancy models using datasets in isolation. Overall, single- and repeated-visit integrated occupancy models produced similar inference about the distribution of bottlenose dolphins. We suggest that single-visit occupancy models open promising perspectives for the use of existing ecological datasets.

As demands for wildlife tourism increase, provisioning has become a popular means of providing up-close viewing to the public. At Monkey Mia, Shark Bay, Australia, up to five adult female Indo-Pacific bottlenose dolphins (Tursiops aduncus) visit a 100 m stretch of beach daily to receive fish handouts. In 2011, a severe marine heatwave (MHW) devastated seagrass and fish populations in Shark Bay. Offspring survival declined precipitously among seagrass specialists (dolphins that forage disproportionately in seagrass habitat). As all provisioned dolphins at the site are seagrass specialists, we examined how provisioned and non-provisioned seagrass specialists responded to the MHW. Using 27 years of data we compare habitat use, home range size, calf mortality, and predation risk between provisioned and non-provisioned females and their offspring before and after the MHW. Our results show that provisioned females have extremely small home ranges compared to non-provisioned females, a pattern attributable to their efforts to remain near the site of fish handouts. However, weaned offspring (juveniles) born to provisioned females who are not provisioned themselves also had much smaller home ranges, suggesting a persistent maternal effect on their behavior. After the MHW, adult females increased their use of seagrass habitats, but not their home range size. Provisioned females had significantly lower calf mortality than non-provisioned females, a pattern most evident pre-MHW, and, in the first 5 years after the MHW (peri-MHW, 2011–2015), calf mortality did not significantly increase for either group. However, the ecosystem did not recover, and post-MHW (2016–2020), calf mortality was substantially higher, regardless of provisioning status. With few survivors, the impact of the MHW on juvenile mortality post-weaning is not known. However, over three decades, juvenile mortality among offspring of provisioned vs. non-provisioned females did not statistically differ. Thus, the survival benefits accrued to calves in the provisioned group likely cease after weaning. Finally, although shark attack rates on seagrass specialists did not change over time, elevated predation on calves cannot be ruled out as a cause of death post-MHW. We discuss our results as they relate to anthropogenic influences on dolphin behavioral plasticity and responses to extreme climate events.

Identifying population structure and boundaries among communities of wildlife exposed to anthropogenic threats is key to successful conservation management. Previous studies on the demography, social and spatial structure of Indo-Pacific bottlenose dolphins (Tursiops aduncus) suggested four nearly discrete behavioral communities in Perth metropolitan waters, Western Australia. We investigated the genetic structure of these four communities using highly polymorphic microsatellite markers and part of the hypervariable segment of the mitochondrial control region. Overall, there was no evidence of spatial genetic structure. We found significant, yet very small genetic differentiation between some communities, most likely due to the presence of highly related individuals within these communities. Our findings of high levels of contemporary migration and highly related individuals among communities point toward a panmictic genetic population with continuous gene flow among each of the communities. In species with slow life histories and fission-fusion dynamics, such asTursiopsspp., genetic and socio-spatial structures may reflect different timescales. Thus, despite genetic similarity, each social community should be considered as a distinct ecological unit to be conserved because they are exposed to different anthropogenic threats and occur in different ecological habitats, social structure being as important as genetic information for immediate conservation management. The estuarine community, in particular, is highly vulnerable and appropriate conservation measures are needed in order to maintain its connectivity with the adjacent, semi-enclosed coastal communities.

Identifying threatened populations and quantifying their vulnerability is crucial for establishing priorities for conservation and providing robust information for decision-making. Lahille’s bottlenose dolphins have been long subjected to by-catch mortality in gillnet fisheries in coastal waters of southern Brazil, particularly in the Patos Lagoon estuary and adjacent coastal waters, where dolphins from three populations (or Management Units) show overlapping home ranges. In this study we used a stage-classified matrix population model to conduct a demographic analysis of the Patos Lagoon estuary’s population with life-history data estimated through an 8 years mark-recapture study. A population viability analysis was used to run a series of simulations where the risk was assessed under different by-catch scenarios, taking into account the effects of parameter uncertainty and stochasticity in the projections. In the absence of by-catch, we estimated that this dolphin population would growth at a rate of about 3% annually (95% CI: 1.2% - 5.8%). Under current by-catch rates, prognoses indicated high probabilities of viability over the next 60 yrs. These optimistic prognoses appear to be associated with the high survival of adult females. However, the eventual removal of very few mature females (one every year or two) would result in a prominent likelihood of decline from its current abundance at all pre-specified levels. The viability of the population would be substantially improved if the survival of juveniles/sub-adults could be increased. This may be achieved through the recently implemented dolphin protection area, which prohibits gillnet fisheries in the core area of this population. If the protection area reduces the entanglement rates of the most impacted life-stages (i.e. juvenile/sub-adult dolphins), there would be a substantial chance of the Patos Lagoon estuary’s dolphin population increasing above 20% of its current size, which is here proposed as conservation goal. If met, this goal has the potential to promote habitat quality, increase genetic diversity and connectivity with adjacent populations, enhancing the ability of bottlenose dolphins in southern Brazil to cope with environmental change and potential disease outbreaks.

In South Australia, discrete populations of bottlenose dolphins inhabit two large gulfs, where key threats and population estimates have been identified. Climate change, habitat disturbance (shipping and noise pollution), fishery interactions and epizootic events have been identified as the key threats facing these populations. The Population Consequences of Disturbance (PCoD) framework has been developed to understand how disturbances can influence population dynamics. I used population estimates combined with population specific bioenergetics models to undertake a PCoD assessment, comparing how the two populations respond to the identified regional threats. Populations were modeled over a five year period looking at the influence of each disturbance separately. As expected, extreme disturbance scenarios, in terms of frequency and intensity, had the biggest influence on population trends. However, the magnitude of the effect differed by population, with Spencer Gulf showing a 43% and Gulf St Vincent a 23% decline under high frequency and high impact epizootic scenarios. Epizootic events were seen to have the largest influence on population trends and reproductive parameters for both populations, followed by climate change. Modeling provides insights into how disturbances may affect different populations, and informs management to mitigate their potential effects while there is still time to act. Keywords: Bioenergetics, marine mammals, disturbances, bottlenose dolphins, Bayesian modelling, fecundity, population trends Article Impact Statement: Human induced disturbances impact coastal bottlenose dolphins with varying severity depending on the population and disturbance.

Significance Aging is a degradative process that varies among individuals. Due to limitations in defining and differentiating aging rates in human populations, understanding why some people appear to age slower than others has proven difficult. We analyzed 44 blood-based indices of health as candidate aging rate biomarkers collected over a 25-y period on a relevant, long-lived population of dolphins. Evidence of subsets of dolphins exhibiting slow and accelerated aging rates were detected, despite sharing the same environment, diet, and health care. Furthermore, some dolphin subsets were more likely to develop clinically relevant conditions, including anemia and immunosenescence. Our results support the notion that aging rates in long-lived mammals may be defined and provide insight into novel interventions to delay aging., While it is believed that humans age at different rates, a lack of robust longitudinal human studies using consensus biomarkers meant to capture aging rates has hindered an understanding of the degree to which individuals vary in their rates of aging. Because bottlenose dolphins are long-lived mammals that develop comorbidities of aging similar to humans, we analyzed data from a well-controlled, 25-y longitudinal cohort of 144 US Navy dolphins housed in the same oceanic environment. Our analysis focused on 44 clinically relevant hematologic and clinical chemistry measures recorded during routine blood draws throughout the dolphins’ lifetimes. Using stepwise regression and general linear models that accommodate correlations between measures obtained on individual dolphins, we demonstrate that, in a manner similar to humans, dolphins exhibit independent and linear age-related declines in four of these measures: hemoglobin, alkaline phosphatase, platelets, and lymphocytes. Using linear regressions and analyses of covariance with post hoc Tukey–Kramer tests to compare slopes (i.e., linear age-related rates) of our four aging rate biomarkers among 34 individual dolphins aging from 10 y to up to 40 y old, we could identify slow and accelerated agers and differentiate subgroups that were more or less likely to develop anemia and lymphopenia. This study successfully documents aging rate differences over the lifetime of long-lived individuals in a controlled environment. Our study suggests that nonenvironmental factors influencing aging rate biomarkers, including declining hemoglobin and anemia, may be targeted to delay the effects of aging in a compelling model of human biology.

Bottlenose dolphins (Tursiops truncatus) of the Bocas del Toro archipelago are targeted by the largest boat-based cetacean watching operation in Panama. Tourism is concentrated in Dolphin Bay, home to a population of resident dolphins. Previous studies have shown that tour boats elicit short-term changes in dolphin behavior and communication; however, the relationship of these responses to the local population’s biology and ecology is unclear. Studying the effects of tour boats on dolphin activity patterns and behavior can provide information about the biological significance of these responses. Here, we investigated the effects of tour boat activity on bottlenose dolphin activity patterns in Bocas del Toro, Panama over 10 weeks in 2014. Markov chain models were used to assess the effect of tour boats on dolphin behavioral transition probabilities in both control and impact scenarios. Effect of tour boat interactions was quantified by comparing transition probabilities of control and impact chains. Data were also used to construct dolphin activity budgets. Markov chain analysis revealed that in the presence of tour boats, dolphins were less likely to stay socializing and were more likely to begin traveling, and less likely to begin foraging while traveling. Additionally, activity budgets for foraging decreased and traveling increased as an effect of tour boat presence. These behavioral responses are likely to have energetic costs for individuals which may ultimately result in population-level impacts. Boat operator compliance with Panamanian whale watching regulations is urgently needed to minimize potential long-term impacts on this small, genetically distinct population and to ensure the future viability of the local tourism industry.

Levels of boat traffic in coastal seas have been steadily increasing in many parts of the world, introducing pressures on marine wildlife through disturbance. The appropriate management of human activities is important not only to preserve wildlife, but also for the local communities that depend on ecotourism for employment and their economy. This study presents further insight into bottlenose dolphin (Tursiops truncatus) responses to boats in New Quay Bay (West Wales) within the Cardigan Bay Special Area of Conservation. This region is heavily dependent on wildlife tourism, and marine traffic is regulated through a long-standing Code of Conduct. Based on a long-term dataset spanning the months of April to October and the years 2010–2018, the study found that compliance to a code of human behaviour increased dolphin positive responses towards boats. Dolphin responses to individual named boats and to different boat types were examined in greater detail. Speed boats, small motorboats, and kayaks were found to break the code most often, resulting in higher rates of negative response by dolphins. Visitor passenger boats formed the majority of boat traffic in the area, and showed greater compliance than other general recreational crafts. Suggestions are made for the better protection of the coastal dolphin population, as well as the role that citizen science can play to help achieve this goal through working directly with wildlife trip boats and the recruitment of local observers.

M.N. was funded by a Crawford‐Hayes studentship and National Parks and Wildlife Service (NPWS), Department of Culture, Heritage and Gaeltacht, Ireland. E.D. was supported by the Beaufort Marine Research Award in Fish Population Genetics funded by the Irish Government under the Sea Change Programme. Financial support for A.D.F. was provided by the Welsh Government and Higher Education Funding Council for Wales through the Sêr Cymru National Research Network for Low Carbon, Energy and Environment, and from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska‐Curie grant agreement No. 663830. The functioning of marine protected areas (MPAs) designated for marine megafauna has been criticized due to the high mobility and dispersal potential of these taxa. However, dispersal within a network of small MPAs can be beneficial as connectivity can result in increased effective population size, maintain genetic diversity, and increase robustness to ecological and environmental changes making populations less susceptible to stochastic genetic and demographic effects (i.e., Allee effect). Here, we use both genetic and photo-identification methods to quantify gene flow and demographic dispersal between MPAs of a highly mobile marine mammal, the bottlenose dolphin Tursiops truncatus. We identify three populations in the waters of western Ireland, two of which have largely nonoverlapping core coastal home ranges and are each strongly spatially associated with specific MPAs. We find high site fidelity of individuals within each of these two coastal populations to their respective MPA. We also find low levels of demographic dispersal between the populations, but it remains unclear whether any new gametes are exchanged between populations through these migrants (genetic dispersal). The population sampled in the Shannon Estuary has a low estimated effective population size and appears to be genetically isolated. The second coastal population, sampled outside of the Shannon, may be demographically and genetically connected to other coastal subpopulations around the coastal waters of the UK. We therefore recommend that the methods applied here should be used on a broader geographically sampled dataset to better assess this connectivity. Publisher PDF

The non-lethal impacts of marine vessels on cetaceans are now a globally recognised threat. This study is the first to investigate the effect of marine traffic on the behaviour of bottlenose dolphins Tursiops truncatus in the Istanbul Strait, Turkey. The Istanbul Strait (also known as the Bosphorus) is one of the busiest international waterways in the world and is exposed to dense marine traffic. The effect of marine traffic, location and season on the behavioural transitions was investigated through general log-linear analysis. Further, the changes on the behavioural budget and bout duration were assessed using Markov chains. Results showed that marine vessels were the main driving force for the behavioural transitions. These changes in transitions between behaviours led to significant changes in behavioural budget and bout durations (average time in each behavioural state). Surface-feeding, resting and socialising behaviour significantly de creased in the control budget, while diving showed an increase in the presence of vessels. Moreover, dolphins spent less time surface-feeding, resting, socialising and diving once disrupted. Furthermore, the current level of vessel-dolphin interaction (51%) in the Istanbul Strait was sufficiently high to alter the dolphins' cumulative behavioural budget significantly. Finally, speed and distance of vessels played a considerable role in the directional responses of dolphins. These results raise concerns on the potential biological consequences of the observed behavioural changes, considering that the population is already classified 'at risk' and is still lacking species-specific conservation plans. The results of the study must be considered immediately to create protected zones in order to mitigate the vessel-dolphin interactions. © The authors 2017.

Este artículo contiene 10 páginas, 4 figuras, 1 tabla., 1. The Strait of Gibraltar is an important habitat for cetaceans due to its high marine productivity. However, it is also the second most navigated channel in the world, subjecting cetaceans to a high level of vessel traffic, including an established whale-watching fleet. Both maritime traffic and whale-watching activities have been shown to impact the behaviour of cetaceans, but little is known about their impact on the demography and dynamics of cetacean populations. 2. The aim of this study was to evaluate the impacts of both ferry traffic and whalewatching vessels on the apparent survival probability of a bottlenose dolphin (Tursiops truncatus) population that occurs in the Strait. 3. A Bayesian hierarchical mark–recapture modelling approach was applied to 8 years of photo-identification data (2002–2009). Apparent annual survival probability was negatively correlated with ferry traffic, which explained >70% of temporal variation in survival, in contrast to whale-watching, the effect of which was almost negligible. Despite these results, other natural and human-related factors are likely to drive apparent survival in the study area. 4. Abundance increased between 2002 and 2005, and then decreased between 2006 and 2009, while local per-capita recruitment decreased from 2004 until the end of the study period. These shifts correlated temporally with the construction of a large harbour on the Moroccan coast, which increased maritime traffic significantly, including a 40% increase in ferry traffic that regularly transited the Strait. 5. These results highlight the need to better understand the impact of maritime traffic on the demography of the dolphin population in the Strait, in order to implement evidence-based conservation regulations in a region of high cetacean occurrence., Funds were partially provided by the Spanish Ministry of Economy and Innovation (ref. CGL2009-08298), Loro Parque Foundation, CEPSA, the Spanish Ministry of the Environment, Fundación Biodiversidad and two EU LIFE programme grants (ref. LIFE07NAT/E/000732 and LIFE02NAT/E/8610). R. de Stephanis was supported by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa SEV2012-0262; Juan de la Cierva programme).

Animal acoustic behavior systems are complex and the lifestyle of marine mammals makes understanding these systems difficult as they spend much time submerged underwater and are often difficult to observe visually. Using passive acoustic monitoring to record and interpret cetacean vocalizations provides insights into how these animals use different vocalizations in various contexts. This thesis investigates the use of acoustic signals in foraging and communication in two wild delphinid species, the short-finned pilot whale and the bottlenose dolphin using animal attached digital recording devices (DTAG). In chapter 2, bottlenose dolphin clicks were recorded in Sarasota Bay, Florida to document click production rates among three behavioral contexts for application in density estimations. In chapter 3, bottlenose dolphin signature whistles were identified using the SIGID method to document temporal variations in signature whistle production. Combined application of passive acoustic monitoring with mark-recapture methods proved feasible with information on temporal variations in signature whistle production. In chapter 4, short-finned pilot whale buzzes were defined based on a maximum inter-click interval. Furthermore, the relationship of pilot whale buzzes and whistles with depth was investigated. A buzz duration, number of buzz clicks, whistle output, duration and energy flux density significantly decreased with increasing dive depths. In chapter 5, three buzz types produced by pilot whales were categorized. Analysis of the acoustic events occurring after each buzz showed that different buzz types are used for different biosonar tactics in foraging or communication. Gulps were investigated to identify potential cues for foraging success. The acoustic repertoire of delphinids is highly complex and the research in this thesis documents the variability in whistle and click production in bottlenose dolphins and pilot whales, which is fundamental to understand how passive acoustic monitoring can be used for interpreting delphinid behavior and documenting presence and location of animals.

Bottlenose dolphins (Tursiops truncatus) of the Bocas del Toro archipelago are targeted by the largest boat-based cetacean watching operation in Panama. Tourism is concentrated in Dolphin Bay, home to a population of resident dolphins. Previous studies have shown that tour boats elicit short-term changes in dolphin behavior and communication; however, the relationship of these responses to the local population’s biology and ecology is unclear. Studying the effects of tour boats on dolphin activity patterns and behavior can provide information about the biological significance of these responses. Here, we investigated the effects of tour boat activity on bottlenose dolphin activity patterns in Bocas del Toro, Panama over 10 weeks in 2014. Markov chain models were used to assess the effect of tour boats on dolphin behavioral transition probabilities in both control and impact scenarios. Effect of tour boat interactions was quantified by comparing transition probabilities of control and impact chains. Data were also used to construct dolphin activity budgets. Markov chain analysis revealed that in the presence of tour boats, dolphins were less likely to stay socializing and were more likely to begin traveling, and less likely to begin foraging while traveling. Additionally, activity budgets for foraging decreased and traveling increased as an effect of tour boat presence. These behavioral responses are likely to have energetic costs for individuals which may ultimately result in population-level impacts. Boat operator compliance with Panamanian whale watching regulations is urgently needed to minimize potential long-term impacts on this small, genetically distinct population and to ensure the future viability of the local tourism industry.

Funding: Fyssen post-doctoral fellowship, Fondation Total, a bridge funding from the School of Biology of the University of St Andrews and People’s Trust for Endangered Species (ML). 1. Protecting species often involves the designation of protected areas, wherein suitable management strategies are applied either at the taxon or ecosystem level. Special Areas of Conservation (SACs) have been created in European waters under the Habitats Directive to protect bottlenose dolphins, Tursiops truncatus, which forms two ecotypes, pelagic and coastal. 2. The SACs have been designated in coastal waters based on photo‐identification studies that have indicated that bottlenose dolphins have relatively high site fidelity. However, individuals can carry out long‐distance movements, which suggests potential for demographic connectivity between the SACs as well as with other areas. 3. Connectivity can be studied using genetic markers. Previous studies on the species in this area used different sets of genetic markers and therefore inference on the fine‐scale population structure and demographic connectivity has not yet been made at a large scale. A common set of microsatellite markers was used in this study to provide the first comprehensive estimate of genetic structure of bottlenose dolphins in European Atlantic waters. 4. As in previous studies, a high level of genetic differentiation was found between coastal and pelagic populations. Genetic structure was defined at an unprecedented fine‐scale level for coastal dolphins, leading to identification of five distinct coastal populations inhabiting the following areas: Shannon estuary, west coast of Ireland, English Channel, coastal Galicia, east coast of Scotland and Wales/west Scotland. Demographic connectivity was very low among most populations with

Welfare science has built its foundations on veterinary medicine and thus measures of health. Since bottlenose dolphins (Tursiops truncatus) tend to mask symptoms of poor health, management in captivity would benefit from advanced understanding on the links between health and behavioural parameters, and few studies exist on the topic. In this study, four representative behavioural and health measures were chosen: health status (as qualified by veterinarians), percentage of daily food eaten, occurrences of new rake marks (proxy measure of social activity), and willingness to participate (WtP) in Positive Reinforcement Training sessions as qualitatively measured by their caretakers. These data were collected multiple times a day, every day over the course of a year from a multi-facility, large sample size (ndolphins = 51), allowing powerful analyses of the relationships between measures. First, it was found that dolphins with a higher WtP score also had a significantly better health status, ate a higher percentage of their daily food, and a lower occurrence of new rake marks. In addition, the WtP score was significantly lower up to 3 days before the weekly veterinary diagnosis of a decrease in health state; the percentage of daily food eaten and new rake mark measures did not show any significant change before such a diagnosis. These results suggest that WtP in training sessions is a potential behavioural measure of dolphin welfare, and an indicator of early changes in the dolphins’ health state. We therefore suggest measurement of WtP as a more practical and non-invasive tool to support veterinary care and general management. More work needs to be conducted to elucidate the influence of social behaviour on health, and to identify other potential welfare indicators, but this long-term study has shown that qualitative measures can be both practical and valid when assessing dolphin welfare.

Homophilous behaviour plays a central role in the formation of human friendships. Individuals form social ties with others that show similar phenotypic traits, independently of relatedness. Evidence of such homophily can be found in bottlenose dolphins ( Tursiops aduncus ) in Shark Bay, Western Australia, where females that use marine sponges as foraging tools often associate with other females that use sponges. ‘Sponging’ is a socially learned, time-consuming behaviour, transmitted from mother to calf. Previous research illustrated a strong female bias in adopting this technique. The lower propensity for males to engage in sponging may be due to its incompatibility with adult male-specific behaviours, particularly the formation of multi-level alliances. However, the link between sponging and male behaviour has never been formally tested. Here, we show that male spongers associated significantly more often with other male spongers irrespective of their level of relatedness. Male spongers spent significantly more time foraging, and less time resting and travelling, than did male non-spongers. Interestingly, we found no difference in time spent socializing. Our study provides novel insights into the relationship between tool use and activity budgets of male dolphins, and indicates social homophily in the second-order alliance composition of tool-using bottlenose dolphins.

For humans, there is a well-established theory, which explains much of the variation in human verbal dyadic speech behavior, the “communication accommodation theory (CAT)”. In its most basic form, CAT predicts that as two conversation partners become more similar in their speech patterns, the more likely they are to perceive the interaction, and/or the other person favorably. In this exploration of CAT in a non-human mammal, I look for the cornerstones of the theory in bottlenose dolphin communication. Dolphins depend largely on acoustic communication to maintain ever-changing social interactions in a marine environment. Dolphins have individually specific signature whistles that allow them to broadcast their identity, and also are able to encode additional information across those whistle emissions. They often use these whistles in antiphonal exchanges with other dolphins. In Chapter 2, I show that dolphins use signature whistles more often when conspecifics are present, suggesting a socially mediated system for signature whistle use. I find that male allies do not converge their signature whistles from pre-alliance to alliance formation, as previously suggested, nor over the course of alliance (Chapter 3). I do find that allies have more similar signature whistles to their male partner than to non-allies and in Chapter 4, find that male allies subtly accommodate during antiphonal signature whistle exchanges. During experimental playbacks of manipulated whistles to a bottlenose dolphin, I recorded subtle parameter accommodation in the frequency pitch shifts from one unit of a signature whistle playback to the next, suggesting that even when there is no difference in reinforcement, dolphins have the propensity for accommodation during signature whistle interactions. This thesis presents the first suggestion that the CAT may be a good model for the study for animal communication systems moving forward. ""This work received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions" -- Funding

Welfare science has built its foundations on veterinary medicine and thus measures of health. Since bottlenose dolphins (Tursiops truncatus) tend to mask symptoms of poor health, management in captivity would benefit from advanced understanding on the links between health and behavioural parameters, and few studies exist on the topic. In this study, four representative behavioural and health measures were chosen: health status (as qualified by veterinarians), percentage of daily food eaten, occurrences of new rake marks (proxy measure of social activity), and willingness to participate (WtP) in Positive Reinforcement Training sessions as qualitatively measured by their caretakers. These data were collected multiple times a day, every day over the course of a year from a multi-facility, large sample size (ndolphins = 51), allowing powerful analyses of the relationships between measures. First, it was found that dolphins with a higher WtP score also had a significantly better health status, ate a higher percentage of their daily food, and a lower occurrence of new rake marks. In addition, the WtP score was significantly lower up to 3 days before the weekly veterinary diagnosis of a decrease in health state; the percentage of daily food eaten and new rake mark measures did not show any significant change before such a diagnosis. These results suggest that WtP in training sessions is a potential behavioural measure of dolphin welfare, and an indicator of early changes in the dolphins’ health state. We therefore suggest measurement of WtP as a more practical and non-invasive tool to support veterinary care and general management. More work needs to be conducted to elucidate the influence of social behaviour on health, and to identify other potential welfare indicators, but this long-term study has shown that qualitative measures can be both practical and valid when assessing dolphin welfare.

In comparison with terrestrial animals, such as primates, there is limited empirical evidence for cooperative behavior in marine mammals under experimental conditions. In this study, we used a cooperative rope-pulling task to investigate how bottlenose dolphins (Tursiops truncatus) coordinate their behavior with a partner. Dolphins successfully learned and were able to perform the task, even when one subject started after the other. In the no-delay condition (i.e., both subjects sent at the same time), one pair of dolphins showed coordinated behaviors. When pairs were successful in solving the task in the delay condition (i.e., one individual sent later than the other), the initiators (i.e., first individual sent) were likely to wait for the follower to arrive, and the follower was likely to swim faster when the initiator did not wait and started pulling the rope alone. These coordinated behaviors might help resolve the given cooperative task. Our results suggest that bottlenose dolphins learn to coordinate their behaviors via trial and error and recognize the necessity of performing simultaneous actions with a partner to successfully accomplish cooperative tasks. In addition, both partners showed behavioral changes over many trials of no-delay and delay conditions, suggesting that bidirectional coordination occurred in the cooperative task., ハンドウイルカがおたがいに協力しあうことを発見. 京都大学プレスリリース. 2019-10-25.

Bottlenose dolphins are large-brained social mammals residing in a fission-fusion society with relationships that are established and maintained over decades. We examined a decade-long data set of inter-individual pectoral fin contact exchanges to better understand how dolphins share information via tactile contact. Sex and age are significant factors in pectoral fin contact within non-kin dolphin dyads. Adult females shared more pectoral fin contacts with other adult females, while younger females showed no pattern of contact. Males shared more pectoral fin contacts with other males as juveniles and as adults, but showed no difference in the number of touches versus rubs as pectoral fin contacts with other males. Whether in the role of initiator as rubber or initiator as rubbee, male dolphins again preferred other males. These results support the notion that dolphins, especially male dolphins, might use pectoral fin contact as one tool in their repertoire for social bonding to establish, maintain and manage their inter-individual relationships. Additionally, it is also likely that the exchange of pectoral fin contact is developed and refined as individuals age, mature socially, and establish their place within a fission-fusion society.

Представлен обзор иностранной литературы, посвященный проблеме наиболее распространенных заболеваний дельфинов в океанариумах. В условиях неволи у дельфинов чаще всего диагностируют респираторные инфекции, пневмонии, язвы желудка, поражения кожи, опорно-двигательного аппарата, опухоли, попадание в организм инородных тел. Китообразные могут страдать от вирусных, бактериальных, грибковых инфекций и инвазий ленточными, круглыми червями и простейшими. Пневмонии часто сопровождаются образованием абсцессов и наличием плеврального выпота. Поражения кожи и опорно-двигательного аппарата чаще всего вызываются механическими травмами., The paper presents a review of foreign literature on the most common diseases of dolphins in seaquariums. Under conditions of captivity, dolphins are most often diagnosed with respiratory infections, pneumonia, stomach ulcers, skin lesions, the musculoskeletal system, tumors, as well as foreign bodies in a body. Cetaceans can suffer from viral, bacterial, fungal infections and invasions with tapeworms, roundworms, and protozoa. Often pneumonia is accompanied by the formation of abscesses and the presence of pleural effusion. Mechanical injuries most often cause lesions of the skin and musculoskeletal system., №1(79) (2019)

No abstract available.

Quantifying marine mammal abundance, site occupancy, and habitat use patterns is fundamental for the correct design and implementation of conservation and management schemes. Bottlenose dolphins in Irish waters form at least three distinct populations, two coastal and one pelagic, each ranging in different areas over unequal scales. While the abundance of all three has been estimated and core areas of use have been previously identified for the coastal populations, their habitat preferences have not yet been investigated sufficiently. In this thesis, generalised additive models were used to describe the habitat use of each population in relation to a suite of static and dynamic environmental parameters, over a range of temporal scales. Mixed models and generalised estimating equations were implemented to account for spatial and temporal autocorrelation when necessary. The habitat use of the pelagic population was modelled using two seasons (Summer and Winter) of aerial survey data of the greater part of the Irish EEZ and the models’ predictive capacity was tested on observations from two separate seasons. The interaction of environmental covariates with a habitat classifier was also tested to elucidate dolphin habitat use changes depending on whether they are in shelf, slope, or abyssal waters. The site occupancy of the coastal mobile population was modelled using five years of passive acoustic monitoring (C-POD) data from two locations on the west coast at an hourly, daily, and monthly scale. The second coastal population is resident in the outer Shannon estuary Special Area of Conservation and its abundance has been sporadically monitored for nearly two decades using boat-based photo-identification surveys. Encounter data from these surveys were used to model habitat use by incorporating a two-dimensional geographic coordinate term and an interaction with tidal phases. Given the irregular frequency of standardised surveys, I also assessed the potential of using a dolphin-watching boat operating in the same area as an alternative platform from which to derive a robust abundance estimate, using mark-recapture techniques. Different environmental covariates proved significant at each spatial scale, with dolphins showing season-, habitat-, and site-specific responses to each parameter. A higher probability of dolphin presence was predicted over the continental shelf and slope in the winter and in two primary areas in the summer, the southwest coast and the Porcupine Basin. Sea surface temperature and primary productivity were significant predictors of dolphin presence for both the pelagic and mobile coastal population, but not for the resident coastal population. Tidal level had a significant effect on dolphin detection in the coastal mobile population, with the likelihood of detections increasing at higher water levels. Tidal phase was also a significant predictor of dolphin presence for the resident population, with higher probabilities being predicted closer to a bottleneck feature during ebb tides. The abundance estimate generated from the dolphin-watching boat observations compared favourably to an estimate generated from a standardised survey the previous year. This indicates that, in years when standardised surveys do not take place, the dolphin-watching boat may provide a suitable interim platform for more frequent and efficient monitoring of this population. The results presented here highlight the importance of investigating habitat use at different spatial and temporal scales, provide valuable insights regarding areas used at different times by bottlenose dolphins, and form a baseline upon which to build further, more targeted investigations of the habitat preferences, demographic parameters, and abundance of each population, ultimately advancing our efforts at conservation and facilitating marine spatial planning.

In recent decades, a number of studies have examined whether various non-human animals understand their partner's role in cooperative situations. Yet the relatively tolerant timing requirements of these tasks make it theoretically possible for animals to succeed by using simple behavioural strategies rather than by jointly intended coordination. Here we investigated whether bottlenose dolphins could understand a cooperative partner's role by testing whether they could learn a button-pressing task requiring precise behavioural synchronization. Specifically, members of cooperative dyads were required to swim across a lagoon and each press their own underwater button simultaneously (within a 1 s time window), whether sent together or with a delay between partners of 1–20 s. We found that dolphins were able to work together with extreme precision even when they had to wait for their partner, and that their coordination improved over the course of the study, with the time between button presses in the latter trials averaging 370 ms. These findings show that bottlenose dolphins can learn to understand their partner's role in a cooperative situation, and suggest that the behavioural synchronization evident in wild dolphins' synchronous movement and coordinated alliance displays may be a generalized cognitive ability that can also be used to solve novel cooperative tasks.

Mercury (Hg) is a ubiquitous global contaminant with important public health implications. Mercury is released from a variety of anthropogenic, industrial processes, enters the earth's atmosphere and is re-deposited onto the earth’s surface in rainfall. Much of this Hg enters the oceans which cover the majority of the earth’s surface. In the marine environment, inorganic Hg is converted to the most toxic form of the element, methylmercury, and biomagnified through the trophic levels of the food web. The bottlenose dolphin (Tursiops truncatus) is the apex predator in many estuarine and coastal ecosystems. Due to their long life span and trophic position, bottlenose dolphins bioaccumulate high concentrations of contaminants including Hg, thus making them an important sentinel species for ecosystem and public health. Bottlenose dolphins in Florida bioaccumulate high concentrations of Hg in their blood, skin and internal organs. The concentrations of Hg in blood and skin of bottlenose dolphins of the Indian River Lagoon, FL (IRL) are among the highest reported world-wide. In previous studies, we demonstrated associations between concentrations of total Hg in the blood and skin of IRL dolphins and markers of endocrine, renal, hepatic, hematologic and immune system dysfunction. The predominant manifestation of exposure to mercury in humans is neurotoxicity. During the 1950s and 1960s, residents of Minamata bay, Japan were exposed to high concentrations of methyl mercury as the result of ingestion of fish and shellfish that had become contaminated in this infamous environmental disaster. Affected adults had severe motor and sensory abnormalities often leading to death. Methyl mercury crosses the placenta during pregnancy. Children exposed in utero were born with multiple congenital anomalies and also suffered from neurologic disorders. Significantly, local cats that consumed Hg contaminated fish developed severe signs of neurotoxicity which led to their subsequent description as the “dancing cats of Minamata bay”. Unfortunately, the cause of these strange manifestations in cats was not recognized in time to prevent hundreds of additional cases from occurring. More recent studies have shown that exposure to mercury as a result of seafood consumption during pregnancy may result in multiple cognitive and neurodevelopmental effects in children. The levels of mercury found in bottlenose dolphins and the health effects we identified alerted us to the possibility of an important public health hazard. The IRL occupies 40 percent of the east coast of Florida and is bordered by counties with approximately 2.5 million human inhabitants. Therefore, we hypothesized that local inhabitants in communities bordering the IRL could be at risk of exposure to Hg from the consumption of fish and shellfish. We measured hair Hg in 135 local residents and found a mean concentration of 1.53 µg/g which was higher than that from previous studies of sport fishermen and coastal residents in other states. Over 50% of participants had a hair Hg concentration which exceeded the U.S. EPA exposure guideline. Hair Hg concentration was directly related to the frequency of seafood consumption and to the proportion of fish and shellfish obtained from local recreational sources. This study clearly exemplifies the importance of an animal sentinel in identifying a public health hazard and is virtually unique in “closing the loop” between animal and human health.

Determining discrete and demographically independent management units within wildlife populations is critical for their effective management and conservation. However, there is a lack of consensus on the most appropriate criteria to delimit such management units. A multi-disciplinary, multi-scale approach that combines tools informing in the short-term (i.e. photo-identification), with mid-term ecological tracers (stable isotopes –δC, δN and δS– and persistent organic pollutants –POPs–), and mid- to long-term genetic markers (microsatellites and mitochondrial DNA), was used to define management units within bottlenose dolphins (Tursiops truncatus) inhabiting the southern Iberian Peninsula. Although genetically indistinguishable, individuals inhabiting the Strait of Gibraltar and the Gulf of Cadiz showed differences in their isotopic composition and the concentrations of certain POPs. Accordingly, the lack of photographic recaptures between the two sites pointed to the existence of at least two different ecological management units that segregate spatially and may require different conservation strategies. Different time-scale approaches can reveal different management units. The results highlighted the use of medium- and short-term approaches for properly identifying ecologically different units for effective management and conservation. Furthermore, these results have important management implications as European legislation promotes specific management plans for this species., This work was funded by Loro Parque Foundation, CEPSA, Ministerio de Medio Ambiente, Fundación Biodiversidad, LIFE+ Indemares [LIFE07NAT/E/000732], LIFE ‘Conservación de Cetáceos y tortugas de Murcia y Andalucía’ [LIFE02NAT/E/8610] and ECOCET project [CGL2011‐25543]. R.dS. and J.G. were supported by the Spanish Ministry of Economy and Competitiveness, through the Severo Ochoa Programme for Centres of Excellence in R+D+I [SEV‐2012‐0262], and also R.dS. by the ‘Subprograma Juan de la Cierva’.

International audience; Bottlenose dolphins () spontaneously emit individual acoustic signals that identify them to group members. We tested whether these cetaceans could learn artificial individual sound cues played underwater and whether they would generalize this learning to airborne sounds. Dolphins are thought to perceive only underwater sounds and their training depends largely on visual signals. We investigated the behavioral responses of seven dolphins in a group to learned human-made individual sound cues, played underwater and in the air. Dolphins recognized their own sound cue after hearing it underwater as they immediately moved toward the source, whereas when it was airborne they gazed more at the source of their own sound cue but did not approach it. We hypothesize that they perhaps detected modifications of the sound induced by air or were confused by the novelty of the situation, but nevertheless recognized they were being "targeted." They did not respond when hearing another group member's cue in either situation. This study provides further evidence that dolphins respond to individual-specific sounds and that these marine mammals possess some capacity for processing airborne acoustic signals.

Bottlenose dolphins (Tursiops truncatus) spontaneously emit individual acoustic signals that identify them to group members. We tested whether these cetaceans could learn artificial individual sound cues played underwater and whether they would generalize this learning to airborne sounds. Dolphins are thought to perceive only underwater sounds and their training depends largely on visual signals. We investigated the behavioral responses of seven dolphins in a group to learned human-made individual sound cues, played underwater and in the air. Dolphins recognized their own sound cue after hearing it underwater as they immediately moved toward the source, whereas when it was airborne they gazed more at the source of their own sound cue but did not approach it. We hypothesize that they perhaps detected modifications of the sound induced by air or were confused by the novelty of the situation, but nevertheless recognized they were being “targeted.” They did not respond when hearing another group member’s cue in either situation. This study provides further evidence that dolphins respond to individual-specific sounds and that these marine mammals possess some capacity for processing airborne acoustic signals.

Co-occurring species are expected to distribute themselves unevenly throughout ecological niche dimensions to avoid competitive exclusion. However, few studies have previously investigated spatial and trophic factors structuring an entire cetacean community. Here, we combined density surface models (DSMs) with two dimension (δN and δC) isotopic niche spaces in order to identify the mechanistic processes underlying niche partitioning for the most abundant cetacean species inhabiting the Alboran Sea: the long-finned pilot whale (Globicephala melas), the Cuvier's beaked whale (Ziphius cavirostris), the Risso's dolphin (Grampus griseus), the bottlenose dolphin (Tursiops truncatus), the striped dolphin (Stenella coeruleoalba), and the short-beaked common dolphin (Delphinus delphis). DSMs provide a spatially-explicit assessment of species distribution through key spatial and environmental gradients, whereas isotopic niches characterize habitat and resource use. Our isotopic niche approach pointed to habitat and/or trophic segregation between the small (striped and short-beaked common dolphins) and large-sized cetacean species (Risso's and bottlenose dolphins, and long-finned pilot whales). Conversely, DSMs suggested a larger degree of spatial segregation among species by depth, with some overlap for offshore species (long-finned pilot, Cuvier's beaked whales and Risso's dolphins) and also between bottlenose and common dolphins. Thus, both components of the ecological niche apparently played an important role in explaining niche partitioning among species, which, in turn, might explain the high abundance and diversity of cetaceans in the Alboran Sea. Further, when both methodologies were applied in isolation, the structure and functioning of this cetacean community was poorly resolved. The combination of both approaches is therefore desirable when investigating niche partitioning among ecologically similar species within communities., This work was funded by Fundación Loro Parque, Fundación Biodiversidad, CEPSA (Compañía Española de Petroleos S.A.), EcoCet Project [CGL2011-25543], LIFE + Indemares [LIFE07NAT/E/000732], LIFE “Conservación de Cetáceos y Tortugas de Murcia y Andalucía” [LIFE02NAT/E/8610]. Thanks to the Consejería de Agricultura, Pesca y Medio Ambiente and the Agencia de Medio Ambiente y Agua (Junta de Andalucía) and to CREMA (Centro de Recuperación de Especies Marinas Amenazadas). J.G., F.R, and R.dS. were supported by the Spanish Ministry of Economy, Industry and Competitiveness through the Severo Ochoa Program for Centers of Excellence in R + D + I [SEV-2012-0262]. F.R was also supported by the “Juan de la Cierva-Incorporación Program” [IJCI-2015-24531].

Toxoplasma gondii , a serious animal and human protozoan pathogen of zoonotic potential,1 represents a real hazard to the already threatened health and conservation status of aquatic mammals and cetaceans worldwide,2 with T gondii -infected striped dolphins ( Stenella coeruleoalba ) also being prone to developing severe brain lesions causing their stranding and subsequent death.3 As with many other orofaecally transmitted pathogens, once shed into the surrounding environment – by infected felids …

This study investigates the female reproductive parameters and population demographics of bottlenose dolphins (Tursiops truncatus) in the Shannon Estuary, Ireland, using long-term relational sightings and photographic databases. Data were collected between 2008 and 2016, during 654 boat-based surveys, from two dolphin-watching vessels and a research vessel. During 1018 sightings, 4231 identifications of 184 individual dolphins were recorded. The population size was charted through direct counts of known dolphins from 2011 to 2015 (mean 142, range 131–150), with 145 extant individuals in 2015: 80 adults, 25 juveniles, and 40 calves. Excluding dependent calves, 121 individuals were sighted, of whom 98% (n = 119) were sighted in multiple years, with 64% (n = 77) sighted in all 4 years (2012–2015). Between 2008 and 2016, 37 reproductive females and 69 dependent calves were recorded. Overall, 35% (n = 13) of these females were sighted with one calf, 43% (n = 16) with two calves and 22% (n = 8) with three calves. An average of seven (range 3–10) calves were born each year. Parturition peaked in July. Weaning ages ranged from 2.0 to 4.1 (mean 2.9) years. The mean inter-birth interval ranged between 2.7 ± 0.6 and 3.5 ± 1.3 years, depending on the method used. Mean annual calving rate was 0.29 young-of-year/ reproductive female/year. Average crude birth rate was 0.07 ± 0.01. Fecundity was 0.26 ± 0.03. An average 11% of newborn calves were lost before age 1. These results are generally within the lower range of values reported for similar populations and provide essential data for conservation management and global bottlenose dolphin research. yes

Fo r the young of many species, social play is an important aspect of development. Previous research has shown that bottlenose dolphin calves engage in social play early in life. Despite these observations, little is known about the development of social play in this species . The present study examined the social play behavior of three aquarium-housed bottlenose dolphin calves during their first year of life. We were particu larly interested in the partner with who m each calf played as well as the initiator of social play bouts . Each calf was observed from birth until the end of its first year and all bouts of social and solitary play were recorded during observation sessions . While the calves engaged in both social and solitary play throughout their first year, play became increasingly social as they aged. The calves also became more likely to initiate social p lay interactions with increasing age . A calf's first social play partner was typically its mother, but other calves quickly rep laced the mother as the most common play partner. When it came to play partner preferences, we found that calves of similar age were preferred as play partners, but age similarity became less characteristic of play partners as the calves grew older. These findings likely reflect changes in the developmental co mpetence of each of the calves individually, and support the notion that calves use social play to challenge themselves.

Mercury exposure through the consumption of fish and shellfish represents a significant public health concern in the United States. Recent research has demonstrated higher seafood consumption and subsequent increased risk of methylmercury exposure among subpopulations living in coastal areas. The identification of high concentrations of total mercury in blood and skin among resident Atlantic bottlenose dolphins (Tursiops truncatus) in the Indian River Lagoon (IRL), a coastal estuary in Florida, alerted us to a potential public health hazard in the contiguous human population. Therefore, we analyzed hair mercury concentrations of residents living along the IRL and ascertained their sources and patterns of seafood consumption. The total mean mercury concentration for 135 residents was 1.53 ± 1.89 µg/g. The concentration of hair mercury among males (2.02 ± 2.38 µg/g) was significantly higher than that for females (0.96 ± 0.74 µg/g) (p < 0.01). Log transformed hair mercury concentration was significantly associated with the frequency of total seafood consumption (p < 0.01). Individuals who reported consuming seafood once a day or more were 3.71 (95% CI 0.84–16.38) times more likely to have a total hair mercury concentration over 1.0 µg/g, which corresponds approximately to the U.S. EPA reference dose, compared to those who consumed seafood once a week or less. Hair mercury concentration was also significantly higher among individuals who obtained all or most of their seafood from local recreational sources (p < 0.01). The elevated human mercury concentrations mirror the elevated concentrations observed in resident dolphins in the same geographical region. The current study is one of the first to apply the concept of a sentinel animal to a contiguous human population.

Acoustic communication is common in dolphins and encompasses a variety of sounds, either vocal or not. Among vocalizations, whistles are continuous narrow-band and frequency-modulated sounds, with a frequency range between 2-24 kHz. The aim of this study was to characterize the whistles of a resident group of bottlenose dolphins Tursiops truncatus in the coast of Aragua state (Venezuela) and to determine their association with surface behavior. On average, whistle frequency ranged from 7 to 16 kHz. Six types of whistles, according to the contour of frequency modulation, were found: constant, ascending, descending, ascending-descending, descending-ascending and multiple. Only two behavioral states were observed: traveling and socialization. There was significant association between the type of whistle and behavior: whistles of medium complexity (ascending-descending) were preferred during traveling and significantly avoided during socialization. Furthermore, whistles emitted during socialization were longer, of broader bandwidth, and spanning over lower frequencies than those emitted during traveling. The variation of whistles according to surface behavior confirms that they have a communicational value. Future research should focus on the causes and consequences of whistle emission to elucidate their referential function.

In order to investigate social structure, 11 years of individual photo-identification data of bottlenose dolphin were analysed. We examined the type of association indices between pairs of identified individuals; the patterns of affiliation between individual dolphins and the probabilities of association between individuals over time. Between 2001 and 2012, there were 272 encounters which resulted in the identification of 501 individuals. The discovery curve resulting from the photo-identification analysis indicated an open population with regular recruitment of new individuals. All individuals were found to be associated at an association index of

Tese de Doutoramento em Biologia do Comportamento apresentada ao ISPA - Instituto Universitário Ao longo dos anos, vários métodos de análise automática e semiautomática têm sido desenvolvidos para superar as limitações e a subjectividade da análise comportamental manual. A acelerometria, por exemplo, tem mostrado um enorme potencial em fornecer informações sobre o comportamento animal. Para este projecto, o comportamento de dois machos adultos de golfinhoroazes (Tursiops truncatus) foi estudado em cativeiro, através de diferentes metodologias: acelerometria, video-tracking e a análise acústica. Para os dados de acelerometria foi desenvolvido um algoritmo que classificou correctamente 86 comportamentos, agrupados em 8 categorias. O comportamento mais observado foi a Natação Dorsal e a análise de entropia revelou que o comportamento dos golfinhos possui uma estrutura altamente organizada e que poderá permitir a previsão da sequência de movimentos que sucedem a determinada acção. Adicionalmente, foi desenvolvido um sistema de video-tracking semi-automático, o D-Track. Este sistema quantifica, de forma não-invasiva, as trajectórias em 3D dos golfinhos na água com uma reconstrução tridimensional da piscina, usando câmaras de vídeo comuns. Os resultados mostraram que ambos os animais despenderam 85% do tempo à superfície na Área Profunda da piscina (5 metros de profundidade) e apresentaram velocidade média constante, com predominância das velocidades baixas (máximo de 1,7 ms-1). Este sistema é uma ferramenta inovadora que pode ser usada por laboratórios e parques temáticos para monitorizar as preferências e rotinas dos seus animais. As emissões acústicas dos golfinhos-roazes são divididas em sons pulsados (cliques de ecolocalização e burst-pulses) e não pulsados (assobios, podendo estes ser estereotipados ou variantes), sendo frequentemente associados com outros comportamentos. Numa primeira fase foram analisadas as taxas de emissão de assobios de seis golfinhos em cativeiro, em dois períodos distintos e em três contextos diferentes. Apenas uma categoria de assobios foi observada em ambos os períodos e considerada assobio assinatura, tendo sido associada ao mesmo animal em ambos os períodos. As taxas de emissão dos assobios foram 7,8 vezes mais elevadas em isolamento, comparando com o contexto social. Os assobios recolhidos entre 2012 e 2014 foram analisados através de dois softwares comerciais para extrair assobios (BELUGA) e categorizá-los automaticamente (ARTwarp). No entanto, os resultados mostraram que o ARTwarp não se aplica adequadamente a este tipo de dados, uma vez que muitos assobios são apenas abreviaturas de vocalizações mais longas, e mostrando que a classificação visual ainda é o melhor método de classificação destes sons. A combinação destas metodologias possui um enorme potencial para fornecer informações sobre movimentos, rotinas e vocalizações associadas aos sujeitos. O D-Track foi usado na tentativa de identificar o emissor mais provável das vocalizações, enquanto a acelerometria foi usada para explorar uma possível relação entre o comportamento e emissões acústicas específicas até agora sem sucesso. Em suma, o principal objectivo deste abordagem multi-disciplinar foi desenvolver métodos, num ambiente controlado, que possam ajudar a melhorar o bem-estar dos golfinhos em cativeiro e criar ferramentas que possam ser aplicadas em estudos no meio natural. Espera-se que os esforços deste projecto venha a contribuir para o avanço do conhecimento sobre estes animais. ABSTRACT: Over the years, automated and semi-automated methods have been developed to overcome the limitations and subjectivity of manual behavioral analyses. Accelerometry, for instance, has shown an enormous potential in providing information about animal behavior. In this project, two male common bottlenose dolphins (Tursiops truncatus) kept at a zoological facility, were used to study behavior, using accelerometry, video-tracking and acoustical techniques. An algorithm was developed that, using acceleration data, correctly classified 86 behaviors, grouped into 8 categories. The most common behavior observed was Dorsal Swim, and the entropy analysis indicated that the dolphins’ behavior contains a high order structure that may allow the prediction of which behavior will follow a specific action. A semi-automatic tracking system, D- Track, was also developed. It is able to quantify, non-invasively, the 3D trajectories of dolphins in the water, through a three-dimensional reconstruction of the pool using standard cameras. The data showed that both animals spent around 85% of the time at the surface of the Deep Area of the pool (5 meters deep) and showed a stable average speed, with slow speeds predominant (maximum 1.7 ms-1). This system is a novel tool that offers possibilities for laboratories and marine parks to monitor the preferences and routines of their animals. The underwater acoustical emissions of bottlenose dolphins are divided in pulsed (echolocation clicks and burst- pulses) and non-pulsed sounds (whistles, stereotyped or variant patterns), and it is known that various vocal emissions are frequently associated with other behavioral displays. For a primary analysis, the whistle emissions of six captive dolphins, in two separate time sets and three different contexts, were analyzed. Only one whistle contour category was found in both time sets and considered a signature whistle. This contour was associated with the same animal in both time sets. Whistle emission rates were 7.8 times higher in isolation as compared with social context. The data collected from 2012 to 2014 was also analyzed using two commercial software to extract (BELUGA) and automatically categorize (ARTwarp) the whistles; however, the results showed that ARTwarp does not work with this data set, since most of the whistles are just abbreviations of longer version emissions, and human-based visual classification proved to be a better classification method. The use of all these techniques combined has great potential in providing information on the movements, routines and associated individual vocalizations of the focal animals. The DTrack was used in an attempt to identify the “most-likely” emitter of the sounds while the accelerometer data was explored in an effort, so far unsuccessful, to find a relationship between behavioral patterns and specific vocal emissions. The overall purposes of this multi-approach research were to use the conditions of a controlled environment to develop methods that may help to improve the welfare of captive dolphins, and to create tools that are applicable to the investigations of these animals in the wild. It is hoped that some novel contributions and advances may come out of various developments and examples here presented.

This study investigated whether there is evidence of widespread niche partitioning based on environmental factors in the Black Sea and tested the hypothesis that physiographic factors may be employed as predictors. It addresses poorly researched areas with good habitat potential for the only three cetacean subspecies living in this area: the Black Sea short-beaked common dolphin (Delphinus delphis spp. ponticus), the Black Sea bottlenose dolphin (Tursiops truncatus spp. ponticus) and the Black Sea harbour porpoise (Phocoena phocoena spp. relicta). Generalized additive models (GAMs) were used to analyse data collected from multiple sources. In total, 745 sightings of the three species between 1998 and 2010 throughout the Black Sea were included. The analysis found depth and sea surface temperature to be the most important variables for separating the occurrence of the three species. Common dolphins occurred mainly in deep waters and in areas where the sea surface temperature was low, bottlenose dolphins were distributed primarily in shallower and warmer waters than common dolphins, and harbour porpoises were distributed in shallower waters with lower sea surface temperature than bottlenose dolphins. This study suggests strong niche segregation among the three cetacean species. The study is also the first contribution to the basic information of cetacean species distribution and habitat preferences in the Black Sea as a whole. Knowledge of the distribution of the three dolphin species in the study area is essential to establish conservation measures for these populations.