Dolphin whistles can be useful tools in identifying units of conservation

Data collection and processing in the Azores was funded by Fundação para a Ciência e a Tecnologia (FCT) and Fundo Regional da Ciência e Tecnologia (FRCT), through research projects TRACE-PTDC/MAR/74071/2006 and MAPCET-M2.1.2/F/012/2011 (FEDER, the Competitiveness Factors Operational (COMPETE), QREN European Social Fund, and Pro convergencia Açores/EU Program). We also thank FCT for supporting MARE (UID/MAR/04292/2019) and OKEANOS (UIB/05634/2020), as well as for the research grants awarded to PR (SFRH/BPD/108007/2015) and CI (Project Awareness - PTDC/BIA-BMA/30514/2017). SMA is supported through project SUMMER (H2020-EU.3.2.3.1, GA 817806). Data collection by SECAC was funded by the EU LIFE programme—project LIFE INDEMARES (LIFE 07/NAT/E/000732)— and the Fundación Biodiversidad under the Spanish Ministry of Environment, Rural and Marine Affairs (project ZEC-TURSIOPS). EP was supported by a LLP/Erasmus grant 2010–2011 for collecting data in the Canary Islands.Background: Prioritizing groupings of organisms or ‘units’ below the species level is a critical issue for conservation purposes. Several techniques encompassing different time-frames, from genetics to ecological markers, have been considered to evaluate existing biological diversity at a sufficient temporal resolution to define conservation units. Given that acoustic signals are expressions of phenotypic diversity, their analysis may provide crucial information on current differentiation patterns within species. Here, we tested whether differences previously delineated within dolphin species based on i) geographic isolation, ii) genetics regardless isolation, and iii) habitat, regardless isolation and genetics, can be detected through acoustic monitoring. Recordings collected from 104 acoustic encounters of Stenella coeruleoalba, Delphinus delphis and Tursiops truncatus in the Azores, Canary Islands, the Alboran Sea and the Western Mediterranean basin between 1996 and 2012 were analyzed. The acoustic structure of communication signals was evaluated by analyzing parameters of whistles in relation to the known genetic and habitat-driven population structure. Results: Recordings from the Atlantic and Mediterranean were accurately assigned to their respective basins of origin through Discriminant Function Analysis, with a minimum 83.8% and a maximum 93.8% classification rate. A parallel pattern between divergence in acoustic features and in the genetic and ecological traits within the basins was highlighted through Random Forest analysis. Although it is not yet possible to establish a causal link between each driver and acoustic differences between basins, we showed that signal variation reflects fine-scale diversity and may be used as a proxy for recognizing discrete units. Conclusion: We recommend that acoustic analysis be included in assessments of delphinid population structure, together with genetics and ecological tracer analysis. This cost-efficient non-invasive method can be applied to uncover distinctiveness and local adaptation in other wide-ranging marine species.Publisher PDFPeer reviewe

Isolation and Genomic Analysis of the Cetacean Y-chromosome

The male-specific mammalian Y-chromosome represents a powerful tool for studying malemediated gene flow and genome evolution. Here it was possible to identify 7 polymorphic microsatellites for the first time in an odontocete species, using a combination of cell culture, cytogenetics and molecular approaches. Initially, the development of an efficient and repeatable methodology for obtaining a growing lymphocyte culture that facilitated the isolation of individual chromosomes is described. Flow karyotypic characterization and isolation of individual chromosomes via flow sorting or microdissection is reported for the killer whale (Orcinus orca). Microdissected Y-chromosomes from the killer whale and bottlenose dolphin (Tursiops truncatus) were screened for sequences containing microsatellite motifs. 15 and 10 male-specific microsatellites were identified from the killer whale and bottlenose dolphin, respectively. Additional microsatellite loci were identified from previously published fin whale Y-chromosome sequence. 6 markers designed from heterologous sequences amplified from sperm whales (Physeter macrocephalus), were also screened for variation. All 31 markers were monomorphic in the bottlenose dolphin, only 2 loci showed 2 variants in the killer whale and 7 were polymorphic in the sperm whale. In addition 162 anonymous regions of the Y-chromosome, isolated from the delphinid species were used to characterize the comparative composition of the ‘Y’ relative to the autosomes in these species. Characteristics are discussed in the context of the genome as a whole, species-specific history and with reference to the expected patterns of mammalian Y-chromosome evolution

Social and population structure of striped and Risso's dolphins in the Mediterranean Sea

The aim of this research was to apply genetic methods to a better understanding of the evolution of population genetic structure in two dolphin species inhabiting a shared geographic range in the Mediterranean Sea and eastern North Atlantic (ENA). In support of this I analysed the pattern of population subdivision, genetic variability and group kin structure of striped (Stenella coeruleoalba) and Risso's dolphins (Grampus griseus) in the Mediterranean Sea, and compare theassessed the level of genetic differentiation between Mediterranean and ENA populations. The specific objectives were to: 1- study their distribution in the core study area (the Ligurian Sea) and group size variation as a possible behavioural responses to environmental features; 2- assess patterns of kinship and association within and between social groups (based on estimates of R); and 3- investigate patterns of genetic subdivision among the putative striped and Risso's dolphin populations within the Mediterranean Sea, and in comparison with the ENA. Risso's dolphins showed a clear preference for the steeper continental slope, while striped dolphins did not show this distribution preference. Samples from 165 striped dolphins were collected from the Mediterranean Sea (Adriatic, Tyrrhenian, and Spam) and ENA, and were analysed at 8 microsatellite DNA loci. The comparison between the Mediterranean and the ENA populations showed a clear separation (Fst=0.055). All loci were polymorphic (4-22 alleles), and mean Ho ranged from 0.68 in the Tyrrhenian to 0.8 in the ENA. All comparisons between putative populations showed significant differentiation, including the populations of the eastern (Adriatic) and western (Tyrrhenian) seas of Italy. Analysis of the Risso's dolphin samples (n=50) collected in the Mediterranean and the ENA showed that the two populations were significantly differentiated (Fst=0.0296). All loci were polymorphic (up to 17 alleles), and mean Ho was 0.467 m the Mediterranean, 0.548 in the ENA. Analysis of 619 bp of sequence of the mtDNA control region revealed 28 variable sites defining 16 unique haplotypes among the two populations. The degree of differentiation was highly significant for both FST (0.260) and ɸST (0.542).Individual relatedness within and between social groups of striped dolphins was investigated m the Ligurian population. On average the values were higher for intra- than inter-group comparisons, and females showed significantly higher relatedness within than between groups. The kin structure of the Risso's dolphins in the Ligurian population showed that females had a considerably higher relatedness within groups than among groups. For both species, the data suggest a relatively fluid model of kin structure with a trend for female philopatry, and male dispersal. My results indicate fine-scale population structure in both species, and significant differentiation between the Mediterranean and North Atlantic populations. A hierarchical pattern of kin structure is clearly influenced by social group structure and the dispersal behaviour of males and females, though there are some differences between the species, probably related to differences in social structure and habitat use

Molecular ecology of Bottlenose (Tursiops sp.) and common (Delphinus sp.) Dolphins

Bottlenose (Tursiops sp.) and common dolphins (Delphinus sp.) are amongst the most common small cetaceans. They both have a world-wide distribution from warm temperate to tropical waters inhabiting pelagic and coastal waters, and they both show high morphological variability throughout their range, leaving the taxonomic issues in both species unresolved. This thesis provides a comparative assessment of these two species, by molecular analysis, especially in the context of comparing coastal and pelagic populations of each species. The aim is to better understand the evolutionary processes and the factors involved in shaping the population structure in small delphinids. The strategy 1 followed was: 1) Analyse the population structure of the bottlenose and common dolphins on a worldwide scale and compare large scale patterns in the context of known similarities and differences with respect to life history. 2) Analyse populations on a smaller geographic scale (Mediterranean Sea and South Africa) to further understand the relationship between habitat and population generic structure. On a worldwide scale, bottlenose dolphins showed high genetic diversity and strong population structure, both between different and similar morphotypes, suggesting limited gene flow. Two populations, of the same morphotype, have diverged considerably to the extent that they should be considered different species. Common dolphins showed lower genetic diversity and weak population structure even over a large geographic range, suggesting higher level of gene flow. However, this species also has similar morphotypes that were genetically differentiated from one another. On a smaller geographic scale, we found a similar pattern of population structure, with the bottlenose dolphin showing higher population divergence than common dolphins. However, both species provided evidence supporting the role of habitat in defining population structure in these species. These findings should facilitate the development of effective conservation and management strategies for these species, especially for the specific case studies for populations in the Mediterranean Sea and off the Natal coast of South Africa

Population genetics of species on the genera Tursiops and Delphinus within the Gulf of California and along the western coast of Baja California.

This present study investigated the evolution of population genetic structure of two closely related cetacean species, bottlenose (Tursiops truncatus) and common dolphins (Delphinus spp.) within the Gulf of California (GC) and along the West Coast of Baja California. In this study, we found evidence of strong genetic differentiation in both bottlenose and common dolphin populations in the absence of physical barriers. The comparison of the patterns of population genetic differentiation found here for bottlenose and common dolphins supports the hypothesis of local habitat dependence and resource specialization at both the population and putative species level. Fine-geographic scale structure was detected in coastal bottlenose dolphins, which seemed to be strongly associated to the biogeographic subdivision of the Gulf of California and western coast of Baja California. This result suggests that gene flow among bottlenose dolphin coastal populations might be restricted by local dependence on diverse ecological conditions. In contrast, the long-beaked common dolphin genetic structure did not reflect the habitat heterogeneity of the region to the same extent. The difference in foraging specialization between coastal and offshore populations of both bottlenose and common dolphins is reflected in the pattern of genetic structure observed at a broader geographic scale. Overall, the results support the hypothesis that local habitat dependence promotes population differentiation in the absence of physical boundaries to dispersal in these highly mobile species. This study provides an unusual insight into the conditions that lead to incipient speciation in these groups. Divergence among common dolphin populations appears to be associated with changes in the paleoceanographic conditions of the region to the extent that reciprocal monophyly between the sympatric D. delphis and D. capensis forms has evolved within the Holocene timeframe

Dusky dolphins in New Zealand: group structure by sex and relatedness

The sex of and genetic relatedness among interacting individuals are known to be biologically fundamental features that characterize the composition of animal groups. Current work continues to illuminate reasons for the variety of animal social patterns, including patterns in group membership. I investigated the composition of dusky dolphin groups relative to sex and relatedness at two locations in New Zealand. In Kaikoura, dusky dolphins are found year-round, foraging nocturnally on verticallymigrating prey and socializing in distinct group types (mating, nursery, and adult) during the day. By contrast, dusky dolphins use Admiralty Bay, where they feed diurnally on small schooling fishes, primarily in the winter. Molecular sexing revealed the sex of 107 dusky dolphins. The Kaikoura data support previous findings that small mating groups consist mostly of males and indicate that small adult groups can consist of either or both sexes. In Admiralty Bay, the percentage of female dolphins present during the study was estimated to be only 7.4%âÂÂ22.2% (95% confidence interval, n=88). A randomization test further indicates that dusky dolphins in Admiralty Bay grouped preferentially with same-sex individuals. Nuclear and mitochondrial markers were used to investigate patterns of relatedness. Dusky dolphins sampled in Kaikoura (n=17) and Admiralty Bay (n=47) were genotyped at seven microsatellite loci, and genetic relatedness among all genotyped pairs was estimated. A randomization test indicates that dusky dolphins did not group preferentially by relatedness in Admiralty Bay. Grouping history for 13 genotyped samples was also known from a multi-year photographic record of individually distinctive dusky dolphins. No relationship was found between these longer-term grouping patterns and genetic relatedness. The d-loop region of the mitochondrial DNA (mtDNA) was sequenced for 197 dusky dolphins. The pattern of grouping among dolphins with different haplotypes indicates that dusky dolphin groups are not strongly structured by maternal lineages. However, data from eight individual dusky dolphins hint that nursery groups in Kaikoura tend to consist of dolphins that share a maternal ancestor. This investigation raises many questions about the nature of dusky dolphin social organization and suggests promising avenues for finer-grained investigations into the causes and consequences of dusky dolphin group structure

Macro- and micro-geographic variation of short-beaked common dolphin’s whistles in the Mediterranean Sea and Atlantic Ocean

Author Posting. © The Author(s), 20113. This is the author's version of the work. It is posted here by permission of Taylor & Francis for personal use, not for redistribution. The definitive version was published in Ethology Ecology & Evolution 26 (2014): 392-404, doi:10.1080/03949370.2013.851122.Genetic studies have shown that there are small but significant differences between the short-beaked common dolphin populations in the Atlantic Ocean and those in the Mediterranean Sea. The short-beaked common dolphin is a highly vocal species with a wide sound production repertoire including whistles. Whistles are continuous, narrowband, frequency-modulated signals that can show geographic variation in dolphin species. This study tests whether the differences, highlighted by genetic studies, are recognisable in the acoustic features of short-beaked common dolphin’s whistles in the two adjacent areas of the Atlantic Ocean and the Mediterranean Sea. From a selected sample of good quality whistles (514 recorded in the Atlantic and 193 in the Mediterranean) 10 parameters of duration, frequency and frequency modulation were measured. Comparing data among basins, differences were found for duration and all frequency parameters except for minimum frequency. Modulation parameters showed the highest coefficient of variation. Through discriminant analysis we correctly assigned 75.7% of sounds to their basins. Furthermore, micro-geographic analysis revealed similarity between the sounds recorded around the Azores and the Canary archipelagos and between the Bay of Biscay and the Mediterranean Sea. Results are in agreement with the hypothesis proposed by previous genetic studies that two distinct populations are present, still supposing a gene flow between the basins. This study is the first to compare shortbeaked common dolphin’s whistles of the Atlantic Ocean and the Mediterranean areas.Data collection and processing in the Azores was conducted under projects POCTI/BSE/38991/01, PTDC/MAR/74071/2006 and M2.1.2/F/012/2011, supported by FCT (Fundação para a Ciência e a Tecnologia) and DRCTC/SRCTE (Secretaria Regional de Ciência, Tecnologia e Equipamentos), FEDER funds, the Competitiveness Factors Operational (COMPETE), QREN European Social Fund and Proconvergencia Açores Program. We acknowledge funds provided by FCT to LARSyS Associated Laboratory & IMAR-University of the Azores/ the Thematic Area E of the Strategic Project (OE & Compete) and by the DRCTC – Government of the Azores pluriannual funding. M.A. Silva was supported by an FCT postdoctoral grant (SFRH/ BPD/29841/2006). I. Cascão and R. Prieto were supported by FCT doctoral grants (SFRH/BD/ 41192/2007 and SFRH/BD/32520/2006, respectively) and R. Prieto by a research grant from the Azores Regional Fund for Science and Technology (M3.1.5/F/115/2012). Data collection by SECAC (Society for the Study of Cetaceans in the Canary Archipelago) was funded by the U.E. LIFE programme – project LIFE INDEMARES (LIFE 07/NAT/E/000732)- and the Fundación Biodiversidad, under the Spanish Ministry of Environment, Rural and Marine Affairs (project ZEC-TURSIOPS).2014-11-0

Variation in Social Behavior Throughout the Estrous Cycle of a Captive Killer Whale \u3ci\u3eOrcinus orca\u3c/i\u3e

The study of cetaceans in captivity provides information on behavior, acoustics, reproduction and physiology that is often difficult to obtain with free-ranging populations. The present study examined the influence of the estrous cycle of a captive female killer whale on the rate, duration, initiation and reception of social behavior she performed with her only pool mate, a male Atlantic bottlenose dolphin. Although these two delphinid species do not commonly associate in the wild, these pool mates often engaged in affiliative tactile and social behaviors. The objectives of this project were to: (a) examine the influence of cycli~ gonadal steroid hormones on social behavior in the killer whale, and (b) document a rare interspecific interaction. A total of five estrous cycles, covering the span of eight months, were analyzed in the present study. Weekly blood serum samples from the female killer whale were analyzed to ascertain the estrous cycle phase of this focal subject. Hormonal data was then compared to opportunistic video footage of the subjects\u27 interaction. Based on previous reproductive endocrinology studies, it was hypothesized that the female killer whale\u27s initiation of such behaviors would increase during the fertile window of behavioral estrus. The average rate of female-initiated tactile behavior, female-to-male chasing, and pair swimming was significantly higher during the luteal phase than the follicular phase, with a peak in such behaviors occurring more than a week after the fertile window. In addition, the average duration of female initiated tactile behavior was significantly longer during the luteal phases. Male-initiated social behaviors did not significantly change in rate or duration throughout the focal subject\u27s estrous cycle, suggesting that the male bottlenose was not perceptive to the killer whale\u27s hormonal cycling. Furthermore, the average duration of resting by the female subject did not significantly change throughout the estrous cycle, suggesting that the increase in socially proceptive behaviors is most likely not a byproduct of an overall increase in general activity level due to a hormonal surge following ovulation

Behavior and fission-fusion dynamics of common dolphin (Delphinus delphis) groups with calves in the South of Portugal

Fission-fusion dynamics describe animal social systems that are fluid and characterized by varying group sizes. Costs and benefits associated with grouping are considered to be the driving force for separation (fission) and joining (fusion) of individuals, resulting from ecological (e.g., food availability, predator abundance) and social (e.g., behavioral state, presence of calves) factors. The behavioral state gives insights into an animal’s ecology and allows protection of the species or population. The present study investigates which factors influence behavioral state and fission-fusion dynamics in common dolphin (Delphinus delphis) groups with calves in the south of Portugal. Between June and October of 2016, 2017 and 2019, 39 focal follows based on unmanned aerial vehicles (UAVs) were conducted, resulting in 768, 30-second behavioral samples (384 minutes). A multinomial model based on generalized estimating equations framework was used to model: i) the behavioral state by testing the responses to group size, total number of calves and month; ii) and fission-fusion dynamics assessing the effect of behavioral state, month, total number of calves and time of the day. The behavioral state of dolphin groups with calves was statistically significantly affected by the total number of calves and month. As the number of calves increased, resting behavior was less likely to occur than travelling (OR = 0.7, p = 0.015). Dolphin groups with calves were less likely to be socializing in July than to travel in June (OR = 0.1, p = 0.021). Group size had no statistically significant influence on the behavioral state in the present study. This study also revealed, that common dolphins in the south of Portugal exhibit a high rate of fission-fusion dynamics, but were not influenced by the factors considered in this study (i.e., behavioral state, month, total number of calves and time of the day). By assessing behavior and fine-scale social dynamics in common dolphins, this study enhances the current understanding of ecological and social aspects shaping grouping patterns and behavior in common dolphin groups with calves. This study also highlights the advantages of using unmanned aerial vehicles (UAVs) to assess behavioral data in wild animals.A organização de indivíduos em grupos é comum nos mamíferos e a maioria das espécies apresentam comportamento social durante o período de reprodução e cuidados parentais. Os laços sociais entre indivíduos que partilham o mesmo ambiente podem ter impactos sobre os próprios e sobre a sobrevivência da descendência. O termo fissão-fusão (FF) foi inicialmente utilizado para descrever o sistema social dos primatas que alteram o tamanho do grupo frequentemente e dividem-se em subunidades. A dinâmica da fissão-fusão descreve, portanto, sistemas sociais são fluidos e caracterizados por tamanhos de grupo variáveis. Os custos e benefícios associados ao agrupamento são considerados a principal razão para a separação (fissão) e união (fusão) de grupos, provavelmente provenientes de factores sociais (e.g., estado comportamental, presença de crias) e ecológicos (e.g., disponibilidade de alimento, presença de predadores). Por exemplo, diferenças na distribuição espacial e temporal de recursos alimentares podem favorecer padrões de associação flexíveis, para reduzir a competição intra-específica e aumentar a possibilidade de explorar novos recursos. Em troca, associações mais coesas e estáveis podem ser formadas com o objetivo de maximizar a defesa contra predadores. Assim, o risco de predação pode favorecer a agregação de indivíduos em locais de descanso comunitários durante a noite, que posteriormente se dividem em pequenos grupos durante o dia para alimentação. Adicionalmente, a dinâmica de fissão-fusão pode ser influenciada pelo sexo, idade e/ou fase reprodutiva dos indivíduos. Em algumas espécies, os machos podem apresentar taxas de fusão mais elevadas a fim de cooperarem com indivíduos relacionados e impedir o acesso às fêmeas por machos de grupos vizinhos. As dinâmicas de fissão-fusão são comuns em algumas espécies de primatas, elefantes, hienas malhadas e golfinhos. O estudo da socialidade e comportamento em mamíferos pode fornecer informações importantes sobre a sua evolução e fornecer informação relevante para a proteção das espécies, especialmente as ameaçadas de extinção. Os cetáceos são mamíferos marinhos de maturação lenta e uma expectativa de vida longa. Este grupo de organismos vive a maior parte da sua vida debaixo de água, o que torna particularmente difícil o estudo dos seus sistemas sociais e comportamentos. Entre os cetáceos, existem grandes variações inter- e intra-específicas na organização social, desde ligações sociais estáveis e duradouras (e.g., orcas, cachalotes, cachalotes, baleias-piloto de barbatanas longas) a sociedades fluidas com uma elevada dinâmica de fissão-fusão (e.g., golfinho riscado, golfinhos-roaz, golfinhos de risso). Estudos recentes identificaram como factores ambientais e sociais que afetam a dinâmica de fissão-fusão o comportamento, sexo, grau de parentesco, sazonalidade e pressões antropogénicas. Veículos aéreos não tripulados (UAV), vulgarmente conhecidos como "drones", são uma tecnologia inovadora e que tem vindo a sofrer um rápido desenvolvimento nos últimos anos. Geralmente, os UAV podem ser distinguidos em dois tipos: 1) UAV de asa fixa (FW) e 2) UAV de descolagem e aterragem verticais (VTOL). A funcionalidade dos sistemas VTOL é comparável à dinâmica dos helicópteros. A maioria dos modelos usa 4 a 8 rotores que permitem que a aeronave paire em uma posição estacionária, permaneça em baixas altitudes, mova-se lentamente e permita decolagens e aterragens verticais, eliminando a necessidade de uma pista. Além disso, os modelos comerciais incluem câmeras de alta definição integradas com estabilizadores de imagem mecânicos (ou seja, Gimbal), permitindo que o piloto capture vídeos e/ou fotos em alta qualidade de uma perspectiva vantajosa. Além disso, os VTOLs são geralmente leves (< 5 kg), portáteis, económicos e prontamente disponíveis em vários fabricantes comerciais. No entanto, tais sistemas requerem controle ativo por um piloto remoto e sua distância máxima de voo é limitada a uma faixa de dezenas de quilómetros, enquanto a vida útil da bateria de cerca de 30 a 45 minutos permite apenas tempos de transmissão bastante curtos em áreas de pesquisa menores em comparação com FWs. As características avançadas dos modernos UAV VTOL torna-os versáteis para várias aplicações, incluindo a investigação de vida selvagem, incluindo estudos de comportamento e populacionais, recolha de amostras biológicas, monitorização e estudo de habitat. O sucesso dos UAV neste campo pode ser explicado pela diversidade dos modelos existente e pelas suas inúmeras formas de funcionamento, ao mesmo tempo que continuam a ser sistemas rentáveis e eficazes na colheita de dados sistemáticos e de alta resolução (temporal e espacial). Apesar das numerosas vantagens do uso de veículos aéreos não tripulados para a investigação da vida selvagem, a tecnologia tem limitações e pouco se sabe sobre os impactos que os UAV podem causar nos animais selvagens. As diferentes populações de uma espécie podem apresentar respostas idiossincráticas à presença de um UAV, dependendo de fatores tais como a espécies, fase de vida, habitat, condições ambientais tipo de UAV bem como, o método de operação (por exemplo, ruído emitido, velocidade, distância). Considerando as espécies de pequenos cetáceos (p. ex., delfinídeos), as respostas comportamentais como reacção a um UAV que se aproxima, permanecem pouco investigadas. Contudo, as provas actuais indicam que os UAV voando a baixas altitudes nas proximidades de diferentes espécies de golfinhos desencadeiam respostas comportamentais a curto prazo dos animais. O presente estudo investiga quais os fatores que influenciam o estado comportamental e a dinâmica de fissão-fusão em golfinhos comuns (Delphinus delphis) em grupos com cria no Sul de Portugal. Entre Junho e Outubro de 2016, 2017 e 2019, foram realizadas 39 amostras focais usando UAV, resultando num total de 768 amostras comportamentais tendo por base intervalões de 30 segundos (384 minutos). Utilizando equações de estimativa generalizada, modelou-se: i) o estado comportamental, testando as respostas ao tamanho do grupo, número total de crias; ii) e a dinâmica de fissão-fusão em função do estado comportamental, mês, número total de crias e hora do dia. As variáveis mês e número de cria mostraram ter um efeito significativo no estado de comportamento dos grupos de golfinhos com cria. Com o aumento do número de crias, o comportamento de repouso foi significativamente menos provável de ser observado do que o de viajar. Por outro lado, a probabilidade de avistar grupos com cria a descansar no mês julho foi significativamente inferior à probabilidade de observar grupos a viajar em Junho. Este estudo revelou que os golfinhos comuns com crias no Sul de Portugal, apresentam uma elevada taxa de dinâmica de fissão-fusão, mas não foram observados efeitos significativos do estado comportamental, número total de crias e hora do dia na dinâmica de fissão-fusão, exceto para a variável mês. A avaliação do comportamento e a dinâmica social de grupos de golfinhos comum com cria permitiu uma melhor compreensão dos aspetos ecológicos que influenciam os padrões de agrupamento e comportamento deste animais. Adicionalmente, este estudo demonstra que a utilização de veículos aéreos não tripulados (UAV) pode ser uma mais valia para o estudo comportamental de animais selvagens pela sua eficácia e qualidade dos dados recolhidos

¿Hogar dulce hogar? Amplios rangos de desplazamiento de delfínidos residentes y socialmente estables (Globicephala macrorhynchus)

Los patrones de movimiento de las poblaciones de delfínidos son generalmente limitados en el espacio, con la excepción de la orca (Orcinus orca). Además, la información sobre las grandes migraciones de estos animales es limitada en relación con la estructura social, estatus de residencia o el propósito de la migración. En el presente trabajo, la comparación de catálogos de fotoidentificación de calderón tropical (Globicephala macrorhynchus) de Madeira y Azores mostró que cinco animales adultos han realizado un viaje de ida y vuelta, de no menos de 2000 km. Estos delfínidos pertenecen a un grupo residente en Madeira, tienen una fidelidad de larga duración y fueron fotografiados en Azores durante una parada aparente, de al menos 10 días, seguramente para la cría y alimentación. El análisis de los patrones de asociación de estos individuos muestra que fueron registrados juntos en múltiples ocasiones durante todo el periodo de estudio, sugiriendo que son miembros de una unidad cohesionada. Estos descubrimientos amplían nuestro entendimiento sobre el rango de distribución y movimiento de estos animales y sugieren cautela al establecer los estatus de residencia de los delfínidos.Movement patterns of delphinid populations are generally known to occur within specific geographical areas; with the exception of the killer whale (Orcinus orca). Additionally, knowledge of wide-ranging migrations in these animals are mainly attributed to individual records with limited information on their social structure, residency status or purpose of migration. Here, a comparison of photographic-identification catalogues of short-finned pilot whales (Globicephala macrorhynchus) from the two most isolated archipelagos of the North Atlantic (Madeira and Azores) shows that five well-marked adult animals have made a round-trip movement, of no less than 2000 km. These delphinids belong to the main resident pod in Madeira, where they present long-term site fidelity and were photographed in the Azores during an apparent stop (of at least 10 days), most likely for breeding or feeding purposes. The analysis of the association patterns of these individuals shows that they were sighted together on multiple occasions during the entire study period, suggesting that they are members of a cohesive unit. These findings broaden our understanding on these animals’ home ranges and suggest caution when establishing residency status in delphinids