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Photo-identification is one of the best practices to estimate the abundance of cetaceans and, as such, it can help to obtain the biological information necessary to decision-making and actions to preserve the marine environment and its biodiversity. The Risso's dolphin is one of the least-known cetacean species on a global scale, and the distinctive scars on its dorsal fin proved to be extremely useful to photo-identify single individuals. The main novelty of this paper is the development of a new method based on deep learning, called Neural Network Pool (NNPool), and specifically devoted to the photo-identification of Risso's dolphins. This new method also includes the unique function of recognizing unknown vs known dolphins in large datasets with no interaction by the user. Moreover, the new version of DolFin catalogue, collecting Risso's dolphins data and photos acquired between 2013-2018 in the Northern Ionian Sea (Central-eastern Mediterranean Sea), is presented and used here to carry out the experiments. Results have been validated using a further data set, containing new images of Risso's dolphins from the Northern Ionian Sea and the Azores, acquired in 2019. The performance of the NNPool appears satisfying and increases proportionally to the number of images available, thus highlighting the importance of building large-scale data set for the application at hand.

espanolLos patrones de movimiento de las poblaciones de delfinidos son generalmente limitados en el espacio, con la excepcion de la orca (Orcinus orca). Ademas, la informacion sobre las grandes migraciones de estos animales es limitada en relacion con la estructura social, estatus de residencia o el proposito de la migracion. En el presente trabajo, la comparacion de catalogos de fotoidentificacion de calderon tropical (Globicephala macrorhynchus) de Madeira y Azores mostro que cinco animales adultos han realizado un viaje de ida y vuelta, de no menos de 2000 km. Estos delfinidos pertenecen a un grupo residente en Madeira, tienen una fidelidad de larga duracion y fueron fotografiados en Azores durante una parada aparente, de al menos 10 dias, seguramente para la cria y alimentacion. El analisis de los patrones de asociacion de estos individuos muestra que fueron registrados juntos en multiples ocasiones durante todo el periodo de estudio, sugiriendo que son miembros de una unidad cohesionada. Estos descubrimientos amplian nuestro entendimiento sobre el rango de distribucion y movimiento de estos animales y sugieren cautela al establecer los estatus de residencia de los delfinidos EnglishMovement 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

Wide-ranging connectivity patterns of common bottlenose dolphins (Tursiops truncatus) are generally poorly known worldwide and more so within the oceanic archipelagos of Macaronesia in the North East (NE) Atlantic. This study aimed to identify long-range movements between the archipelagos of Macaronesia that lie between 500 and 1,500 km apart, and between Madeira archipelago and the Portuguese continental shelf, through the compilation and comparison of bottlenose dolphin's photo-identification catalogues from different regions: one from Madeira (n = 363 individuals), two from different areas in the Azores (n = 495 and 176), and four from different islands of the Canary Islands (n = 182, 110, 142 and 281), summing up 1791 photographs. An additional comparison was made between the Madeira catalogue and one catalogue from Sagres, on the southwest tip of the Iberian Peninsula (n = 359). Results showed 26 individual matches, mostly between Madeira and the Canary Islands (n = 23), and between Azores and Madeira (n = 3). No matches were found between the Canary Islands and the Azores, nor between Madeira and Sagres. There were no individuals identified in all three archipelagos. The minimum time recorded between sightings in two different archipelagos (≈ 460 km apart) was 62 days. Association patterns revealed that the individuals moving between archipelagos were connected to resident, migrant and transient individuals in Madeira. The higher number of individuals that were re-sighted between Madeira and the Canary Islands can be explained by the relative proximity of these two archipelagos. This study shows the first inter-archipelago movements of bottlenose dolphins in the Macaronesia region, emphasizing the high mobility of this species and supporting the high gene flow described for oceanic dolphins inhabiting the North Atlantic. The dynamics of these long-range movements strongly denotes the need to review marine protected areas established for this species in each archipelago, calling for joint resolutions from three autonomous regions belonging to two EU countries. Partnership Program (US) and project ‘‘Cetáceos, Oceanografía y Biodiversidad de las Aguas Profundas de La Palma y El Hierro’’ funded by ‘‘Ministerio de Ciencia e Innovación’’ of the Spanish Government, grant number CETOBAPH-CGL2009-1311218 supported the work in the Canary Island. In Madeira, this study was supported by the Oceanic Observatory of Madeira through the project M1420-01-0142-FEDER-000001 and by the Portuguese Foundation for Science and Technology through the strategic project UID/MAR/04292/2020. Ana Dinis and Filipe Alves have grants funded by ARDITI— Madeira’s Regional Agency for the Development of Research, Technology and Innovation, throughout the project M1420-09- 5369- FSE- 000002, and Annalisa Sambolino is supported by the Portuguese Foundation for Science and Technology through the PhD grant number SFRH/BD/1416092018. In Azores, the MONICET platform is supported by project MEEMO (ACORES-01-0145-FEDER-000079) and Marta Tobena is supported by a PhD grant (M31a/F/0722015). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. info:eu-repo/semantics/publishedVersion

Photo-identification is a widely used non-invasive technique in biological studies for understanding if a specimen has been seen multiple times only relying on specific unique visual characteristics. This information is essential to infer knowledge about the spatial distribution, site fidelity, abundance or habitat use of a species. Today there is a large demand for algorithms that can help domain experts in the analysis of large image datasets. For this reason, it is straightforward that the problem of identify and crop the relevant portion of an image is not negligible in any photo-identification pipeline. This paper approaches the problem of automatically cropping cetaceans images with a hybrid technique based on domain analysis and deep learning. Domain knowledge is applied for proposing relevant regions with the aim of highlighting the dorsal fins, then a binary classification of fin vs. no-fin is performed by a convolutional neural network. Results obtained on real images demonstrate the feasibility of the proposed approach in the automated process of large datasets of Risso&rsquo, s dolphins photos, enabling its use on more complex large scale studies. Moreover, the results of this study suggest to extend this methodology to biological investigations of different species.

AIM: The knowledge of a species biogeographical patterns greatly enhances our understanding of geographical ecology, which can improve identifying key conservation needs. Yet, this knowledge is still scarce for many marine top predators. Here, we aim to analyse movement patterns and spatial structuring of a large predator, the short‐finned pilot whale Globicephala macrorhynchus, over a wide geographical area. LOCATION: North‐east Atlantic, in Macaronesian archipelagos (Azores, Madeira and Canaries) and Iberian Peninsula (Sagres). METHODS: We used likelihood techniques to estimate residency times and transition probabilities and carried out social analysis from individual photographic identification data, and analysed year‐round distribution from effort‐related sightings, collated between 1999 and 2015. RESULTS: The best‐fitting models included emigration and reimmigration and showed different residency times within each archipelago. A total of 26 individual movements from 21 individuals (from a sample of >2,300 individuals) were recorded between Madeira and the neighbouring archipelagos, and heterogeneous transition probabilities were estimated within and between areas. A social network diagram showed associations from animals with distinct residency patterns. Higher significant sighting rates were recorded during autumn in the Azores and Madeira. MAIN CONCLUSIONS: The variation in site fidelity and year‐round occupancy among areas of the Macaronesia is consistent with some degree of population structuring, which combined with a connectivity network and seasonal inflows from animals inhabiting offshore waters, support the development of a complex social and geographical ecology in short‐finned pilot whales. The combination of techniques applied in this study was an effective way to estimate parameters of movement, which could be a good practice to be used for other scenarios and species.

Knowledge of the residency patterns of marine mammals is an important element for management and conservation strategies. Here we investigate a population of Grampus griseus off Pico Island, Azores. Our data set covers the period 2004–2007, based on at-sea observations of 1,250 individually identified animals, 303 of known or assumed sex. Using photo identification and GPS locations we calculated mean monthly sighting rates and lagged identification rates to analyze temporal patterns, and estimated kernel density to study the home range. Our results show site fidelity and relatively restricted home ranges, which corroborate the existence of a resident population on the study site. We further document sex differences, including a higher number of males present in the area at any given time but females staying for longer consecutive periods, and male home ranges with significantly less overlap than those of females. These observations are consistent with a mating system based on multimale pods defending areas where females periodically return. We hypothesize that squid distribution is a major factor in structuring these patterns. These findings reinforce the need for a precautionary management approach that would include limiting pressure from commercial activities. info:eu-repo/semantics/publishedVersion

Summary The Risso’s dolphin (Grampus griseus) is the fifth largest member of the family Delphinidae. Variation in coloration is one of the most distinctive characteristics of this species, turning from a silvery gray calf to a dark brown/black subadult, and white adult. Their dorsal fin is one of the tallest in proportion to body length among any cetacean. They tend to inhabit deep, offshore waters (200–1000 m deep), warmer than 12°C. Risso’s dolphins dive deeply, feeding mainly on deep-water mesopelagic cephalopods, presumably at night. Age at sexual maturity is thought to be 8–10 years for females and 10–12 years for males. Locally, these animals show high-site fidelity and are encountered in relatively restricted areas. In the Azores a unique social structure was described as a “stratified community” where adults are grouped by age and sex classes. Males cluster in highly stable social units, whereas females form stable nurseries during a summer calving season. Risso’s dolphins have been killed during small-scale whaling operations in Japan, Sri Lanka, Taiwan, and the Faeroe Islands. They suffer from bycatch and noise pollution. Also recreational disturbance may have a long-term effect on coastal populations. The species is classified as “least concern” globally in the IUCN Red List.

One of Risso’s dolphin’s distinctive characteristics is the tendency to “lighten” with age due to the accumulation of unpigmented scars. These accumulated scars may provide an indication of age. Photographic skin recaptures gathered from 61 free-ranging animals over a period of 15 years were analyzed to develop a skin classification model in 6 skin stages. Classification of photographic skin captures following this model was tested by 15 experts and 13 nonexpert rankers, with a general probability of agreement of 79%. The duration of each skin stage was estimated using a statistical model based on the recorded dates in which individual animals were known to have entered and/or exited a given stage. A Bayesian approach was used to combine available photographic skin recapture data using expert knowledge as prior to predict the duration for each skin stage and thus the mean age at each stage. Results suggest that animals may live more than 45 years, which is in agreement with published information based on dental layers. The proposed skin stages can be correlated with reproduction, with the transition to stage 3 linked to the onset of maturity. Adult females are less scarified than males and were not observed in the whiter skin classes. The proposed skin stage model is noninvasive and easy to apply and could be a valuable tool in further studies of population structure and dynamics of Risso’s dolphins.

Each year, a phytoplankton spring bloom starts just north of the North Atlantic Subtropical Gyre, and then expands northwards across the entire North Atlantic. Here, we investigate whether the timing of the spring migration of baleen whales is related to the timing of the phytoplankton spring bloom, using 4 yr of dedicated whale observations at the Azores in combination with satellite data on ocean chlorophyll concentration. Peak abundances of blue whale Balaenoptera musculus, fin whale B. physalus, humpback whale Megaptera novaeangliae and sei whale B. borealis were recorded in April-May. The timing of their presence tracked the onset of the spring bloom with mean time lags of 13, 15, 15 and 16 wk, respectively, and was more strongly related to the onset of the spring bloom than to the actual time of year. Baleen whales were actively feeding on northern krill Meganyctiphanes norvegica in the area, and some photo-identified individuals stayed in Azorean waters for at least 17 d. Baleen whales were not observed in this area in autumn, during their southward migration, consistent with low chlorophyll concentrations during summer and autumn. Our results support the hypothesis that baleen whales track the secondary production generated by the North Atlantic spring bloom, utilizing mid-latitude areas such as the Azores as foraging areas en route towards their summer feeding grounds.

P>Behavioral responses of Risso's dolphins (Grampus griseus) to whale watching vessels were studied off Pico Island, Azores. Dolphin behavior was studied from a land-based lookout, enabling observations of groups in the absence and presence of vessels. The number of whale watching vessels showed a clear seasonal pattern, dividing the whale watching period into a low season and a high season. During the low season, Risso's dolphins rested mainly in the morning and afternoon. During the high season, Risso's dolphins rested less and did so mainly at noon, when the number of active vessels was lowest. Data analysis using a generalized additive mixed model indicated that this change in resting behavior was associated with vessel abundance. When more than five vessels were present, Risso's dolphins spent significantly less time resting and socializing. During the high season, this vessel abundance was exceeded during 20% of observation days. While we cannot be sure that the observed changes in behavior have fitness consequences for Risso's dolphins, reduced resting and socializing rates can have negative impacts on the build-up of energy reserves and on reproductive success. We suggest the adoption of precautionary management measures to regulate the timing and intensity of whale watching activities.

In this study, we present for the first time a model for the social structure of Risso’s dolphins ( Grampus griseus Cuvier, 1812). Over the period 2004–2006, 1028 Risso’s dolphins were identified at Pico island, Azores. Individuals sighted on 10 or more occasions were included in the analysis of social structure (n = 183). High resighting rates indicate strong site fidelity for at least part of the population. We found that individuals form stable, long-term bonds organised in pairs or in clusters of 3–12 individuals. Social structure is stratified based on age and sex classes, with strong associations between adult males and between adult females. We suggest that clusters form the basic units of Risso’s dolphin society. Thirteen pods consisting solely of adults, likely males, and 3 pods consisting of mother–calf pairs were identified. Males are organised in stable, long-term associations of varying size that occur throughout the complete range of behavioural states observed. For females, associations can be of similar strength, but the time scale may vary depending on the presence of nursing calves. As subadults, associations also occur (pair formation), but are less stable than those observed for adults. We propose a new model for Risso’s dolphin societies known as a stratified social organisation, which differs from the fission–fusion and matrilineal society models.

Contains fulltext : 49427.pdf (Publisher’s version ) (Closed access) BACKGROUND: Highly active antiretroviral therapy has been associated with lipodystrophy in adults. Much is unknown about its characteristics, especially in children. OBJECTIVE: To obtain an objective case definition of the lipodystrophy syndrome. METHODS: This was a cross-sectional study. One investigator rated clinical lipodystrophy. Body composition was measured using body mass index, skin fold thickness and circumference of arm, leg, waist and hip. Samples for human immunodeficiency virus (HIV)-1 RNA, CD4 cell count, fasting lipids and glucose variables were drawn. HIV-infected children with lipodystrophy were compared with HIV-infected children without lipodystrophy (controls). RESULTS: Thirty-four children were included: 28 controls, 2 nonassigned, and 4 with the lipoatrophic phenotype. Lipohypertrophy or mixed syndrome were not observed. All children with lipoatrophy were pubertal; they had used stavudine and didanosine longer. Children with lipoatrophy had significantly smaller arm and leg circumference, and their skin folds were thinner. The torso-to-arm ratio was 3 times higher in lipoatrophic children, but the difference did not reach significance. The waist-to-hip ratio was higher (P = 0.005). None of the laboratory values differed significantly between the two groups, but all children with lipoatrophy had an increased C-peptide level above the upper limit of normal. All children with lipoatrophy could be distinguised from controls by an increased C-peptide level, a waist-to-hip ratio z score of 1 standard deviation or higher and a sum of skin folds z score below -1 standard deviation. CONCLUSIONS: All children with lipoatrophy can be distinguished by using anthropometric measurements and C-peptide measurement in serum. This method is simple, readily available and inexpensive.

Calving can be a critical period for cetaceans. Areas providing security for vulnerable calves, and high food availability for lactating females can be critical habitats requiring specific conservation measures. Here, we test the hypothesis that calving and nursing habitat could be defined for Risso’s dolphins (Grampus griseus). We investigated the spatial and temporal preferences of this species around Pico Island, Azores, using data gathered from land-based surveys and dedicated at-sea observations between 2004 and 2007. We divided observed pods into three groups: (1) those with newborn and young calves, (2) those with older calves or juveniles and (3) those consisting only of adults or sub-adults. We analysed eco-geographical variables and incorporated them into a presence-only spatial distribution model to evaluate differences in habitat suitability among the groups. We identified 694 pods of Risso’s dolphins overall. On the 267 pods observed in the first and second groups, 136 calves or juveniles were identified, of which 22 were newborns. The peak of the calving season was between June and August. The pods with newborn calves were larger and closer to shore, whereas the other groups were more widely dispersed offshore. Our results support the definition of critical habitat areas for this species, but we suggest widening the geographical coverage for better mapping around the island and throughout the archipelago generally. Conservation measures can, nevertheless, be implemented immediately, in order to reduce human impacts on a vulnerable component of the Risso’s dolphin population. European Regional Development Fund (ERDF) COMPETE - Operational Competitiveness Programme.FCT - Foundation for Science and Technology, project "PEst-C/MAR/LA0015/2011". info:eu-repo/semantics/publishedVersion