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Cephalorhynchus eutropia and Lagenorhynchus australis. Examples of observed (—) versus expected (---) net squared displacement and lower 25% and upper 95% ( ... ) CIs and corresponding trajectories plotted within the survey area for 3 dolphin groups demonstrating different movement types: (A) Chilean dolphin group ID9 classified as 'resident'; (B) Peale's dolphin group ID24 classified as 'correlated random walker'; and (C) Peale's dolphin group ID6 classified as 'transient'. I: beginning of trajectory
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Animal movement is a central topic in ecology, as movements are crucial to habitat selection, foraging and spatial population ecology. Movement is a primary mechanism coupling animals to their environment, as organisms respond to environmental heterogeneity at different spatio-temporal scales. The fjord system in southern Chile is highly heterogene...
Citations
... Common diving-petrel LC - regarding the ecology of marine mammals and the marine systems on which they depend in this region, this gap is slowly being filled by systematic studies that have reported on the distribution, abundance, habitat modeling, behavioral and movement patterns, as well as the ecological determinants of these different processes [9,10,35,39,40,43,[98][99][100]. These studies demonstrated that seasonal and spatial primary productivity is an important indicator of the meso-scale distribution and movement patterns of whales. ...
Chilean Patagonia boasts 100,627 km of coastline, including approximately 40,050 islands and numerous fjords and channels, which generate a high degree of geomorphological and hydrographic complexity and make it one of the largest mega-estuarine environments on Earth. These characteristics, among others, generate structurally and functionally unique marine ecosystems, as well as biodiversity hotspots. In this chapter we perform a comprehensive literature review and highlight the use of marine mammals and seabirds as focal species to guide conservation initiatives aimed at minimizing anthropogenic impacts as well as safeguarding the ecosystem integrity of Patagonia as a climate refuge. Given their characteristics as ecologically relevant umbrella, indicator, and sentinel species, we suggest that focal species are highly useful in guiding the prioritization of management and conservation initiatives to achieve world-class conservation standards in Chilean Patagonia.
... The more specialized habitat preference of Chilean dolphins is accompanied by small local population sizes, small home ranges, high residency patterns, and little variation in habitat-use patterns on a decadal scale (Heinrich, 2006;Viddi et al., 2011;Heinrich et al., 2019), traits shared among species of the genus Cephalorhynchus (Elwen et al., 2006;Rayment et al., 2011;Brough et al., 2019;Coscarella et al., 2022). The only previous estimate of Chilean dolphin abundance was provided by Heinrich (2006), who estimated that (Dawson et al., 2004). ...
Assessing distribution and abundance patterns for rare species is challenging yet imperative, considering the extant, potentially hazardous, anthropogenic activities. In particular, the poorly studied Chilean dolphin (Cephalorhynchus eutropia) exhibits an extremely patchy distribution and low densities, co-occurring with the intensive aquaculture industry in Southern Chile, among other anthropogenic activities.
The distribution and abundance patterns of Chilean dolphins were assessed in the entire Northern Chilean Patagonia. A hierarchical species distribution model was fitted to data from line transect surveys using distance sampling techniques and environmental variables derived from topographic features and oceanographic models. A second version of this model used a joint-likelihood approach to incorporate presence–pseudoabsence data for improving parameter estimation. Spatial predictions arising from these models were used to evaluate the relative probability of a dolphin encountering vessels from the local, predominantly aquaculture fleet.
The results show that using a joint-likelihood approach drastically reduced uncertainty in the parameters controlling the effect of covariates and in the total abundance estimates. This model estimated an overall low abundance (median 2,225.8; 95% CI 1,340–3,867) for this species in the region, and indicates their preference for shallow, sheltered bays and inner channels, near river mouths, where low salinity is expected. The highest probabilities of dolphin–vessel interactions were found on the eastern coast of Chiloe Big Island, coinciding with the largest number of aquaculture concessions in the area.
Considering that the overall population of the Chilean dolphin is expected to be in the low thousands, that suitable habitat for the species is highly restricted, and that the species is facing increasing anthropogenic impacts, with some areas undergoing or planning major expansions in development, the results provided here should be considered in management plans for extant marine protected areas, and in the evaluation of current International Union for Conservation of Nature (IUCN) and national conservation categories for the species.
... En total resultaron 35 referencias bibliográficas publicadas que contienen registros de las especies dentro del territorio regional, las cuales procedían de diferentes fuentes: 13 artículos en revistas científicas internacionales (Van Waerebeek et al. 1991;Hucke-Gaete et al. 2004b;Buchan et al. 2010;Olavarría et al. 2010;Viddi et al. 2010;Aguayo-Lobos et al. 2011;Viddi et al. 2011;Medina-Vogel et al. 2013;Boop 2014;Buchan et al. 2014;Cárdenas 2014;Acevedo et al. 2016;Bocconcelli et al. 2016) ...
Integración de datos de biodiversidad para la educación y el turismo: mamíferos marinos nativos en la región subantártica de Aysén, Chile Resumen: La ecorregión subantártica de Chile, que incluye a las regiones administrativas de Aysén y Magallanes, se caracteriza por su alto grado de endemicidad y la singularidad de sus especies dada su proximidad a la Antártida. En particular, la zona de canales y fiordos subantárticos con más de 100 000 km de costa y una geomorfología compleja, es una de las zonas estuarinas más grandes del mundo y alberga una diversidad elevada de mamíferos marinos, superior en todo caso a los valores registrados en zonas más templadas del sur de Sudamérica. Sin embargo, los registros de datos de biodiversidad en esta zona austral son aún escasos y, cuando existen, se publican exclusivamente en revistas especializadas inaccesibles para las comunidades locales. Esta falta de información dificulta el diseño de estrategias de conservación a escala regional y el desarrollo socioeconómico local, como puede ser el desarrollo de un turismo especializado en avistamientos de cetáceos o experiencias similares a otras re-giones del cono sur. En este contexto y con el fin de visibilizar e integrar los registros existentes de mamíferos marinos en repositorios de información, se plantea una revisión exhaustiva de la literatura publicada sobre este grupo de organismos en la región de Aysén. Se recopilaron un total de 484 registros correspondientes a avistamientos de mamíferos marinos presentes en la región de Aysén entre 1852 y 2016, a partir de bibliografía publicada en revistas especializadas, libros y documentos técnicos. Taxonómicamente, se recopilaron un total de 28 especies, 6 pertenecientes al Orden Carnivora (Familias Mustelidae, Otariidae y Phocidae) y 22 al Orden Cetacea (Familias Balaenidae, Balaenopteridae, Delphinidae, Hypero-odontidae, Phocoenidae y Physeteridae). Esta recopilación de datos se inició con el Sistema de Información sobre Biodiversidad para Aysén (SIB-Aysén) y se continuó con el Laboratorio Abierto de Ciencias Subantárticas. Eventualmente será complementada con las observaciones de ciudadanos asociadas al SIB-Aysén. Se discute la relevancia de integrar los conjuntos de datos de biodiversidad en repositorios abiertos como herramienta im-prescindible para diseñar políticas de conservación y promover en la medida de lo posible iniciativas de desarrollo económico basado en el conoci-miento de su patrimonio natural. Palabras clave: avistamiento de ballenas; bases de datos sobre biodiversidad; GBIF; Patagonia chilena; Región subantártica / Biodiversity data integration for education and tourism: native marine mammals in the sub-Antarctic region of Aysén, Chile. Abstract: The sub-Antarctic ecoregion of Chile, which includes the administrative regions of Aysén and Magallanes, is characterized by its high degree of endemicity and the uniqueness of its species given its proximity to Antarctica. In particular, the sub-Antarctic channels and fjords, with more than 100 000 km of coastline and a complex geomorphology, is one of the largest estuarine zones in the world and harbors a high diversity of marine mammals that is in any case higher than the values recorded in more temperate areas of southern South America. However, biodiversity data records in this southern zone are still scarce and, when they do exist, they are published exclusively in specialized journals inaccessible to local communities. This lack of information hinders the design of conservation strategies on a regional scale and local socioeconomic development, such as the development of tourism specialized in whale watching or experiences similar to other regions of the southern cone. In this context and in order to visualize and integrate the existing records of marine mammals in information repositories, an exhaustive review of this group of organisms is proposed. A total of 484 records or sightings of marine mammals present in the Aysén region between 1852 and 2016 were compiled from bibliography published in specialized journals, books and technical documents. A total of 28 species, 6 belonging to the Order Carnivora (Families Mustelidae, Otariidae and Phocidae) and 22 to the Order Cetacea (Families Balaenidae, Balaenopteridae, Delphinidae, Hyperoodontidae, Phocoenidae and Physeteridae). This data collection began with the Biodiversity Information System for Aysén (SIB-Aysén) and continued with the Open Laboratory for Sub-Antarctic Sciences. Eventually it will be complemented with the observations of citizens associated with the SIB-Aysén. The relevance of integrating biodiversity datasets into open repositories as an essential tool for designing conservation policies and promoting, as far as possible, economic development initiatives based on knowledge of their natural heritage is discussed. ASOCIACIÓN ESPAÑOLA DE ECOLOGÍA TERRESTRE Ecosistemas 31(3):2410 [Septiembre-Diciembre 2022] https://doi. > Recibido el 1 de junio de 2022-Aceptado el 07 de noviembre de 2022 <
... Besides, groups are distinctive enough in the field, sometimes separated by several hundreds of meters from each other. This sampling methodology was already used for modeling habitat use of dusky dolphins in Nuevo Gulf [43] and for Chilean and Peale's dolphin movement pattern analysis [47]. It was also used for evaluating the effect of tour boats on dolphin behavior by modeling behavior sequences by Markov chains in dusky [24,48] and common dolphins [26]. ...
... This hypothesis remains untested but further modelling could be done in order to test it, developing more mechanistic models of movement-that allow for simulation of movement, for instance. The study of movement pattern, within a CRW framework, was applied to other two dolphin species, the Peale's and the Chilean dolphin, in southern Chile [47]. The lack of fit of these dolphin species to CRW models was interpreted as these species do not undertake movement patterns typical of dispersal, but rather have a tendency to reside in the same locations. ...
Movement is a key factor in the survival and reproduction of most organisms with important links to bioenergetics and population dynamics. Animals use movement strategies that minimize the costs of locating resources, maximizing energy gains. Effectiveness of these strategies depends on the spatial distribution, variability and predictability of resources. The study of fine-scale movement of small cetaceans in the pelagic domain is limited, in part because of the logistical difficulties associated with tagging and tracking them. Here we describe and model the fine-scale movement patterns of two pelagic dolphin species using georeferenced movement and behavioral data obtained by tracking dolphin groups on board small vessels. Movement patterns differed by species, group sizes and seasons. Dusky dolphin groups moved shorter distances when feeding and longer distances when traveling whereas the common dolphin did the same only when they moved in large groups. In summer, both dolphins cover longer distances in a more linear path, while in winter the movement is more erratic and moving shorter distances. Both species of dolphins prey on small pelagic fishes, which are patchily distributed and show seasonal variability in school sizes and distribution. However, dusky dolphins rely on anchovy to a larger extent than common dolphins. In Nuevo Gulf, anchovy shoals are smaller and separated by shorter distances in winter and dusky dolphins´ movement pattern is consistent with this. Dusky and common dolphins are impacted by tourism and fisheries. Further modelling of movement could be inform spatial based management tools.
... However, the underlying principle of spatial selectivity of coastal cetaceans is more likely due to the provision of ecosystem service(s) from the specific preferred spatial feature instead of the feature itself (Allen et al., 2001;Hastie et al., 2003b;Viddi et al., 2011). For example, the higher occurrence of humpback dolphin along a river-bank is likely due to the aggregation of prey during certain tidal periods . ...
... Moreover, the apparent differences in the diurnal patterns of occurrence between various sites in Hong Kong may imply site-specific attractiveness to humpback dolphins. Therefore, patterns seen elsewhere in other studies should be treated cautiously and not applied to Hong Kong without prior research and critical scrutiny (Allen et al., 2001;Ribeiro et al., 2007;Viddi et al., 2011). ...
... However, the underlying principle of spatial selectivity of coastal cetaceans is more likely due to the provision of ecosystem service(s) from the specific preferred spatial feature instead of the feature itself (Allen et al., 2001;Hastie et al., 2003b;Viddi et al., 2011). For example, the higher occurrence of humpback dolphin along a river-bank is likely due to the aggregation of prey during certain tidal periods . ...
... Moreover, the apparent differences in the diurnal patterns of occurrence between various sites in Hong Kong may imply site-specific attractiveness to humpback dolphins. Therefore, patterns seen elsewhere in other studies should be treated cautiously and not applied to Hong Kong without prior research and critical scrutiny (Allen et al., 2001;Ribeiro et al., 2007;Viddi et al., 2011). ...
The world's largest population of Indo-Pacific humpback dolphins (Sousa chinensis) in the Pearl River Estuary is exposed to some of the world's greatest concentration of anthropogenic threats, much of it due to the region's rapid urbanisation and industrialisation in recent decades. By assessing behavioural responses of humpback dolphins to long-term and large-scale environmental change in Hong Kong, and short-term but frequent behavioural disturbance due to unregulated dolphin-watch tourism, this study investigates humpback dolphins as a model system of a coastal delphinid in the coastal seas of the Anthropocene.
Field surveys were conducted between 2011 and 2014 to identify humpback dolphins’ distribution pattern. Resource selection function was applied to model the dolphin's habitat selection process and quantify their long-term habitat preference. The results indicate that humpback dolphins display a heterogeneous pattern in habitat selectivity that is conditional to distinctive sets of key factors at different spatial scales. By using Landsat data and historic archives, and by quantifying a cumulative habitat loss over the past 40 years, this study reveals that during that time the natural shoreline providing critical ecological functions to humpback dolphins in Hong Kong has been drastically reduced. Occurrence probabilities reconstructed for the time-periods prior to major habitat alterations, and occurrence probabilities projected into future years (when all currently planned projects are to be completed) indicate a major drop of habitat use by the dolphins in areas neighbouring reclamation sites. All current Marine Protected Areas (MPAs) for humpback dolphin conservation are already affected by the ongoing environmental change and this will intensify in the future.
Shore-based scan-sampling surveys were conducted between 2013 and 2014 to identify a distribution pattern of the dolphins at one of their main feeding areas in Hong Kong. With year-round sightings, the dolphins used this area selectively at different seasons and time of day. Only a small portion of the area was used as feeding location, within a narrow range of distances from shore, demonstrating a clear pattern of spatio-temporal fine-scale habitat selection that has not been accounted for in all current conservation actions in Hong Kong.
Behavioural responses of humpback dolphins to small-scale dolphin-watch operations were investigated by tracking the dolphins' movement and recording fine-scale changes in the movement parameters. Analyses show that movement patterns of the dolphins, distinctive between behavioural states, were significantly altered by the presence of dolphin-watch boats. Multivariate models reveal that the disturbance by dolphin-watch operations can be seen as an external factor affecting the dolphins’ spatial decisions. Consequently, an appropriate regulatory mechanism is needed to manage the dolphin-watch tourism and minimise its impact on the target species.
In summary, this study quantifies humpback dolphins’ response to large long-term and short-term chronic anthropogenic impacts, and indicates that various human activities affect the dolphins' daily behaviour and habitat selection. The conservation actions that are currently in place are ineffective in protecting humpback dolphins from man-made threats and will not be effective in preserving their habitat in the long-term. This implies serious ecological consequences and an urgent need for science-based and habitat-oriented conservation strategy.
... Our hazard function also assumes an exponential form for the spatial and temporal decay of infectiousness and does not explicitly account for individual migration. There have been more complex models of dolphin movement but these have been based on explicit tracking of individuals [47,48]. Since our stranding data contain no information on how animals move during the epidemic, we have adopted the most parsimonious framework to describe dispersal that can provide biologically interpretable results in broad agreement with existing knowledge and data. ...
Morbilliviruses cause major mortality in marine mammals, but the dynamics of transmission and persistence are ill understood compared to terrestrial counterparts such as measles; this is especially true for epidemics in cetaceans. However, the recent outbreak of dolphin morbillivirus in the northwestern Atlantic Ocean can provide new insights into the epidemiology and spatio-temporal spread of this pathogen. To deal with uncertainties surrounding the ecology of this system (only stranded animals were observed), we develop a statistical framework that can extract key information about the underlying transmission process given only sparse data. Our self-exciting Poisson process model suggests that individuals are infectious for at most 24 days and can transfer infection up to two latitude degrees (220 km) within this time. In addition, the effective reproduction number is generally below one, but reaches 2.6 during a period of heightened stranding numbers near Virginia Beach, Virginia, in summer 2013. Network analysis suggests local movements dominate spatial spread, with seasonal migration facilitating wider dissemination along the coast. Finally, a low virus transmission rate or high levels of pre-existing immunity can explain the lack of viral spread into the Gulf of Mexico. More generally, our approach illustrates novel methodologies for analysing very indirectly observed epidemics.
... The region holds an outstanding set of distinct ecological communities and is a hotspot for cetacean diversity (Hucke-Gaete et al., 2006) and in particular is habitat for the endemic but little known Chilean dolphin (Cephalorhynchus eutropia) (Goodall, 1994;Viddi et al., 2010, Viddi and. Chilean dolphins are highly localized and have restricted local and fine-scale movements (Heinrich, 2006;Viddi et al., 2011) and thus might be especially susceptible to the effects of extensive habitat modification as a result of coastal development, intensive salmon farming and associated activities. Chilean dolphins are listed as 'Near Threatened' and limited abundance data suggest that they are in decline (Reeves et al., 2013). ...
... Chilean dolphin habitat preference is clearly influenced by rivers and tidal regimes (Heinrich, 2006;Ribeiro et al., 2007;Viddi et al., 2011). In a related study, Ribeiro et al. (2007) showed that Chilean dolphins from Chiloe Island not only had a preference for shallow waters (5-10 m), but that foraging was most frequently observed in proximity to the coast and river mouths suggesting that those features might be of importance to Chilean dolphins. ...
In the face of environmental degradation, animals with limited plasticity are likely to be the most vulnerable.
Habitat selection by the threatened, endemic Chilean dolphin ( Cephalorhynchus eutropia ) was investigated in the northern Patagonian fjords, an area of extraordinary biological productivity.
Generalized additive models were undertaken to assess the ecological determinants of Chilean dolphin spatial distribution and habitat selection. Data were collected from dedicated fine‐scale marine surveys conducted during the austral summer of 2007, 2008 and 2009
Modelling techniques provide strong support for Chilean dolphins aggregating in distinct hotspots, preferring shallow water, near rivers and in areas where the influence of tidal regime is greater.
The preference for coastal shallow waters and river influenced habitats by Chilean dolphins puts them in direct conflict with a growing aquaculture industry and hydropower projects. The models predict areas of high densities of Chilean dolphins and excluding these areas from new developments would provide clear protection to the habitat most important to this poorly known endemic Chilean species.
Copyright © 2015 John Wiley & Sons, Ltd.
... In the last five years, there has been progress in the information generated on both Chilean and Peale's dolphins, though there are still important gaps in knowledge and therefore an urgent need for research on these species. Most research until now has principally focused on distribution, habitat selection and patterns of movement (Viddi & Lescrauwaet, 2005;Heinrich, 2006;Ribeiro et al., 2007;Viddi et al., 2010Viddi et al., , 2011, while other aspects have been overlooked, including behavioural patterns. This is mainly because some researchers mistakenly believe that data on behaviour have little applicability to understanding ecological processes or because these data have little contribution to make towards the conservation and management of species. ...
... The lack of temporal patterns in behaviour for both Chilean and Peale's dolphins may be a response to relatively constant prey availability, also suggested for bottlenose dolphins (Hansen & Defran, 1993) and dusky dolphins, Lagenorhynchus obscurus , in Argentina. This may be the case for Peale's dolphins, as they rely strongly on kelp beds (Viddi & Lescrauwaet, 2005;Viddi et al., 2011), which may sustain a more constant prey availability. In addition, a lack of temporality may be also be explained by patterns of prey availability other than circadian, such as tidal cycle, which is not constant during the day and changes from one day to the next. ...
... This pattern, which may be an important functional component of Chilean dolphins, may be associated with the spatial distribution of prey. The association between travelling and feeding, in which animals move rapidly over areas that are poor in resources and stay longer in feeding grounds, has been widely reported in cetaceans and other species (Bergman et al., 2000;Mårell et al., 2002;Stevick et al., 2002;Austin et al., 2006;Viddi et al., 2011;Degrati et al., 2012). Peale's dolphins, on the other hand, showed higher probabilities of transition from milling to socializing, resting to travelling and travelling to resting. ...
Assessing the behavioural patterns of animals is an increasingly important field in conservation biology, as it may assist in the prediction of how animals respond to rapid changes in the environment. Comparing the behavioural patterns of sympatric species can also give insights into the mechanisms that allow similar species to coexist. We undertook dolphin group follows in order to quantify the behavioural patterns of the sympatric Chilean and Peale's dolphins in southern Chile. Markov chains showed that these species differed significantly in time allocated to each of the five different behavioural states, but travelling was the most frequent behavioural state observed for both species. Six (out of 25) behavioural transitions were found to be different between species. In addition, group size and group dispersion were highly associated with specific behavioural states. Larger groups were more likely to socialize, while small groups were more likely to rest. For both species resting was mostly observed in tight groups, while foraging/feeding and travelling were related to intermediate group dispersion. Socializing differed between species, occurring in tight groups for Peale's dolphins and dispersed groups for Chilean dolphins. Overall, there were significant differences in behavioural patterns between the two species. These dissimilarities may represent evidence of different strategies (i.e. habitat use patterns and foraging) these two species employ which allow them to coexist. The information generated in this study will contribute to the development of better predictive models on how animals may respond to a changing environment and to the potential effects of human induced activities.
