ABSTRACT:We succinctly review and document new cases of diseases of the skin and the skeletal system and external traumata in cetaceans from Ecuador, Colombia, Peru, Chile, Argentina, Uruguay, Brazil, and Venezuela. The survey revealed 590 cases diagnosed with a significant pathology, injury or malformation on a total of 7635 specimens of 12 odontocete species examined or observed in . Tattoo skin disease (TSD), lobomycosis-like disease (LLD) and cutaneous diseases of unknown aetiology seem to be emerging in several populations. TSD was confirmed in eight species from the SE Pacific and SW Atlantic. LLD affected only inshore Tursiops truncatus but was found in four tropical countries, namely Colombia, Ecuador, Peru and Brazil. Lobomycosis was confirmed by histology in one male from the Tramandaí estuary, southern Brazil. All LLD-affected specimens were encountered in the vicinity of major ports and cities and a possible association with chemical or organic water pollution is suspected. Whitish velvety cutaneous marks associated with scars occurred in inshore T. truncatus, Sotalia guianensis and Pseudorca crassidens. Large, rounded lesions were seen in a Cephalorhynchus eutropia calf and a C. commersonii. Cutaneous wounds and scars as well as body traumata possibly related to net entanglements and boat collisions were observed in 73 delphinids and Phocoena spinipinnis. Traumatic injuries resulted in the partial or complete amputation and other disfiguring scars of appendages in 17 cases. Fractures of the skull, ribs and vertebrae thought to be caused by fisheries-related interactions or boat collisions were seen in single individuals of Delphinus capensis, Lagenorhynchus obscurus, T. truncatus, S. guianensis and Ziphius cavirostris. Prevalence of osteopathology in small cetaceans from Peru, Brazil and Venezuela ranged widely, from 5.4% to 69.1%. In four species from Peru, lytic cranial lesions were the most frequently observed disease (5.4%-42.9%), followed by hyperostosis and ankylosing spondylitis in offshore (31%, n=42) and inshore (15.4%, n=26) T. truncatus. Fractures and other bone traumata were present in 47.2% of 53 axial skeletons of S. guianensis from the northern Rio de Janeiro state (Brazil) in 1987-1998. A high prevalence (48.4%, n=31) of, apparently congenital, malformations of cervical vertebrae, observed in a 2001-2006 sample, may be explained by a hypothetical genetic bottleneck in this population. Malformations with deficient ossification would clearly increase susceptibility for fractures. This study demonstrates the utility of a continent-wide analysis to discern epizootiological trends more readily than any local study could provide. Secondly, it underscores the need for focussed research on the effects of human activities on the spread of diseases in cetaceans, particularly in near-shore populations that utilize highly degraded coastal habitats. RESUMEN:En este trabajo revisamos y documentamos brevemente nuevos casos de enfermedades de piel y de esqueleto, y traumas externos en cetáceos de Ec...

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Viddi, F. A., Hucke-Gaete, R., Torres-Florez, J. P., and Ribeiro, S. 2010. Spatial and seasonal variability in cetacean distribution in the fjords of northern Patagonia, Chile. – ICES Journal of Marine Science, 67: 959–970. Compared with other Chilean coastal areas, little is known about the diversity and distribution of cetaceans in northern Patagonian fjords. Between December 2000 and November 2001, surveys on platforms of opportunity were undertaken in southern Chile to evaluate species richness and the spatial and seasonal distribution of cetaceans. Nine species were recorded, blue, humpback, and minke whales, Peale's dolphin, Chilean dolphin, killer whale, false killer whale, bottlenose dolphin, and Cuvier's beaked whale. The pattern of cetacean distribution displayed significant seasonal differences, with most baleen whales (mysticetes) observed during late summer and autumn, and toothed cetaceans (odontocetes) mostly during spring. Generalized additive models, used to assess the spatial distribution of cetaceans, showed that mysticetes were distributed disproportionately along a north–south gradient, in open gulfs with oceanic influence, and close to shore. In contrast, odontocetes were observed mainly within narrow channels, areas with complex coastal morphology, peaking at different water depths. These findings, although from a single year of data, increase our understanding of habitat determinants of cetacean distribution in southern Chile. The results have the potential to be applied to coastal conservation and management in the region.

Fine-scale habitat selection of Chilean dolphins was studied between January and April 2002 through shore-based theodolite tracking in order to investigate the environmental and behavioural determinants of habitat use, and to evaluate the interactions between this species and aquaculture activities in Yaldad Bay, southern Chile. During 293.5 h of effort, movement and habitat selection patterns of dolphins exhibited a significantly concentrated use of only 21% of the entire study area. Correspondence analysis showed that shallow waters (5–10 m), proximity to coast and rivers were the most significant environmental parameters determining fine-scale dolphin distribution patterns, with foraging the most frequently observed activity. Aquaculture activities in the area were observed to affect dolphin habitat use patterns by restricting space available for biologically important dolphin behaviours.

1. Since 2000, an increasing number of humpback whale sightings have been recorded in northern Chilean Patagonia (mostly between 41.5 S and 44 S) from dedicated aerial and marine surveys and also opportunistic and land-based platforms during austral summer and autumn months.2. Based on local knowledge from the early years of coastal whaling suggesting the historic presence of humpback whales in the area, and more recent observations confirming feeding groups, mother-calf pairs, and philopatry, it is proposed that a proportion of the eastern South Pacific humpback whales consistently use the Chiloe-Corcovado region to feed and nurse their young.3. This mid-latitude area could be regarded as the northernmost feeding ground for humpback whales in South America, extending the previous known range some 1300 km north.4. These findings provide further evidence for alternative life-strategies other than traditional migration and highlight the importance of northern Patagonian fjords to resolve questions that are central for large baleen whale conservation and management such as the extent and characteristics of spatio-temporal habitat use and overlap with human activities.5. The need for future research on the migratory movements and population structure of this poorly understood population of humpback whales is emphasized, while an account is given of the threats they currently face.

BackgroundThe most traditional scheme for migration among baleen whales comprises yearly migrations between productive waters at high latitude summer feeding grounds and warmer waters at lower latitudes where whales calve and mate, but rarely feed. Evidence indicates, however, that large departures from this scheme exist among populations and individuals. Furthermore, for some populations there is virtually no information on migratory pathways and destinations. Such is the case of Chilean blue whales throughout the Eastern South Pacific; hence, the goal of this study was to assess its migratory behavior.MethodsDedicated marine surveys and satellite tagging efforts were undertaken during the austral summer and early autumn on blue whale feeding grounds off Chilean Northern Patagonia (CNP) during 2013, 2015 and 2016. Positional data derived from satellite tags regarding movement patterns and behavior were analyzed using Bayesian switching first-difference correlated random walk models.ResultsWe instrumented 10 CNP blue whales with satellite transmitters and documented individual variation in departure time, northbound migratory routes and potential wintering grounds. The onset of migration occurred from mid/late austral autumn to well into the austral winter. Blue whales moved in various directions, but ultimately converged toward a general NW movement direction along a wide corridor exceeding 2,000 km. Area-Restricted Search behavior was exhibited within fjords and channels of CNP and also South of Galapagos Archipelago (GA) and northern Peru, but never during migration. Interestingly, dive profiles for one whale that reached GA showed a sharp and consistent increase in depth north of 5°S and extreme deep dives of up to 330 m.DiscussionInformation derived from satellite tagged blue whales in this study is the first of its kind off the Eastern Southern Pacific. Our results provide valuable information on their migratory timing, routes and behavior on their northbound migration, particularly regarding the varied migratory plasticity for this particular population. Our results also highlight the first record of two complete migratory paths between CNP and GA and strengthen the hypothesis that GA waters correspond to a potential wintering destination for CNP blue whales. We further hypothesize that this area might be selected because of its biological productivity, which could provide feeding opportunities during the breeding season. Our results suggest that special efforts should be put forward to identify blue whale critical areas and understand key behavioral aspects in order to provide the basis for their conservation on a regional context (i.e., reducing potential ship strike and promote Marine Protected Area (MPA) implementation in Chile, Ecuador and Peru). Indeed, we suggest joint blue whale conservation efforts at the regional level in order to identify and determine potential threats and impacts and, most importantly, implement prospective management actions.

ABSTRACT1. In the face of environmental degradation, animals with limited plasticity are likely to be the most vulnerable. 2. Habitat selection by the threatened, endemic Chilean dolphin (Cephalorhynchus eutropia) was investigated in the northern Patagonian fjords, an area of extraordinary biological productivity.3. 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 4. 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.5. 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.

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