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On 25 August 2021, a single female sperm whale (Physeter macrocephalus) was found stranded dead in Playa Tuxpan, Veracruz, Mexico. Skin biopsies were obtained and screened for the detection of various potentially pathogenic bacterial genera, using conventional polymerase chain reaction and sequencing of the positive amplicons. We recorded, for the first time, the presence of Vibrio paraheamolyticus in skin samples from P. macrocephalus in the Gulf of Mexico. Additionally, we discuss 29 records reporting strandings of sperm whales from six states of the Mexican Republic. Most of the records are concentrated in the Pacific Ocean. Our findings increase the inventory of bacteria reported in P. macrocephalus worldwide, summarising the knowledge of stranding events in sperm whale populations in Mexico.

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The remarkable sensory, motor, and cognitive abilities of mammals mainly depend on the neocortex. Thus, the emergence of the six-layered neocortex in reptilian ancestors of mammals constitutes a fundamental evolutionary landmark. The mammalian cortex is a columnar epithelium of densely packed cells organized in layers where neurons are generated mainly in the subventricular zone in successive waves throughout development. Newborn cells move away from their site of neurogenesis through radial or tangential migration to reach their specific destination closer to the pial surface of the same or different cortical area. Interestingly, the genetic programs underlying neocortical development diversified in different mammalian lineages. In this work, I will review several recent studies that characterized how distinct transcriptional programs relate to the development and functional organization of the neocortex across diverse mammalian lineages. In some primates such as the anthropoids, the neocortex became extremely large, especially in humans where it comprises around 80% of the brain. It has been hypothesized that the massive expansion of the cortical surface and elaboration of its connections in the human lineage, has enabled our unique cognitive capacities including abstract thinking, long-term planning, verbal language and elaborated tool making capabilities. I will also analyze the lineage-specific genetic changes that could have led to the modification of key neurodevelopmental events, including regulation of cell number, neuronal migration, and differentiation into specific phenotypes, in order to shed light on the evolutionary mechanisms underlying the diversity of mammalian brains including the human brain.

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An immature killer whale Orcinus orca found dead on the southeastern Brazilian coast had multiple bone proliferations: on the skull, vertebrae, hemal arches, and ribs. The bony formations were characterized as multiple osteochondromas, as defined by osteochondromatosis. The diagnosis was based on macroscopic and radiographic observations. These benign osseocartilaginous tumors affect young individuals and grow until skeletal maturity is achieved. Case reports of this condition, besides humans, include other mammals, with most reports for pets and domestic mammals such as cattle, and a report in a fossil canid (Hesperocyon) from the Oligocene. The etiology, diagnosis, developmental characteristics, and occurrence of osteochondromas are distinct among different species. This report describes the first case of multiple osteochondromas in a wild cetacean.

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Cetaceans originated in south Asia more than 50 million years ago (mya), from a small quadrupedal artiodactyl ancestor [1-3]. Amphibious whales gradually dispersed westward along North Africa and arrived in North America before 41.2 mya [4]. However, fossil evidence on when, through which pathway, and under which locomotion abilities these early whales reached the New World is fragmentary and contentious [5-7]. Peregocetus pacificus gen. et sp. nov. is a new protocetid cetacean discovered in middle Eocene (42.6 mya) marine deposits of coastal Peru, which constitutes the first indisputable quadrupedal whale record from the Pacific Ocean and the Southern Hemisphere. Preserving the mandibles and most of the postcranial skeleton, this unique four-limbed whale bore caudal vertebrae with bifurcated and anteroposteriorly expanded transverse processes, like those of beavers and otters, suggesting a significant contribution of the tail during swimming. The fore- and hind-limb proportions roughly similar to geologically older quadrupedal whales from India and Pakistan, the pelvis being firmly attached to the sacrum, an insertion fossa for the round ligament on the femur, and the retention of small hooves with a flat anteroventral tip at fingers and toes indicate that Peregocetus was still capable of standing and even walking on land. This new record from the southeastern Pacific demonstrates that early quadrupedal whales crossed the South Atlantic and nearly attained a circum-equatorial distribution with a combination of terrestrial and aquatic locomotion abilities less than 10 million years after their origin and probably before a northward dispersal toward higher North American latitudes. VIDEO ABSTRACT.

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The Ziphiidae (beaked whales) represent a large group of open-ocean odontocetes (toothed cetaceans), whose elusive and deep diving behavior prevents direct observation in their natural habitat. Despite their generally large body size, broad geographical distribution, and high species number, ziphiids thus remain poorly known. Furthermore, the evolutionary processes that have led to their extreme adaptations and impressive extant diversity are still poorly understood. Here we report new fossil beaked whales from the late Miocene of the Pisco Formation (southern Peru). The best preserved remains here described are referred to two new genera and species, the Messinian Chavinziphius maxillocristatus and the Tortonian Chimuziphius coloradensis, based on skull remains from two marine vertebrate-rich localities: Cerro Los Quesos and Cerro Colorado, respectively. C. maxillocristatus is medium sized retains a complete set of functional lower teeth, and bears robust rostral maxillary crests similar to those of the extant Berardius. By contrast, C. coloradensis is small and characterized by large triangular nasals and moderately thickened premaxillae that dorsally close the mesorostral groove. Both species confirm the high past diversity of Ziphiidae, the richest cetacean family in terms of the number of genera and species. Our new phylogenetic and biogeographical analyses depart markedly from earlier studies in dividing beaked whales into two major clades: the Messapicetus clade, which, along with other stem ziphiids, once dominated the southeastern Pacific and North Atlantic; and crown Ziphiidae, the majority of which are found in deep-water regions of the Southern Ocean, with possible subsequent dispersal both globally (Mesoplodon and Ziphius) and to the cooler waters of the northern oceans (Berardius and Hyperoodon). Despite this relatively clear separation, both lineages seem to follow similar evolutionary trends, including (1) a progressive reduction of dentition; (2) an increase in the compactness and thickness of the rostral bones; (3) similar changes in facial morphology (e.g., elevation of the vertex); and (4) an increase of body size. We suggest that these trends may be linked to a convergent ecological shift to deep diving and suction feeding.

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In contrast to dominant mode of ecological transition in the evolution of marine mammals, different lineages of toothed whales (Odontoceti) have repeatedly invaded freshwater ecosystems during the Cenozoic era. The so-called 'river dolphins' are now recognized as independent lineages that converged on similar morphological specializations (e.g., longirostry). In South America, the two endemic 'river dolphin' lineages form a clade (Inioidea), with closely related fossil inioids from marine rock units in the South Pacific and North Atlantic oceans. Here we describe a new genus and species of fossil inioid, Isthminia panamensis, gen. et sp. nov. from the late Miocene of Panama. The type and only known specimen consists of a partial skull, mandibles, isolated teeth, a right scapula, and carpal elements recovered from the Piña Facies of the Chagres Formation, along the Caribbean coast of Panama. Sedimentological and associated fauna from the Piña Facies point to fully marine conditions with high planktonic productivity about 6.1-5.8 million years ago (Messinian), pre-dating the final closure of the Isthmus of Panama. Along with ecomorphological data, we propose that Isthminia was primarily a marine inhabitant, similar to modern oceanic delphinoids. Phylogenetic analysis of fossil and living inioids, including new codings for Ischyrorhynchus, an enigmatic taxon from the late Miocene of Argentina, places Isthminia as the sister taxon to Inia, in a broader clade that includes Ischyrorhynchus and Meherrinia, a North American fossil inioid. This phylogenetic hypothesis complicates the possible scenarios for the freshwater invasion of the Amazon River system by stem relatives of Inia, but it remains consistent with a broader marine ancestry for Inioidea. Based on the fossil record of this group, along with Isthminia, we propose that a marine ancestor of Inia invaded Amazonia during late Miocene eustatic sea-level highs.

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Resumen Golfo Dulce es un estuario en forma de fiordo, localizado en el Pacífico Sur de Costa Rica. Este ecosistema marino-costero contiene una importante biodiversidad marina que incluye cetáceos. Este estudio describe la estructura de la comunidad de cetáceos en Golfo Dulce, sustentado en la diversidad de hábitats. Datos sobre avistamientos colectados en muestreos periódicos sistemáticos, han resultado en 943 registros (2005-2014≈3 490h≈64 533km) de siete especies de la familia Delphinidae, una Balaenopteridae y una especie de la familia Kogiidae. Se observa un gradiente en la diversidad de cetáceos desde la cuenca interna de Golfo Dulce hasta la zona de transición- oceánica en la entrada al Golfo. La dominancia se establece por la forma costera del delfín nariz de botella y el delfín manchado en la cuenca interna, mientras que T. truncatus junto con ballenas jorobadas migrantes ejercen la dominancia en el área del Umbral. El área transicional oceánica sostiene la mayor diversidad, dominada por especies de delfínidos de naturaleza piscívora, incluyendo la forma oceánica del delfín nariz de botella y la subespecie "Centroamericana" del delfín tornillo. Nosotros proponemos la hipótesis de una forma potencial particular del delfín manchado pantropical para Golfo Dulce, en contraste con S. attenuatta graffmani en aguas abiertas costeras del Pacífico Costarricense. El patrón de la estructura comunitaria de cetáceos se establece por la dinámica en uso de área por las especies presentes, lo cual debería ser considerado para el diseño de estrategias de manejo y conservación.

Abstract Golfo Dulce is a fiord-lilke embayment located in the southern Pacific of Costa Rica, this coastal-marine ecosystem harbors an important wealth in marine biodiversity, including cetaceans. In this study we describe the cetacean community of Golfo Dulce, in relation to the diversity of habitats constituting the seascape. Sighting data collected in periodic systematic surveys has yielded 943 records (2005-2014≈3 490h≈64 533km), of 12 species of cetaceans. A gradient of cetacean diversity is observed from the inner basin to the transitional-oceanic area at the entrance of the Gulf, with coastal bottlenose dolphin and spotted dolphin dominating the inner basin, and bottlenose dolphins and migratory humpback whales the sill area. Transitional oceanic habitat holds the greatest species diversity dominated by oceanic species, particularly piscivorous delphinids, including the off-shore form of bottlenose dolphins and the "Central American" spinner dolphin. We hypothesize the potential occurrence of a morphotype of pantropical spotted dolphins within Golfo Dulce, in contrast with S. attenuatta graffmani outside in open Pacific coastal waters. The pattern of cetacean community structure is established by the dynamic of area use by the species, which should be considered for the establishment of management and conservation strategies. Rev. Biol. Trop. 63 (2): 395-406. Epub 2015 June 01.

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The morphology and location of lymph nodes from seven species of Odontocetes, of both sexes and different age groups, were described. All animals were derived from stranding events along the North and Northeastern coasts of Brazil. After the identification of lymph nodes in situ, tissue samples were analyzed for light and electron microscopy. Vascular volume density (VVD) and vascular length density (VLD) were evaluated in the mesenteric lymph nodes. Lymph nodes occurred as solitary nodules or in groups, varying in shape and size. In addition to using the nomenclature recommended by Nomina Anatomica Veterinaria, new nomenclatures were suggested based on the lymph nodes topography. Lymph nodes were covered by a highly vascularized and innervated capsule of dense connective tissue, below which muscle fibers were observed, inconsistently, in all studied species. There was no difference in VLD among different age groups. However, VVD was higher in adults. Lymph nodes parenchyma was divided into an outer cortex, containing lymph nodules and germinal centers; a paracortical region, transition zone with dense lymphoid tissue; and an inner medulla, composed of small irregular cords of lymphatic tissue, blood vessels, and diffuse lymphoid tissue. Abundant collagen fibers were observed around arteries and arterioles. Germinal centers were more evident and developed in calves and young animals, being more discrete and sparse in adults. The morphology of lymph nodes in Odontocetes was typical of that observed in other terrestrial mammals. However, new groups of lymph nodes were described for seven species occurring in the Brazilian coast.

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The coastal spotted dolphin (Stenella attenuata graffmani) is one of the most common species of dolphin in inshore Pacific waters of Costa Rica. We conducted surveys in protected waters of the Papagayo Gulf, Costa Rica, to determine relative abundance of dolphins in relation to environmental variables. We used Generalized Additive Models to investigate the influence of a particular set of environmental factors and determine inter-annual trends in relative abundance. School sizes ranged from 1 to 50 individuals ( mean 9.95, SD=10.28). The number of dolphins increased linearly with water depth and transparency, and non-linearly with the dissolved oxygen concentration. High variability in the relative abundance occurred during the dry season (January-April). A previous study on this population found that high number of groups are involved in foraging activities during the dry season. Seasonal changes in relative abundance probably are associated with food availability, a variable that we did not measure. Understanding local resident populations may have important implications for conservation and management strategies. Large-scale studies may overlook variables affecting the abundance of local resident populations that may be detected with studies on a smaller scale such as this one.

El delfín manchado costero (Stenella attenuata graffmani) es una de las especies de delfines mas comunes de las aguas costeras del Pacifico de Costa Rica. En este estudio realizamos muestreos dentro de las aguas protegidas del Golfo de Papagayo para determinar su abundancia relativa en relación a características físico-químicas de su hábitat. Usamos modelos aditivos generalizados para investigar la influencia de un juego de variables ambientales y determinar tendencias inter-anuales en la abundancia relativa. El tamaño de los grupos varió de 1 a 50 individuos (promedio 9.95, SD=10.28). La cantidad de delfines aumentó linealmente con la profundidad y claridad del agua, y de forma no lineal con el oxígeno disuelto. Durante la época seca (enero-abril) encontramos la mayor variabilidad en la abundancia relativa. Un estudio anterior sugiere que una cantidad importante de delfines se alimenta aquí en la época seca. Ello sugiere que los cambios estacionales en la abundancia relativa de delfines manchados costeros podría estar asociada con la disponibilidad de alimento, una variable que no medimos pero que podría explicar la variación observada debido a la naturaleza productiva estacional del área. Los estudios de poblaciones locales y residentes pueden tener un mayor impacto en estrategias de conservación y manejo. Por lo general, los estudios a mayor escala geográfica pueden pasar por alto variables importantes que afectan la abundancia local de poblaciones residentes, las cuales pueden ser detectadas en estudios de menor escala como el presente.

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Despite the fact that heterochronic processes seem to be an important process determining morphological evolution of the delphinid skull, previous workers have not found allometric scaling as relevant factor in the differentiation within the genus Sotalia. Here we analyzed the skull ontogeny of the estuarine dolphin S. guianensis and investigate differential growth and shape changes of twocranialregions – the neurocranium and the face – in order to evaluate the relevance of cranial compartmentalization on the ontogeny of this structure. Our results show that, even though both cranialregions stop growing at adulthood, the face has higher initial growth rates than the neurocranium. The rate of shape changes is also different for both regions, with the face showing a initially higher, but rapidly decreasing rate of change, while the neurocranium shows a slow decreasing rate, leading to persistent and localized shape changes throughout adult life, a pattern that could be related to epigenetic regional factors. The pattern of ontogenetic shape change described here is similar to those described for other groups of Delphinidae and also match intra and interspecific variation found within the family, suggesting that mosaic heterochrony could be an important factor in the morphological evolution of this group.

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The aim of the present study was to describe the characteristics of Guiana dolphins (S. guianensis) group size and composition in the Paranaguá Estuarine Complex (25º 15' -25º 36' S and 48º 02'-48º 45' W), Paraná State, as well as to verify the existence of relationships between a given environmental variable (water depth, salinity, transparency and temperature) and group size. An area of around 124 km² was surveyed by boat from April 2006 to February 2008 in the following subsets of the estuary: Canal do Superagui (~28 km²), Pinheiros bay (~34 km²), part of Laranjeiras bay, which included the Guaraqueçaba sub-estuary (~38 km²), and part of the Mixture Section of the Paranaguá Estuarine Complex (~24 km²). In 45 survey days, a total of 147 hours were spent observing 286 groups of S. guianensis. Groups varied from two individuals to aggregations of up to 90 individuals (mean ± SD: 11.5 ± 14.4 individuals). Solitary individuals were seen only on five occasions (1.7 percent of all observations). Groups with calves (n = 247) represented 86.4 percent overall and were more common in all sub-areas when compared to groups without calves. Groups without calves were found in all sub-areas and were usually smaller and composed of up to 12 individuals. A usual group composition of 70 percent of adults and 30 percent of calves was observed considering all sub-areas and seasons. No correlations were found between group size and water temperature (Spearman's rank test, r = 0.0059, p = 0.9338), transparency (Spearman's rank test, r = 0.0597, p = 0.9333), depth (Spearman's rank test, r = 0.1421, p = 0.4698), and salinity (Spearman's rank test, r = -0.1938, p = 0.0665). While Guiana dolphin groups were seen in the entire surveyed area, group size varied significantly among the three main surveyed sub-areas (Kruskal Wallis, H2,196 = 29.85, p = 0.0000). Groups were larger in Laranjeiras bay and smaller in Canal do Superagui. The physical environment, risk ...(AU)

O objetivo do presente estudo foi descrever as características do tamanho e da composição de grupos do boto-cinza (S. guianensis) no Complexo Estuarino de Paranaguá (25º 15'-25º 36' S and 48º 02'-48º 45' O), Estado do Paraná, assim como de verificar a possível existência de relações entre uma dada variável ambiental (profundidade, salinidade, transparência e temperatura da água) e o tamanho de grupo. Uma área de aproximadamente 124 km² foi investigada com uso de barco a motor entre abril de 2006 e fevereiro de 2008 nas seguintes sub-áreas do estuário: Canal do Superagui (~28 km²), baía dos Pinheiros (~34 km²), parte da baía das Laranjeiras que incluiu o sub-estuário de Guaraqueçaba (~38 km²), e parte da Seção de Mistura do Complexo Estuarino de Paranaguá (~24 km²). Em 45 dias de investigação, um total de 147 horas foi empregado na observação de 286 grupos de S. guianensis. Numericamente os grupos variaram entre dois e 90 indivíduos (média ± DP: 11,5 ± 14,4 indivíduos). Indivíduos solitários foram observados em apenas cinco ocasiões (1,7 por cento de todas as observações). Grupos com filhotes (n = 247) representaram 86,4 por cento de todos os observados e foram mais comuns em todas as sub-áreas quando comparados com grupos sem filhotes. Grupos sem filhotes foram geralmente compostos por até 12 indivíduos e encontrados em todas as sub-áreas. Uma comum composição de grupo de cerca de 70 por cento de adultos e 30 por cento de filhotes foi observada considerando todas as sub-áreas e estações do ano. Não foram apontados correlações entre o tamanho de grupo e a temperatura (Teste de Rank de Spearman, r = 0,0059; p = 0,9338), a transparência (Teste de Rank de Spearman, r = 0,0597; p = 0,9333), a profundidade (Teste de Rank de Spearman, r = 0,1421; p = 0,4698), e a salinidade da água (Teste de Rank de Spearman, r = -0,1938; p = 0,0665). Enquanto grupos de botos-cinza foram observados ao largo de todo o estuário, seus tamanhos variaram significativamente ...(AU)

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The main objective of the present study was to describe the characteristics regarding interactions between Guiana dolphins, Sotalia guianensis and seabirds in feeding associations in two distinct areas of the Lagamar estuary, Brazil. Boat-based surveys directed towards photo-identification studies of S. guianensis were conducted in the Cananéia Estuary (CE) (25º 01' S and 47º 55' W) from July 2004 to March 2008, as well as in the Paranaguá Estuarine Complex (PEC) (25º 24' S and 48º 24' W) from April 2006 to February 2008. On all occasions when seabirds were observed engaging in multi-species feeding associations with S. guianensis, data on species involved and their numbers were gathered. From 435 observed groups of S. guianensis in the CE, 38 (8.7 percent) involved interactions with seabirds. In the PEC, from the 286 observed groups, 32 (11.2 percent) involved the mentioned interactions. The following seabirds were observed in feeding associations with S. guianensis: Fregata magnificens, Sula leucogaster, Phalacrocorax brasilianus, and Sterna sp. In the CE, S. leucogaster was more commonly observed in feeding associations with Guiana dolphins (χ2 = 22.84; d.f. = 3, p < 0.05), while in the PEC no differences were reported when comparing seabird species (χ2 = 5.78; d.f.=3, p = 0.1223). In the CE, feeding associations were significantly more frequent in inner waters (subset A0; χ2 = 9.52; d.f. = 2, p < 0.05), and in winter (χ2 = 12.46; d.f. = 1, p < 0.05). Within these events, 44.7 percent of the association groups were composed by more than one seabird species. Seasonality in feeding associations was also observed in the PEC (χ2 = 4.76; d.f. = 1, p < 0.05), with same patterns observed in the CE. Interactions were more frequent in inner waters of the Laranjeiras bay, PEC (χ2 = 11.65; d.f. = 2, p < 0.05). Within these events, 74.2 percent of the association groups were composed by more than one seabird species. ...(AU)

O objetivo principal do presente estudo foi de descrever as características a respeito das associações de alimentação entre o boto-cinza, Sotalia guianensis, e aves marinhas em duas áreas distintas do estuário do Lagamar, Brasil. Investigações efetuadas a partir de embarcação e direcionadas a estudos de foto-identificação de S. guianensis foram conduzidas no Estuário de Cananéia (EC) (25º 01' S e 47º 55' O) entre julho de 2004 e março de 2008, bem como no Complexo Estuarino de Paranaguá (CEP) (25º 24' S e 48º 24' O) entre abril de 2006 e fevereiro de 2008. Em todas as ocasiões em que aves marinhas foram observadas em associações de alimentação multiespecífica com S. guianensis, dados sobre as espécies envolvidas e seus números foram obtidos. Dos 435 grupos de S. guianensis observados no EC, 38 (8,7 por cento) envolveram interações com aves marinhas. No CEP, dos 286 grupos observados, 32 (11,2 por cento) envolveram as interações mencionadas. As seguintes aves marinhas foram observadas em associações de alimentação com S. guianensis: Fregata magnificens, Sula leucogaster, Phalacrocorax brasilianus, Sterna sp. No EC, S. leucogaster foi significativamente mais observada em associação de alimentação com o boto-cinza (χ2 = 22,84; g.l. = 3 p < 0,05), enquanto no CEP não foram observadas diferenças quando comparadas as aves marinhas (χ2 = 5,78; g.l. = 3, p = 0,1223). No EC, associações de alimentação foram significativamente mais freqüentes em águas internas (χ2 = 9,52; g.l. = 2, p < 0,05) e no inverno (χ2 = 12,46; g.l. = 1, p < 0,05). Dentre estes eventos, 44,7 por cento dos grupos de associação foram compostos por mais de uma espécie. Sazonalidade nas associações de alimentação também foi observada no CEP (χ2 = 4,76; g.l. = 1, p < 0,05), com os mesmos padrões observados para o EC. As interações foram mais freqüentes na baía das Laranjeiras, CEP (χ2 = 11,65; d.f. = 2, p < 0,05). Dentre estes eventos, 74,2 por cento ...(AU)

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The main objective of the present study was to describe the characteristics regarding interactions between Guiana dolphins, Sotalia guianensis and seabirds in feeding associations in two distinct areas of the Lagamar estuary, Brazil. Boat-based surveys directed towards photo-identification studies of S. guianensis were conducted in the Cananéia Estuary (CE) (25° 01' S and 47° 55' W) from July 2004 to March 2008, as well as in the Paranaguá Estuarine Complex (PEC) (25° 24' S and 48° 24' W) from April 2006 to February 2008. On all occasions when seabirds were observed engaging in multi-species feeding associations with S. guianensis, data on species involved and their numbers were gathered. From 435 observed groups of S. guianensis in the CE, 38 (8.7 percent) involved interactions with seabirds. In the PEC, from the 286 observed groups, 32 (11.2 percent) involved the mentioned interactions. The following seabirds were observed in feeding associations with S. guianensis: Fregata magnificens, Sula leucogaster, Phalacrocorax brasilianus, and Sterna sp. In the CE, S. leucogaster was more commonly observed in feeding associations with Guiana dolphins (χ2 = 22.84; d.f. = 3, p < 0.05), while in the PEC no differences were reported when comparing seabird species (χ2 = 5.78; d.f.=3, p = 0.1223). In the CE, feeding associations were significantly more frequent in inner waters (subset A0; χ2 = 9.52; d.f. = 2, p < 0.05), and in winter (χ2 = 12.46; d.f. = 1, p < 0.05). Within these events, 44.7 percent of the association groups were composed by more than one seabird species. Seasonality in feeding associations was also observed in the PEC (χ2 = 4.76; d.f. = 1, p < 0.05), with same patterns observed in the CE. Interactions were more frequent in inner waters of the Laranjeiras bay, PEC (χ2 = 11.65; d.f. = 2, p < 0.05). Within these events, 74.2 percent of the association groups were composed by more than one seabird species. ...

O objetivo principal do presente estudo foi de descrever as características a respeito das associações de alimentação entre o boto-cinza, Sotalia guianensis, e aves marinhas em duas áreas distintas do estuário do Lagamar, Brasil. Investigações efetuadas a partir de embarcação e direcionadas a estudos de foto-identificação de S. guianensis foram conduzidas no Estuário de Cananéia (EC) (25° 01' S e 47° 55' O) entre julho de 2004 e março de 2008, bem como no Complexo Estuarino de Paranaguá (CEP) (25° 24' S e 48° 24' O) entre abril de 2006 e fevereiro de 2008. Em todas as ocasiões em que aves marinhas foram observadas em associações de alimentação multiespecífica com S. guianensis, dados sobre as espécies envolvidas e seus números foram obtidos. Dos 435 grupos de S. guianensis observados no EC, 38 (8,7 por cento) envolveram interações com aves marinhas. No CEP, dos 286 grupos observados, 32 (11,2 por cento) envolveram as interações mencionadas. As seguintes aves marinhas foram observadas em associações de alimentação com S. guianensis: Fregata magnificens, Sula leucogaster, Phalacrocorax brasilianus, Sterna sp. No EC, S. leucogaster foi significativamente mais observada em associação de alimentação com o boto-cinza (χ2 = 22,84; g.l. = 3 p < 0,05), enquanto no CEP não foram observadas diferenças quando comparadas as aves marinhas (χ2 = 5,78; g.l. = 3, p = 0,1223). No EC, associações de alimentação foram significativamente mais freqüentes em águas internas (χ2 = 9,52; g.l. = 2, p < 0,05) e no inverno (χ2 = 12,46; g.l. = 1, p < 0,05). Dentre estes eventos, 44,7 por cento dos grupos de associação foram compostos por mais de uma espécie. Sazonalidade nas associações de alimentação também foi observada no CEP (χ2 = 4,76; g.l. = 1, p < 0,05), com os mesmos padrões observados para o EC. As interações foram mais freqüentes na baía das Laranjeiras, CEP (χ2 = 11,65; d.f. = 2, p < 0,05). Dentre estes eventos, 74,2 por cento ...

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The aim of the present study was to describe the characteristics of Guiana dolphins (S. guianensis) group size and composition in the Paranaguá Estuarine Complex (25° 15' -25° 36' S and 48° 02'-48° 45' W), Paraná State, as well as to verify the existence of relationships between a given environmental variable (water depth, salinity, transparency and temperature) and group size. An area of around 124 km² was surveyed by boat from April 2006 to February 2008 in the following subsets of the estuary: Canal do Superagui (~28 km²), Pinheiros bay (~34 km²), part of Laranjeiras bay, which included the Guaraqueçaba sub-estuary (~38 km²), and part of the Mixture Section of the Paranaguá Estuarine Complex (~24 km²). In 45 survey days, a total of 147 hours were spent observing 286 groups of S. guianensis. Groups varied from two individuals to aggregations of up to 90 individuals (mean ± SD: 11.5 ± 14.4 individuals). Solitary individuals were seen only on five occasions (1.7 percent of all observations). Groups with calves (n = 247) represented 86.4 percent overall and were more common in all sub-areas when compared to groups without calves. Groups without calves were found in all sub-areas and were usually smaller and composed of up to 12 individuals. A usual group composition of 70 percent of adults and 30 percent of calves was observed considering all sub-areas and seasons. No correlations were found between group size and water temperature (Spearman's rank test, r = 0.0059, p = 0.9338), transparency (Spearman's rank test, r = 0.0597, p = 0.9333), depth (Spearman's rank test, r = 0.1421, p = 0.4698), and salinity (Spearman's rank test, r = -0.1938, p = 0.0665). While Guiana dolphin groups were seen in the entire surveyed area, group size varied significantly among the three main surveyed sub-areas (Kruskal Wallis, H2,196 = 29.85, p = 0.0000). Groups were larger in Laranjeiras bay and smaller in Canal do Superagui. The physical environment, risk ...

O objetivo do presente estudo foi descrever as características do tamanho e da composição de grupos do boto-cinza (S. guianensis) no Complexo Estuarino de Paranaguá (25° 15'-25° 36' S and 48° 02'-48° 45' O), Estado do Paraná, assim como de verificar a possível existência de relações entre uma dada variável ambiental (profundidade, salinidade, transparência e temperatura da água) e o tamanho de grupo. Uma área de aproximadamente 124 km² foi investigada com uso de barco a motor entre abril de 2006 e fevereiro de 2008 nas seguintes sub-áreas do estuário: Canal do Superagui (~28 km²), baía dos Pinheiros (~34 km²), parte da baía das Laranjeiras que incluiu o sub-estuário de Guaraqueçaba (~38 km²), e parte da Seção de Mistura do Complexo Estuarino de Paranaguá (~24 km²). Em 45 dias de investigação, um total de 147 horas foi empregado na observação de 286 grupos de S. guianensis. Numericamente os grupos variaram entre dois e 90 indivíduos (média ± DP: 11,5 ± 14,4 indivíduos). Indivíduos solitários foram observados em apenas cinco ocasiões (1,7 por cento de todas as observações). Grupos com filhotes (n = 247) representaram 86,4 por cento de todos os observados e foram mais comuns em todas as sub-áreas quando comparados com grupos sem filhotes. Grupos sem filhotes foram geralmente compostos por até 12 indivíduos e encontrados em todas as sub-áreas. Uma comum composição de grupo de cerca de 70 por cento de adultos e 30 por cento de filhotes foi observada considerando todas as sub-áreas e estações do ano. Não foram apontados correlações entre o tamanho de grupo e a temperatura (Teste de Rank de Spearman, r = 0,0059; p = 0,9338), a transparência (Teste de Rank de Spearman, r = 0,0597; p = 0,9333), a profundidade (Teste de Rank de Spearman, r = 0,1421; p = 0,4698), e a salinidade da água (Teste de Rank de Spearman, r = -0,1938; p = 0,0665). Enquanto grupos de botos-cinza foram observados ao largo de todo o estuário, seus tamanhos variaram significativamente ...

Assuntos

RESUMO

The use of space by the resident population of estuarine dolphins (Sotalia guianensis) in Norte Bay, southern Brazil was studied by boat surveys between 2000 and 2003. Data such as the geographical position and group size was collected at 5-minute intervals using focal-group sampling. The distribution and seasonal and daily group home-ranges were estimated using a GIS (Geographic Information System) environment. The dolphins did not use the area homogeneously, restricting their activities to a well-defined area located in the western part of the bay, while the use of the eastern part was not observed. A discrepancy between the Environment Protection Area of Anhatomirim, created especially to protect this population and the distribution of the dolphins was observed. Seasonal group home-range varied both qualitatively and quantitatively among the four consecutive seasons analyzed. The dolphins tended to use a larger area in cold seasons, when apparently the abundance of major prey items is lower. Core areas of intense use were identified, and also varied seasonally. These core areas may be regarded as critical habitats and require special legislation and control. The mean daily group home-range did not differ statistically among seasons. The present study corroborates a spatially strict residency pattern of the estuarine dolphin in highly productive coastal ecosystems.

A utilização espacial pela população residente de botos-cinza, Sotalia guianensis, na Baía Norte de Santa Catarina, Sul do Brasil, foi estudada por meio de saídas de barco realizadas entre 2000 e 2003. Dados como posição geográfica (GPS) e tamanho de grupo foram obtidos utilizando-se o método de grupo focal. A distribuição e a área de vida diária e sazonal do grupo foram estimadas por um SIG (Sistema de Informações Geográficas). O uso do espaço pelos botos foi heterogêneo, restringindo suas atividades a uma área bem definida, localizada na parte oeste da baía, enquanto a utilização do lado leste não foi observada. Observou-se uma discrepância entre a distribuição dos botos e a Área de Proteção Ambiental de Anhatomirim, criada especialmente para proteger esta população. A área de vida sazonal do grupo variou tanto qualitativamente como quantitativamente nas quatro estações do ano consecutivas estudadas. Os botos tenderam a utilizar uma área maior nas estações frias do ano, quando a abundância de suas presas potenciais parece ser menor. Identificaram-se áreas de maior concentração de indivíduos, que também tiveram variação sazonal. Estas áreas de concentração podem ser consideradas hábitats críticos e exigem controle e legislação especial. Não houve uma diferença sazonal significativa nas áreas de vida diária do grupo de botos nas diferentes estações do ano estudadas. Os resultados deste trabalho apontam para um padrão de residência espacialmente restrita de S. guianensis em ecossistemas costeiros de grande produtividade.