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RESUMO O catálogo de fotoidentificação da população de boto-cinza, Sotalia fluviatilis, da Baía de Sepetiba vem sendo formado desde 1994. São apresentados os dados preliminares do período entre abril de 1994 a junho de 1998, os quais indicam haver fidelidade ao habitat e algum grau de associação entre indivíduos. São também apresentados os diversos problemas de campo que levam a baixos índices de aproveitamento de fotos. O catálogo de fotoidentificação vem gerando informações que subsidiarão futuros estudos ecológicos, necessários à proposição de medidas que permitirão a conservação da espécie nesta baía.

RESUMO Os botos da baía de Sepetiba apresentam preferência por determinadas áreas para a pesca. Estas têm profundidade ≥10 m, sendo que durante o verão e o outono as áreas preferenciais são mais profundas do que durante o inverno e a primavera. Das ocorrências de pesca, 80,8% se deram dentro de uma faixa que se estende por 2,8 km para cada lado do canal dragado pelo Porto de Sepetiba. No inverno, outono e verão a ocorrência fora desta faixa foi baixa, mas durante a primavera esta foi de 73,3%. Tais preferências podem ser explicadas pelo hábito e padrão de distribuição das presas e por fatores climáticos.

• Fishers identify morphological and behavioral characteristics of river dolphins. • There is a partial overlap in fish species harvested by fishers and eaten by dolphins. • Costs of interaction with dolphins are estimated to three days of fishing income. • Most of interviewed fishers considered the dolphins to be beneficial for fisheries. • River dolphins are recognized for reducing fishing effort and protecting fishes. Understanding interactions between small-scale fishers and endangered dolphins is crucial for informing coexistence strategies. We investigated the perceptions and encounters of 123 Amazonian fishers in the Tapajós River (Brazil) with two endangered freshwater dolphins, Sotalia fluviatilis and Inia geoffrensis. Furthermore, 51 fishers self-documented 2,013 fish landings over one year. All interviewed fishers reported regular encounters with dolphins during fishing activities, with landings and interviews showing a partial overlap in fish species caught by fishers and cited as consumed by dolphins. Fishers highlighted that only I. geoffrensis disrupts fishing activities, causing gillnet damage and stealing fish from nets. To avoid interaction, fishers refrain from fishing an average of 3.7 times per month, potentially leading to 14.8 to 18.5 % decrease in total fish harvest. Economic losses were reported by 63 fishers, totaling an estimated US$ 50.3 ± 30.1 per month per fisher, which is equivalent to three days of fishing income. The estimated bycatch of dolphins was 10 per year across the studied area (71 % from I. geoffrensis). While 86 fishers considered dolphins beneficial, 62 viewed them as harmful. Fishers who fish more frequently are more likely to consider dolphins "good". The results revealed dolphins' positive contribution to fisheries by reducing efforts and safeguarding fish, while causing harm through gillnet damage. Negative perceptions are linked to individual economic losses, while positive perceptions stem from perceived collective benefits. By emphasizing dolphins' collective advantages in riverine communities, they can be a flagship species for conservation, leveraging their appeal and function as umbrella species for maintaining ecosystem functions, such as healthy fish stocks. [ABSTRACT FROM AUTHOR]

Quantifying the abundance of species is essential for their management and conservation. Much effort has been invested in surveys of freshwater dolphins in the Amazon basin but river dimensions and complex logistics limit replication of such studies across the region. We evaluated the effectiveness of using unmanned aerial vehicles (UAVs) for surveying two Amazon dolphin species, the tucuxi Sotalia fluviatilis and pink river dolphin Inia geoffrensis, in tropical rivers. In 2016 we conducted drone and visual surveys over 80 km of the Juruá River in Brazil. The aerial surveys provided higher accuracy than human observers in counting individuals detected in groups. Compared to estimates derived from visual surveys, the use of UAVs could provide a more feasible, economical and accurate estimate of Amazon river dolphin populations. The method could potentially be replicated in other important areas for the conservation of these species, to generate an improved index of river dolphin populations in the Amazon. [ABSTRACT FROM AUTHOR]

Coastal and freshwater cetaceans are particularly vulnerable due to their proximity to human activity, localized distributions, and small home ranges. These species include Sotalia guianensis, found in the Atlantic and Caribbean coastal areas of central and South America, and Sotalia fluviatilis, distributed in the Amazon River and tributaries. We investigated the population structure and genetic diversity of these 2 species by analyses of mtDNA control region and 8–10 microsatellite loci. MtDNA analyses revealed strong regional structuring for S. guianensis (i.e. Colombian Caribbean vs. Brazilian Coast, F ST = 0.807, ΦST = 0.878, P < 0.001) especially north and south of the Amazon River mouth. For S. fluviatilis, population structuring was detected between the western and eastern Amazon (i.e. Colombian Amazon vs. Brazilian Amazon, F ST = 0.085, ΦST = 0.277, P < 0.001). Haplotype and nucleotide diversity were higher for S. fluviatilis. Population differentiation was supported by analysis of the microsatellite loci (S. guianensis, northern South America vs. southern South America F ST = 0.275, Jost's D = 0.476, P < 0.001; S. fluviatilis, western and eastern Amazon F ST = 0.197, Jost's D = 0.364, P < 0.001). Most estimated migration rates in both species overlapped with zero, suggesting no measurable migration between most of the sampling locations. However, for S. guianensis, there was measurable migration in neighboring sampling locations. These results indicate that the small home ranges of these species may act to restrict gene flow between populations separated by relatively short distances, increasing the risk of extirpation of some localized populations in the future if existing threats are not minimized. [ABSTRACT FROM AUTHOR]

We present results of the first simultaneous visual and acoustic surveys for Amazon River dolphins (Inia geoffrensis) and tucuxi (Sotalia fluviatilis), undertaken in Yarinacocha Lagoon, Ucayali, Peru (length = 20 km, area = 12 km2). A total of 324 Sotalia observations and 44 Inia observations were recorded in boat-based transects. Based upon total survey effort, we estimated Sotalia had a mean density ± SE of 1.98 ± 4.6 ind km-2 and an overall abundance of 34 individuals (95% CI: 28 to 40). Average density for Inia was 0.2 ± 1.2 ind km-2 with overall abundance estimated at 3 individuals (95% CI: 0 to 8). Visual surveys observed more Sotalia individuals during earlier hours of the day and during the dry season. Preliminary acoustic surveys undertaken with C-POD passive acoustic monitoring devices indicated a diel pattern in detections of cetacean vocalization with more diurnal activity and with detections ceasing from midnight until 10:00 AM. This work highlights the possibility of monitoring both river dolphin species through visual and acoustic surveys to generate baseline information on abundance trends and distribution patterns in the Ucayali region, an area with high levels of human disturbance. [ABSTRACT FROM AUTHOR]

In 2005, three fishermen, with artisan fishing vessels and drift gillnets, accidentally captured around 200 dolphins between Vigia and Salinópolis in the Amazon River estuary. The dolphins died and they then prepared their vaginas and penises in order to sell them in the Ver-ao-Peso market in the city of Belem within the Brazilian state of Pará. We randomly sampled a minimal quantity of tissue of these sexual organs from 78 of these 200 dolphins and we determined the following results after sequencing 689 base pairs (bp) from the mitochondrial control region gene: (1) 96.15% (75/78) of these dolphins belonged to the species Sotalia guianensis. The other species detected were Steno brenadensis, Stenella coeruleoalba and Tursiops truncatus; (2) The levels of gene diversity found in this sample of S. guianensis were high (33 haplotypes, haplotype diversity of 0.917 and nucleotide diversity of 0.0045) compared to gene diversities found in other Brazilian S. guianensis locations; (3) All the population genetics methods employed indicated a clear population expansion in this population. This population expansion could have begun 400,000 years ago; (4) The haplotype divergence within this population could have begun around 2.1 millions of years ago (MYA), with posterior splits around 2.0–1.8 MYA, 1.7–1.8 MYA, 1–1.5 MYA, 0.6–0.8 MYA, 0.4–0.2 MYA and 0.16–0.02 MYA, all during the Pleistocene.

In this paper we present an analysis of the fifty S. fluviatilis feeding habits in the Amazonian Estuary. Animals were bycaught by the artisanal fishing fleet between 1996 and 2001. Feeding habits were analyzed by prey occurrence frequency (%F) and number percentage and stomachs contents preys similarity between marine and freshwater fishspecies present in the Amazonian Estuary. Thirteen fish species were identified (%F= 86.6), the most significant families were Sciaenidae (32%), Trichiuridae (26%) e Ariidae (16%), and four crustaceans species (%F=26). S. fluviatilis feeding habits did not differ bygender and in general, calves had higher prey diversity than juveniles and adults. The similarity was high (0.89) between estuarine S. fluviatilis feeding habits and the fishes speciespresent in the Amazonian Estuary when the environment is mostly marine.Objetivou-se descrever e analisar os hábitos alimentares de 50 golfinhos Sotalia fluviatilis capturados acidentalmente na frota pesqueira artesanal do Estuário Amazônico entre 1996 e 2001. As presas foram identificadas e calculadas a freqüência de ocorrência e numérica; testada a similaridade entre a diversidade de presas dos conteúdos e a diversidade de peixes marinhos e de água doce do estuário e, comparados os hábitos alimentares por sexo e categoria de maturidade. Ocorreram 13 espécies de peixes (86,6%) onde as famíliasSciaenidae (32%), Trichiuridae (26%) e Ariidae (16%) foram mais representativas e, quatro espécies de crustáceos (26%). A espécie não apresentou diferenças nos hábitos alimentares entre sexos, mas, os filhotes tiveram maior diversidade de presas que jovens e adultos.Finalmente, houve maior similaridade (0.89) entre a diversidade de presas de S. fluviatilis e as espécies de peixes quando o estuário apresenta características marinhas.

The objectives of this work were to reporte the helminths of the marine tucuxi, Sotalia fluviatilis (Cetacea: Delphinidae) in northern Rio de Janeiro State; and to check if the infestation rate varied with the host characteristics (sex and maturity) and year seasons. From 1989 to 2002, 80 marine tucuxis that were by-caught in fisheries were examined and four parasites were recorded: Braunina cordiformis, Anisakis typica, Halocercus brasiliensis and Nasitrema sp. The parasitism in the marine tucuxi corroborated its feeding habits and there were no infestation rate differences between males and females, youngs and adults, as well as between year seasons. This work reports for the first time the occurrence of the genus Nasitrema in the marine tucuxi.Os objetivos deste trabalho foram reportar os helmintos parasitas do tucuxi marinho, Sotalia fluviatilis, na costa norte do Estado do Rio de Janeiro; e checar se a taxa de infestação varia com as características do hospedeiro (sexo e maturidade) e estações do ano. Entre 1989 e 2002, 80 tucuxis marinhos capturados acidentalmente em pescarias foram examinados e quatro espécies de parasitas foram registradas: Braunina cordiformis, Anisakis typica, Halocercus brasiliensis e Nasitrema sp. O parasitismo no tucuxi marinho corrobora seu hábito alimentar e não foram constatadas diferenças nas taxas de infestação entre machos e fêmaes, jovens e adultos, assim como entre as estações do ano. Este trabalho reporta pela primeira vez a ocorrência do gênero Nasitrema no tucuxi marinho.

From July 2001 to June 2002, we recorded a total of 2h55min of Tucuxi Dolphin Sotalia fluviatilis vocalizations from Sepetiba Bay, Brazil (22º35'S-44º03'W). A total of 3350 whistles were analyzed quantitative and qualitatively and were divided into 124 types, by visual inspection of sonograms. The following parameters were measured: Initial Frequency, Final Frequency, Minimum Frequency, Maximum Frequency, Duration, Number of Inflections, Frequency at the Inflection Points, Frequency at 1/2, 1/4, and 3/4 of whistle duration, Presence of Frequency Modulation and Harmonics. Ascending type whistles (N=2719) were most common, representing 82% of the total. Dolphin behavior and average group size observed during recording influenced the whistle's quantitative and qualitative parameters. The results demonstrate the great diversity of whistles emitted and indicate a functional role of these vocalizations during the observed behaviors.

Pontoporia blainvillei (Gervais & D' Orbigny, 1844) and Sotalia fluviatilis (Gervais, 1853) have typically coastal habits and are sympatric in South-eastern Brazil. The purpose of this work was to record sightings and describe aspects concerning the behaviour of both species in this region, between 1993 and 1998. The sightings were accomplished by cruises and from a fixed point. Information provided by fishermen were also considered. In general, P. blainvillei was observed in all seasons of the year, up to five nautical miles away from the coast, up to 15 m deep and the groups comprised up to five specimens. The most part of the groups of S. fluviatilis, were observed in autumm and winter times and comprised up to 10 specimens. In about half of the sightings, the presence of calves and/or juveniles was noted. The cooperative (group) fishing was the foranging behaviour most frequently noted for S. fluviatilis.Pontoporia blainvillei (Gervais & D’Orgigny, 1844) e Sotalia fluviatilis (Gervais, 1853) possuem hábitos tipicamente costeiros e são simpátricas no Sudeste do Brasil. O objetivo deste trabalho foi registrar avistagens e descrever aspectos relacionados ao comportamento de ambas as espécies na região, entre 1993 e 1998. As avistagens foram realizadas através de cruzeiros e ponto fixo. Informações fornecidas por pescadores também foram consideradas. Em geral, P. blainvillei foi observada em todas as estações do ano, a até cinco milhas náuticas de distância da linha da costa e 15 m de profundidade e, os grupos eram formados por até cinco espécimens. A maior parte dos grupos de S. fluviatilis foi observada no período de outono e inverno e, era formada por até 10 espécimens. Em metade das avistagens, a presença de filhotes e/ou juvenis foi verificada. A pesca cooperativa (em grupo) foi o comportamento alimentar observado com maior freqüência para S. fluviatilis.

Pontoporia blainvillei (Gervais & D' Orbigny, 1844) and Sotalia fluviatilis (Gervais, 1853) have typically coastal habits and are sympatric in South-eastern Brazil. The purpose of this work was to record sightings and describe aspects concerning the behaviour of both species in this region, between 1993 and 1998. The sightings were accomplished by cruises and from a fixed point. Information provided by fishermen were also considered. In general, P. blainvillei was observed in all seasons of the year, up to five nautical miles away from the coast, up to 15 m deep and the groups comprised up to five specimens. The most part of the groups of S. fluviatilis, were observed in autumm and winter times and comprised up to 10 specimens. In about half of the sightings, the presence of calves and/or juveniles was noted. The cooperative (group) fishing was the foranging behaviour most frequently noted for S. fluviatilis.

The fishery for Calophysus macropterus, an Amazonian necrophagous catfish, is highly detrimental to river dolphins and caimans, which are deliberately killed for use as bait. In the Brazilian Amazon, this fishery has increased over the last decade, in spite of the rejection of scavenger fishes by Brazilian consumers. It was suspected that C. macropterus fillets were being sold in Brazilian markets, disguised as a fictitious fish (the "douradinha"). We collected 62 fillets from "douradinha" and other suspiciously named fish from 4 fish-processing plants sold at 6 markets in Manaus, in the Brazilian Amazon, and sequenced the cytochrome b gene to identify fillets to species. Sixty percent of fillets labeled "douradinha" or with other deceptive names were actually C. macropterus. Six other fish species of low commercial value were also found. The presence of dolphin tissue in the stomach contents of C. macropterus was confirmed by mtDNA control region sequencing. Our results formed the scientific basis for a moratorium on the fishing and fraudulent selling of C. macropterus, issued by the Brazilian Ministries of the Environment and Fisheries. Exposure of this fraud via the mass media can help end the illegal use of dolphins as bait in Brazil. [ABSTRACT FROM AUTHOR]

A major threat to river dolphins in Brazil is habitat loss and fragmentation as a result of the construction of hydroelectric dams. We examine the degree of overlap between the distributions of two river dolphin species (boto Inia geoffrensis and tucuxi Sotalia fluviatilis) and hydroelectric projects and provide an initial quantification of impacts. The locations of dams were overlaid onto a map of the known distributions of the dolphins. Two types of impacts were evaluated: population fragmentation and effects on prey. For each of these a binary score (for absence or presence) was assigned for each dam. The sum of all impact scores for each dam, in each of the three watersheds in which dolphins are found, including realized and potential impacts, was calculated as the impact index. Thirteen dams affect the distribution of I. geoffrensis (as could a further three dams under construction and seven planned), and three dams affect S. fluviatilis (as could three under construction and two planned). Overall, the impact index was higher for I. geoffrensis than for S. fluviatilis. The Araguaia–Tocantins and North Atlantic watersheds have higher impact index values than the Amazon watershed. Although some impacts of damming could not be considered in this study, our approach was a rapid initial risk assessment that provided an overall understanding of how river dolphins are and may be affected by hydroelectric projects in Brazil. Our method may be applicable to other freshwater cetaceans and species facing similar threats when information about impacts is incomplete. [ABSTRACT FROM PUBLISHER]

In 2005, three fishermen, with artisan fishing vessels and drift gillnets, accidentally captured around 200 dolphins between Vigia and Salinópolis in the Amazon River estuary. The dolphins died and they then prepared their vaginas and penises in order to sell them in the Ver-ao-Peso market in the city of Belem within the Brazilian state of Pará. We randomly sampled a minimal quantity of tissue of these sexual organs from 78 of these 200 dolphins and we determined the following results after sequencing 689 base pairs (bp) from the mitochondrial control region gene: (1) 96.15% (75/78) of these dolphins belonged to the species Sotalia guianensis. The other species detected were Steno brenadensis, Stenella coeruleoalba and Tursiops truncatus; (2) The levels of gene diversity found in this sample of S. guianensis were high (33 haplotypes, haplotype diversity of 0.917 and nucleotide diversity of 0.0045) compared to gene diversities found in other Brazilian S. guianensis locations; (3) All the population genetics methods employed indicated a clear population expansion in this population. This population expansion could have begun 400,000 years ago; (4) The haplotype divergence within this population could have begun around 2.1 millions of years ago (MYA), with posterior splits around 2.0-1.8 MYA, 1.7-1.8 MYA, 1-1.5 MYA, 0.6-0.8 MYA, 0.4-0.2 MYA and 0.16-0.02 MYA, all during the Pleistocene. [ABSTRACT FROM AUTHOR]

In the Western Brazilian Amazon, interactions of boto (Inia geoffrensis) and tucuxi (Sotalia fluviatilis) dolphins with fishing activities are common, but the prevalence of incidental/intentional catches is not known. This article describes incidental mortality events and intentional killing of I. geoffrensis and S. fluviatilis entangled in artisanal fishing gear and the opportunistic use of carcasses as bait. Between October 2010 and November 2011, surveys were conducted in waters of the lower Japurá River, between the Mamirauá and Amanã sustainable development reserves. In order to obtain information on interactions and to try to establish a stranding/entanglement response program (SERP), informal conversations were exchanged with local inhabitants (n = 174). Intense carcass-search surveys (n = 171) along the river in the four hydrological seasons (e.g., low, rising, high, and falling waters) were conducted, comprising a total of 1,197 h of sampling effort. Twenty-five dolphin-fishing interaction events were recorded (11 I. geoffrensis and 14 S. fluviatilis), 19 in 2011 and six in 2012 (through SERP). A total of 11 necropsies (three I. geoffrensis and eight S. fluviatilis) were performed. Four individuals (two I. geoffrensis and two S. fluviatilis) exhibited evidence of physical violence before death, and two (one I. geoffrensis and one S. fluviatilis) died in abandoned gillnets. Two intentional killing events of I. geoffrensis incidentally entangled for bait use in the piracatinga (Calophysus macropterus) fishery were reported by fishermen, while three carcasses (two I. geoffrensis and one S. fluviatilis) with gillnet marks were also used in that activity. At least six of the S. fluviatilis entanglement events occurred in fishing gear used for tambaqui (Colossoma macropomum) and pirapitinga (Piaractus brachypomus) (90/100-mm mesh-size gillnet), two of the most important commercial fish species in the Amazon Basin. As seasonal fishing constitutes the main income for riverine human populations, the negative reactions that cetacean presence causes to people could have a catalyst effect for the transition from "incidental capture" to "intentional capture and competitor removal." Law enforcement and precautionary measures through good fishing practices inside dolphin critical foraging areas should be taken together with fisheries' managers and fishermen to start to develop multiple-species management and ensure sustainable fishing practices. [ABSTRACT FROM AUTHOR]

Leptospirosis and brucellosis are zoonotic diseases with global distributions that represent severe hazards to humans and animals. We investigated exposure to Leptospira spp. and Brucella spp. in samples from Amazonian manatees Trichechus inunguis, Amazon river dolphins Inia geoffrensis, and a tucuxi Sotalia fluviatilis. The animals were free-ranging or undergoing in situ rehabilitation in the mid-Solimões River region, Brazilian Amazon. Serum samples from 19 Amazonian manatees were tested by microscopic agglutination test, Rose Bengal test, and 2-mercaptoethanol Brucella agglutination test. Antibodies against Leptospira spp. were detected in 63% of the manatees tested and serovar Patoc was considered the infecting serovar in all positive samples. Titers were generally low, indicating chronic exposure, but higher titers indicative of an active infection were detected in 3 animals. Anti-Brucella spp. antibodies were not detected. Tissue and/or body fluid samples from 12 Amazon river dolphins, a tucuxi, and 2 Amazonian manatees were investigated by multiplex PCR and bacteriology for Leptospira spp. and Brucella spp. All samples were negative. However, Enterococcus faecalis was isolated from uterine fluid, lymph node, and lung of 3 Amazon river dolphins. Bacillus spp. were isolated from milk and synovial fluid from 2 Amazon river dolphins and from a milk sample from 1 Amazonian manatee. Knowledge of the pathogens present in Amazonian manatees, Amazon river dolphins, and tucuxis is of great relevance to species conservation and environmental health. Although no clinical signs were noted, further research is needed to elucidate the clinical relevance of infection by Leptospira sp. serovar Patoc in Amazonian aquatic mammals.

Two distinct species have been recently recognized for the genus Sotalia: S. fluviatilis, occurring in the Amazon River basin, and S. guianensis, from Honduras (15°58′N and 85°42′W) to Santa Catarina State (Florianópolis, southern Brazil—27°35′S and 48°34′W). For the first time the sternum and the appendicular skeleton of the two species of the genus Sotalia are compared. A comparative osteological work was performed with marine samples (from the States of Ceará, north-eastern and Santa Catarina, southern regions of Brazil) and riverine samples (Amazonas State) in relation to metric characters (scapula, flipper and sternum). There was a clear distinction of two species in relation to postcranial skeleton in the morphometric analysis (canonical variate analysis) presented. The flipper and the glenoid cavity of the scapula were proportionally wider in the fluvial species. The sternum, however, was smaller in this species in relation to the maximum width of the manubrium. Nevertheless, this structure still needs to be further studied. [ABSTRACT FROM PUBLISHER]

Objetivou-se descrever e analisar os hábitos alimentares de 50 golfinhos Sotalia fluviatilis capturados acidentalmente na frota pesqueira artesanal do Estuário Amazônico entre 1996 e 2001. As presas foram identificadas e calculadas a freqüência de ocorrência e numérica; testada a similaridade entre a diversidade de presas dos conteúdos e a diversidade de peixes marinhos e de água doce do estuário e, comparados os hábitos alimentares por sexo e categoria de maturidade. Ocorreram 13 espécies de peixes (86,6%) onde as famílias Sciaenidae (32%), Trichiuridae (26%) e Ariidae (16%) foram mais representativas e, quatro espécies de crustáceos (26%). A espécie não apresentou diferenças nos hábitos alimentares entre sexos, mas, os filhotes tiveram maior diversidade de presas que jovens e adultos. Finalmente, houve maior similaridade (0.89) entre a diversidade de presas de S. fluviatilis e as espécies de peixes quando o estuário apresenta características marinhas.

Living in groups is usually driven by predation and competition for resources. River dolphins do not have natural predators but inhabit dynamic systems with predictable seasonal shifts. These ecological features may provide some insight into the forces driving group formation and help us to answer questions such as why river dolphins have some of the smallest group sizes of cetaceans, and why group sizes vary with time and place. We analyzed observations of group size for Inia and Sotalia over a 9 yr period. In the Amazon, largest group sizes occurred in main rivers and lakes, particularly during the low water season when resources are concentrated; smaller group sizes occurred in constricted waters (channels, tributaries, and confluences) that receive an influx of blackwaters that are poor in nutrients and sediments. In the Orinoco, the largest group sizes occurred during the transitional water season when the aquatic productivity increases. The largest group size of Inia occurred in the Orinoco location that contains the influx of two highly productive whitewater rivers. Flood pulses govern productivity and major biological factors of these river basins. Any threats to flood pulses will likely have an effect on the functionality of these ecosystems and the species living in them. [ABSTRACT FROM AUTHOR]

A β-N-Acetylhexosaminidase (EC 3.2.1.52) was purified from hepatic extracts of Sotalia fluviatilis, order Cetacea. The protein was purified by using ammonium sulfate fractionation and four subsequent chromatographies (Biogel A 1.5 m, Chitin, Deae-Biogel and hydroxyapatite resins). After these purification steps, the enzyme was purified 380.5-fold with an 8.4% yield. The molecular mass (10 kDa) was estimated by SDS–PAGE and MALDI-TOF analysis. A Km of 2.72 mM and Vmax 9.5 × 10−6 μmol/(min.mg) were found for this enzyme, determined by p-nitrophenyl-β- d-hexosaminide substrate digestion. Optimal pH and temperature for β-N-Acetylhexosaminidase activity were 5.0 and 60 °C, respectively. Enzyme activity was inhibited by sodium selenate (Na2SeO4), mercuric chloride (HgCl2) and sodium dodecyl sulfate (C12H25SO4Na), and activated by zinc, calcium, barium and lithium ions. Characterization of the β-N-Acetylhexosaminidase in Sotalia fluviatilis can be a basis for physiological studies in this species. [ABSTRACT FROM AUTHOR]

Dolphins of the genus Sotalia are found along the Caribbean and Atlantic coasts of Central and South America and in the Amazon River and most of its tributaries. At present, the taxonomy of these dolphins remains unresolved. Although five species were described in the late 1800s, only one species is recognized currently ( Sotalia fluviatilis) with two ecotypes or subspecies, the coastal subspecies ( Sotalia fluviatilis guianensis) and the riverine subspecies ( Sotalia fluviatilis fluviatilis). Recent morphometric analyses, as well as mitochondrial DNA analysis, suggested recognition of each subspecies as separate species. Here we review the history of the classification of this genus and present new genetic evidence from ten nuclear and three mitochondrial genes supporting the elevation of each subspecies to the species level under the Genealogical/Lineage Concordance Species Concept and the criterion of irreversible divergence. We also review additional evidence for this taxonomic revision from previously published and unpublished genetic, morphological, and ecological studies. We propose the common name “costero” for the coastal species, Sotalia guianensis ( Van Bénéden 1864 ), and accept the previously proposed “tucuxi” dolphin, Sotalia fluviatilis (Gervais, 1853), for the riverine species. [ABSTRACT FROM AUTHOR]

The Canane´ia estuary is an important biological area on the southeast coast of Brazil. In the past, it was impacted by both chlorinated pesticides and polychlorinated biphenyls (PCBs) due to its natural location. The marine tucuxi dolphin (Sotalia fluviatilis) is a top predator in this ecosystem and can be found year round in Canane´ia estuarine waters that represent an important nursing area for the species. This work investigated chlorinated compounds in the blubber of nine individuals from the Canane´ia estuary. Residue levels of DDTs (0.541–125 μg g−1 lipid wt.) were the highest, followed by PCBs (0.2–9.22 μg g−1 lipid wt.), mirex (0.014–0.312 μg g−1 lipid wt.), chlordanes (0.001–0.047 μg g−1 lipid wt.), HCHs (<0.003–0.044 μg g−1 lipid wt.), and HCB (n.d.−0.024 μg g−1 lipid wt.). The mean p,p′-DDE/Σ DDT ratio was approximately 0.8 and is indicative of the former DDT application in the study area. PCB contamination is suggested to be associated with atmospheric transport and relative proximity to the Cubata˜o industrial complex—the most important along the Brazilian coast. Low levels of HCHs and HCB can be attributed to their high volatility in tropical environments. Concentrations of organochlorines in the blubber of marine tucuxis from the Canane´ia estuary were lower than levels found in small cetacean species from developed countries, where the input of these compounds was considerably greater than in Brazil. At extremes, male dolphins can present DDT burden several orders of magnitude higher than females. Despite the high levels of total DDT found in males, the major detected compound was p,p′-DDE which is considered to be of low toxicity. [Copyright &y& Elsevier]

O objetivo do presente estudo foi descrever um grupo de lesões causadas por enredamento em Sotalia fluviatilis capturado acidentalmente por rede de pesca em 23 de julho de 1995 no Norte do Estado do Rio de Janeiro (21º37'S-041º01'W), Sudeste do Brasil. O espécime apresentou lesões laceradas na pele e no tecido subcutâneo ao redor da extremidade posterior do rostro. Fios de náilon foram encontrados associados às lesões. Lesões ósseas e nos dentes foram também observadas na área subjacente e afetaram as maxilas, pré-maxilas e mandíbulas. As lesões provavelmente foram causadas por enredamento não-letal em aparelho de pesca. Anomalias no padrão de camadas de crescimento dos dentes lesados, entre a terceira e a sexta camada, sugerem que esta lesão ocorreu aos três anos de idade. Os dados indicam que encontros não-letais com redes de pesca podem causar sérios problemas de saúde em pequenos cetáceos. Esta é a primeira descrição de lesão crônica em S. fluviatilis relacionada a pescarias.

Research on fishing activity at Atafona village, in Northern Rio de Janeiro, Brazil (21°35'S), was carried out between 1987-96 for the purpose of relating it to the accidental capture of small cetaceans and of estimating the relationship between fishing activity and the diet of small cetaceans. Data on fishing operations were obtained at the cold storage plants management, from interviews with fishermen and personal observations. The most representative fishing resources were Xyphopenaeus kroyeri, Micropogonias furnieri, Carcharhinus plumbeus, C. acronotus,and Rhizoprionodon porosus. Gillnets are responsible for the accidental capture of small cetaceans in the region, mainly Pontoporia blainvillei and Sotalia fluviatilis (marine form). Four types of gillnets that are used on the region ("minjuada", "sarda", "caçoá" and "pescadinha") were dangerous to these species because they are placed in their preferred habitat. There is no competition between fishermen and small cetaceans due to the selection in the capture of commercialized fishesInvestigação sobre a atividade pesqueira na localidade de Atafona, Norte do Rio de Janeiro, Brasil (21º25`S), foi conduzida entre 1987-96 com o objetivo de relacioná-la com a captura acidental e a dieta dos pequenos cetáceos. Dados sobre as operações pesqueiras foram obtidos na administração dos entrepostos de pesca, através de entrevistas com pescadores e observações pessoais. Os recursos pesqueiros mais representativos foram Xyphopenaeus kroyeri, Micropogonias furnieri, Carcharhinus plumbeus, C. acronotus, and Rhizoprionodon porosus. As redes de espera são responsáveis pela captura acidental de pequenos cetáceos na região, principalmente de Pontoporia blainvillei e Sotalia fluviatilis (forma marinha). Quatro tipos de redes de espera que são usadas na região ("minjuada", "sarda", "caçoá" and "pescadinha") foram mais perigosas para essas espécies pois são colocadas no seu hábitat preferencial. Não existe competição entre pescadores e pequenos cetáceos devido à seleção na captura dos peixes comercializados.