Understanding temporal patterns of marine mammal occurrence is useful for establishing conservation strategies. We used a 38 yr-long dataset spanning 1976 to 2013 to describe temporal patterns and trends in marine mammal strandings along a subtropical stretch of the east coast of South America. This region is influenced by a transitional zone between tropical and temperate waters and is considered an important fishing ground off Brazil. Generalized Additive Models were used to evaluate the temporal stranding patterns of the most frequently stranded species. Forty species were documented in 12,540 stranding events. Franciscana (n = 4,574), South American fur seal, (n = 3,419), South American sea lion (n = 2,049), bottlenose dolphins (n = 293) and subantarctic fur seal (n = 219) were the most frequently stranded marine mammals. The seasonality of strandings of franciscana and bottlenose dolphin coincided with periods of higher fishing effort and strandings of South American and subantarctic fur seals with post-reproductive dispersal. For South American sea lion the seasonality of strandings is associated with both fishing effort and post-reproductive dispersal. Some clear seasonal patterns were associated with occurrence of cold- (e.g. subantarctic fur seal) and warm-water (e.g. rough-toothed dolphin) species in winter and summer, respectively. Inter-annual increases in stranding rate were observed for franciscana and South American fur seal and these are likely related to increased fishing effort and population growth, respectively. For subantarctic fur seal the stranding rate showed a slight decline while for bottlenose dolphin it remained steady. No significant year to year variation in stranding rate was observed for South American sea lion. The slight decrease in frequency of temperate/polar marine mammals and the increased occurrence of subtropical/tropical species since the late 1990s might be associated with environmental changes linked to climate change. This long-term study indicates that temporal stranding patterns of marine mammals might be explained by either fishing-related or environmental factors.

The common bottlenose dolphin, Tursiops truncatus, is one of the world's best known cetaceans. However, there are few studies on the activity budgets and distribution of this species along the Brazilian coast. This study aimed at describing and quantifying the behavioral activity of T. truncatus in the Patos Lagoon Estuary, Rio Grande do Sul state, southern Brazil (ca. 32 o 09'S, 52 o 05'W). The study area was divided into three sub-areas according to the proximity to the estuary mouth. The behavioral data were gathered every 5 minutes following a focal group sampling approach. A total of 34 boat surveys were conducted between December 2001 and January 2003, totaling 66.95h of direct observation and 672 records of behavioral activities. The first 15 minutes of each group encounter were discarded to avoid the influence of the boat approach on dolphin behavior. The most observed behavior was feeding (37.64%), followed by traveling (29.17%), travel-feeding (21.87%), socializing (5.8%), milling (4.33%) and resting (1.19%). There was not a significant difference among the frequencies of commonly observed behaviors: feeding, traveling and travel feeding (p>0.05, t-test for proportions). Dependence between activity and season was detected in subareas I and II (p<0.001; Pearson's X 2 ), as well as an association between activity and sub-areas (p<0.001; Pearson's X 2 ). Regarding group size, 56.41% of the activities recorded were carried out by groups of 1 to 3 dolphins, 31.63% from 4 to 6, 10.25% from 7 to 10, and 1.71% by groups with more than 10 individuals. This study confirmed the importance of the Patos Lagoon Estuary as an area for bottlenose dolphins to conduct their daytime activities, in particular feeding.Resumo: O boto ou golfinho nariz-de-garrafa, Tursiops truncatus, é um dos cetáceos mais bem conhecidos no mundo. Entretanto, existem poucos estudos sobre a atividade comportamental e distribuição desta espécie ao longo da costa brasileira. O objetivo deste trabalho foi descrever e quantificar os comportamentos de T. truncatus no Estuário da Lagoa dos Patos, Rio Grande do Sul, Brasil (32°09'S, 52°05'W). A área de estudo foi dividida em três subáreas de acordo com a proximidade da desembocadura do estuário. Os dados comportamentais foram registrados a cada 5 minutos seguindo a metodologia de amostragem de grupo focal. Um total de 34 saídas foram conduzidas entre dezembro de 2001 e janeiro de 2003, totalizando 66,95h de observações diretas e 672 registros de atividades comportamentais. Os primeiros 15 minutos de cada grupo encontrado foram descartados a fim de evitar qualquer influência da aproximação da embarcação no comportamento dos animais. O comportamento mais observado foi alimentação (37,64%), seguido por deslocamento (29,17%), deslocamento com alimentação (21,87%), socialização (5,8%), milling (4,33%) e descanso (1,19%). Não houve diferença significativa entre as freqüências de comportamento mais comuns: alimentação, deslocamento e deslocamento com alimentação (p>0.05, teste t para proporções). Detectou-s...

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A região do “Albardão”, no litoral do extremo sul do Brasil, é reconhecida por sua expressiva produtividade pesqueira, resultante da dinâmica dos processos oceanográficos regionais, que garantiu o desenvolvimento de uma diversificada frota pesqueira, que abastece os parques industriais de Rio Grande (RS) e Itajaí (SC) e sustenta parte da frota pesqueira de Santos (SP), além de grande contingente de embarcações do exterior. Esta região também sustenta grande biodiversidade e muitas espécies de peixes, aves, mamíferos e tartarugas marinhas ameaçadas de extinção, pela captura acidental ou direcionada por meio da intensa atividade pesqueira. Dentre este conjunto de conflitos socioambientais, destaca-se a recente proposição de criação de uma Unidade de Conservação (UC) marinha na região. Caso a implantação desta UC ocorra conforme os planos oficiais, prevê-se o incremento nos conflitos, em função da restrição de acesso das comunidades de pesca artesanal às áreas e aos recursos pesqueiros e à supressão da atividade pela frota industrial em grandes áreas marinhas adjacentes. Esta opção provocaria contundente rejeição social e política aos esforços conservacionistas, dificultando a efetiva implantação da UC proposta, especialmente devido aos casos similares, implantados sem considerar os direitos de acesso dos usuários às suas áreas de histórica atuação. De modo a subsidiar este processo quanto às suas melhores opções socioambientais, foi organizada intensiva revisão bibliográfica e análise documental das publicações disponíveis sobre o tema e a região; procedeu-se à elaboração de um Sistema de Informações Geográficas e à estruturação dos cenários conceituais preditivos sobre os potenciais desdobramentos da proposta (sem a implantação da UC; com a implantação da UC como Parque Nacional; com a implantação como um Mosaico de UCs). Ao final, procedeu-se à argumentação do custo-benefício da opção entendida como a mais coerente (o Mosaico de UCs), desdobrando-a em dois subconjuntos, de menor (a) e maior (b) abrangência e relevância socioambiental.

Aim Urbanization leads to rapid changes in ecosystem structure and function. Wetlands on university campuses under urbanization pressure could be used as case studies of multidisciplinary aquatic research and good environmental practices promoting sustainability. Methods A paleolimnological study was undertaken in a semi-artificial lake on a university campus in southern Brazil to trace historical impacts and ecological changes back to the mid-1970s through complementary approaches: historical data, nutrients, δ13C and δ15N stable isotopes, diatoms, microplastics and associated microbial community analysis. Results The eutrophication process started to intensify after the lake was used for nocturnal roosting by waterbirds, and especially after the establishment of constructions along the margins with septic tank sanitary sewage, which eventually spilled and leached into the lake. Over decades, we identified a limnological hypertrophication process leading to recurrent cyanobacterial blooms and massive macrophyte proliferation coupled with changes in isotopic ratios and algal occupation with several transitions between shallow lake alternative states. Such a limnological process has resembled the paleolimnological eutrophication trends and isotopic changes in sedimentary organic matter. The microplastic deposition was detected as a proxy for the intensification of urbanization, especially during the construction of the University facilities. Conclusions The combined use of paleolimnological and historical limnological data represents a powerful approach for inferring both natural and cultural impacts on the lake, and identifying management strategies based on such scientific information.