Foram amostrados 17 trechos de riachos com 100 m de extensão, todos de ordem igual ou menor a três, ao longo de ambas as margens do canal principal do Rio Paranapanema, SP e PR. O ponto médio de cada trecho foi georreferenciado via satélite com receptor GPS e o uso de metodologia padronizada de coleta de dados ambientais e peixes (baseada principalmente na pesca elétrica), possibilitou a obtenção das seguintes informações em cada local: 1) composição taxonômica da ictiofauna e contribuição, em termos de número de indivíduos e biomassa, de cada espécie para a ictiofauna local como um todo; 2) documentação fotográfica de espécimes representativos de cada espécie coletada com sua coloração natural; 3) descrição de cada ambiente coletado, com ilustrações fotográficas coloridas, e seus principais parâmetros bióticos e abióticos. No total foram coletados 3.683 exemplares, pertencentes a seis ordens, 16 famílias, 37 gêneros e 52 espécies, com biomassa total de 16,8 kg. Das espécies coletadas, aproximadamente 36% pertencem a ordem Siluriformes, 36% a Characiformes, 11% a Gymnotiformes, 10% a Perciformes, 4% a Cyprinodontiformes e 2% a Synbranchiformes. As espécies mais abundantes em termos de número de indivíduos foram Astyanax altiparanae (15,2%) e Astyanax sp. 1 (12,3%); aquelas com maior biomassa foram A. altiparanae (28%) e Geophagus brasiliensis (13%). A composição da ictiocenose em termos de abundância e biomassa por família indica a predominância expressiva de Characidae, seguida por Loricariidae, Pimelodidae e Cichlidae. Dentre os trechos amostrados, o trecho 14 (24 espécies) e o 13 (cinco espécies), apresentaram a maior e a menor riqueza em espécies, respectivamente, coincidindo com os valores obtidos para o índice de diversidade específica de Shannon-Wienner (H´= 0,99 e 0,32, respectivamente). A riqueza média encontrada foi de 11 espécies por trecho de riacho. Na estimativa de riqueza por extrapolação para o conjunto total de riachos amostrados na bacia do rio Paranapanema, obtivemos um valor de 69 espécies (erro padrão igual a quatro) indicando ser necessário um esforço amostral adicional moderado para atingir a assíntota da curva. Das 52 espécies coletadas, oito (aproximadamente 15% do total) são seguramente novas, cinco (aproximadamente 10% do total) possuem “status” taxonômico ainda indefinido, enquanto outras três (aproximadamente 6% do total) são espécies introduzidas. Analisando a estrutura trófica e espacial da ictiocenose estudada, as 10 espécies numericamente dominantes nos riachos estudados dividem-se, em ordem decrescente de importância numérica, em quatro guildas: onívoros nectônicos; invertívoros bentônicos; perifitívoros; e onívoros bentônicos. Uma chave de identificação para todas as espécies de peixes coletadas durante este estudo é fornecida ao final deste trabalho.

The Abrolhos Bank (eastern Brazil) encompasses the largest and richest coral reefs of the South Atlantic. Coral reef benthic assemblages of the region were monitored from 2003 to 2008. Two habitats (pinnacles' tops and walls) were sampled per site with 3–10 sites sampled within different reef areas. Different methodologies were applied in two distinct sampling periods: 2003–2005 and 2006–2008. Spatial coverage and taxonomic resolution were lower in the former than in the latter period. Benthic assemblages differed markedly in the smallest spatial scale, with greater differences recorded between habitats. Management regimes and biomass of fish functional groups (roving and territorial herbivores) had minor influences on benthic assemblages. These results suggest that local environmental factors such as light, depth and substrate inclination exert a stronger influence on the structure of benthic assemblages than protection from fishing. Reef walls of unprotected coastal reefs showed highest coral cover values, with a major contribution of Montastraea cavernosa (a sediment resistant species that may benefit from low light levels). An overall negative relationship between fleshy macroalgae and slow-growing reef-building organisms (i.e. scleractinians and crustose calcareous algae) was recorded, suggesting competition between these organisms. The opposite trend (i.e. positive relationships) was recorded for turf algae and the two reef-building organisms, suggesting beneficial interactions and/or co-occurrence mediated by unexplored factors. Turf algae cover increased across the region between 2006 and 2008, while scleractinian cover showed no change. The need of a continued and standardized monitoring program, aimed at understanding drivers of change in community patterns, as well as to subsidize sound adaptive conservation and management measures, is highlighted.

Eighteen 100 m long streams stretches, none of an order higher than three, were sampled in three tributaries (six stream stretches sampled in each one) of the left margin of the main channel of Rio Grande (Rios Turvo, Pardo and Sapucaí) in the State of São Paulo, southeastern Brazil. Each stream stretch had its midpoint located with a GPS satellite receiver and had its fish fauna sampled via a standardized environmental data and fish collection methodology (primarily utilizing electrofishing) with the aim of providing the following information about each stream: 1) the taxonomic composition of the fish fauna and the contribution of each species in that stream in terms of both number of individuals and biomass; 2) a photographic documentation of the live coloration of representative specimens of each collected species; and 3) the description of each sampled environment, with colored photographic illustrations and details of the main biotic and abiotic parameters. Overall 3,070 fishes were collected, belonging to six orders, 18 families, 44 genera, and 64 species, with a total biomass of 14.3 kg. Of the collected species, approximately 50% were Characiformes, 26.5% Siluriformes, 11% Perciformes, 6% Gymnotiformes, 5% Cyprinodontiformes, and 1.5% Synbranchiformes. The most abundant species in terms of total number of individuals were Astyanax altiparanae (17.4%) and Hypostomus ancistroides (9%); the species with the largest biomasses were Astyanax altiparanae (35%) and Geophagus brasiliensis (9%). In terms of abundance and biomass collected for each family, the Characidae was clearly the predominant family followed by the Loricariidae, and Cichlidae. Among the sampled stream stretches, locality SG6 with 26 species and locality PG4 with three species yielded the highest and lowest richness in terms of species numbers, respectively. This coincides with the values obtained for the ShannonWiener index of specific diversity (H´ = 1.08 and 0.26, respectively). The median species richness for all streams stretches was 12. In the species richness estimate by extrapolation for all 18 sampled stream stretches, a value of 93 species was obtained (with a standard error of three) indicating the need for an additional moderate sampling effort to reach the asymptote of the curve. Of the 64 collected species, four (approximately 6% of the total) are clearly new to science and seven other species (approximately 11% of the total) are of indefinite taxonomic status and require further analysis. Two of the captured species are certainly introduced (approximately 3% of the total). Analysis of the trophic and spatial structure of the studied fish fauna indicates that the 10 numerically dominant species in the sampled streams can be grouped, based on published data, into five guilds that are in decreasing order of numeric importance: nektonic omnivores; benthic invertivores; periphytovores; algivores and benthic omnivores. An identification key for all the species of fish collected during this study is provided.

Diplectrum formosum (the sand perch), Diplectrum radiale (the aquavina), Epinephelus marginatus (the dusky grouper) and Mycteroperca acutirostris (the comb grouper) are four sympatric serranid of remarkable ecological and commercial importance. This study investigated the feeding of these four species in the São Sebastião Channel, São Paulo State (southeastern Brazil), comparing their diet, habitat utilization and morphological features related to foraging. These four serranids are opportunistic visual predators that use a total of nine different tactics to capture their preys, feed mostly on crustaceans during the day and twilight, and keep stationary and quiescent at night. The ecomorphological study was conducted to test its predictive value to infer lifestyles. It was verified that such analysis should be used carefully and must be complemented by field observations. Although morphologically and behaviorally very similar, D. formosum and D. radiale showed different preferences to the substratum type used by large individuals, which are exclusively sit-and-wait predators. On the other hand, E. marginatus displayed more sedentary habits than M. acutirostris, the most versatile predator from the studied species. The studied species of Diplectrum and E. marginatus can be regarded as benthic serranids, while M. acutirostris could be viewed as a nektobenthic species.Diplectrum formosum, Diplectrum radiale (micholes-da-areia), Epinephelus marginatus (garoupa-verdadeira) e Mycteroperca acutirostris (badejo-mira) são quatro espécies simpátricas que pertencem à família Serranidae, de reconhecida importância ecológica e comercial. Este estudo analisou a alimentação destas quatro espécies de peixes no Canal de São Sebastião, Estado de São Paulo (sudeste do Brasil), comparando suas dietas, o uso do habitat e algumas características morfológicas relacionadas ao comportamento alimentar e a distribuição vertical na coluna d'água. Estes quatro serranídeos são predadores oportunistas que utilizam um total de nove táticas diferentes para capturar suas presas, alimentando-se principalmente de crustáceos durante o dia e crepúsculo, e permanecendo estacionários e inativos durante a noite. Um estudo ecomorfológico foi empregado para testar seu valor preditivo. Foi verificado que tal abordagem deve ser utilizada com cautela e sempre complementada com observações diretas no ambiente. Apesar de morfologicamente e comportamentalmente muito semelhantes, D. formosum e D. radiale mostraram divergências com relação ao tipo de substrato preferido pelos maiores indivíduos, que são exclusivamente predadores de espreita. Por outro lado, E. marginatus mostrou possuir hábitos de vida mais sedentários do que M. acutirostris, o mais versátil predador dentre as espécies estudadas. As espécies de Diplectrum estudadas, assim como E. marginatus, podem ser classificadas como serranídeos bentônicos, enquanto que M. acutirostris pode ser classificada como uma espécie nectobentônica.

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