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Baía Norte (North Bay) in Santa Catarina State is considered a typical coastal bay and is surrounded by a network of Marine Protected Areas. The objectives of this study were to describe the composition of the demersal fish assemblage, identify seasonal and spatial structures on a fine scale and evaluate the role of habitat descriptors and abiotic variables affecting the fish assemblage structure. Seasonal samplings were conducted in 2005, using bottom trawls in six pre-established areas in Baía Norte in summer, fall, winter and spring. Simultaneously with each trawl, environmental data were collected with a multiparameter probe. Temporal and spatial differences in fish abundance were tested by a PERMANOVA. To illustratethe differences detected graphically we ran a canonical analysis of principal coordinates (CAP). The influence of environmental variables on the fish fauna was evaluated using a Distant Based Linear Model (DistLM) with Akaike's information criterion (AIC). A total of 9,888 specimens, distributed in 27 families and 62 species, were collected. Citharichthys spilopterus was the most abundant species. PERMANOVA detected differences for abundance between seasons, areas and interaction among all the factors. The DISTLM selected temperature and pH. The results highlight seasonality as an important factor in the structuring of fish fauna of the study place.

ResumoEste estudo teve como objetivo descrever as variações espaço-temporais da ictiofauna em uma laguna costeira aberta. Os peixes foram coletados na Lagoa da Conceição, Florianópolis-SC, totalizando 19 meses de amostragem entre outubro de 1987 e novembro de 1989. Foram realizadas coletas em sete pontos, sendo que em cada um foram empregados lances de tarrafa de diferentes malhas, rede de mão do tipo puçá, rede de arrasto de praia e pesca manual com anzóis. Foram coletados 8.299 indivíduos, classiicados em 61 espécies pertencentes a 28 famílias de peixes, totalizando 52.902,4 g. Em relação à permanência na laguna, 48 espécies (80%) foram classiicadas como visitantes e as outras 12 eram residentes. Foram observadas diferenças signiicativas entre as estações (n, biomassa, riqueza de espécies e H'Loge), entre as áreas (n e riqueza de espécies) e nas interações entre os fatores estação e área (n e biomassa). Os dados sobre a ictiofauna reforçam a importância ecológica do ambiente da laguna costeira como área berçário e de alimentação, já que a maioria das espécies encontra-se em fases de recrutamento dentro da Lagoa da Conceição. Palavras-chave: Ictiofauna; Laguna; Variação espaço-temporal Revista Biotemas, 28 (3), setembro de 2015 94 D. Borgo et al. Abstract Are the ish distribution patterns in an open coastal lagoon in the subtropical west Atlantic inluenced by spatial and seasonal variations?This study aimed to describe the spatial-temporal variations of the ish fauna in an open coastal lagoon. Fish were collected in Lagoa da Conceição, Florianópolis, Santa Catarina, Brazil, totaling 19 sampling months between October 1987 and November 1989. Sampling took place at 7 sites, and in each of them cast net throws of different meshes, "puçá" handheld ishing net, beach seine ishing net, and manual ishing hooks were used. A total of 8,299 individuals were collected, classiied into 61 species belonging to 28 ish families, totaling 52,902.4 g. Regarding stay in the lagoon, 48 species (80%) were classiied as visitors and the other 12 were residents. Signiicant differences were observed between seasons (n, biomass, species richness, and H'Loge), between areas (n and species richness), and in the interactions between the factors season and area (n and biomass). Data on ish fauna reinforce the ecological signiicance of the coastal lagoon environment as a nursery and feeding area, since most species are at recruitment stages within Lagoa da Conceição.

A B S T R A C TInterpreting fish community records is challenging for several reasons, including the lack of past ichthyofauna data, the cyclical temporal variations in the community, and the methodology employed, which usually underestimates fish assemblages. The objective of this study was to describe short-scale and meso-scale (nycthemeral period and months, respectively) temporal variations in the ichthyofauna composition and structure of a sheltered beach of Baía Norte (Florianópolis, Santa Catarina state, Brazil), using a capéchade net. Samples were collected monthly for a period of 48 hours. During the period from December 2010 to November 2011, a total of 19,302 individuals belonging to 89 species and 39 families were captured. The number of individuals that were sampled during the day and/or night was dependent on the sampling month. On average, the daytime assemblage was more abundant and different in structure and composition than the nighttime assemblage. Of the eight species that had the highest Index of Relative Importance (%IRI), five had higher variations (ANOVA F) between the day and night than between the months. This finding reinforced the need for sampling during both the day and night. The capéchade net effectively captured demersal and pelagic individuals in a broad range of sizes. R E S U M OA interpretação dos registros da comunidade ictíica têm se mostrado um desafio por diversos motivos, entre eles a falta de dados pretéritos, existência de variações temporais cíclicas na comunidade e pelos métodos utilizados que geralmente subamostram a assembleia. Neste sentido, o objetivo do presente trabalho foi descrever o padrão de variação temporal (nictemeral e mensal) na composição e na estrutura da ictiofauna de uma praia abrigada da Baía Norte de Florianópolis, usando uma rede capéchade. Coletas foram realizadas mensalmente, integrando um período de 48 horas/mês. Durante os meses de dezembro de 2010 a novembro de 2011, 19302 indivíduos distribuídos em 89 espécies e 39 famílias foram capturados. O número de indivíduos capturados durante o dia e/ou noite foi dependente do mês de coleta. Em média, a assembleia foi mais abundante durante o dia, diferindo em estrutura e composição do período da noite. Das oito espécies com maior Índice de Importância Relativa (IRI%), cinco apresentaram maior variação (F ANOVA) entre o dia e a noite do que a verificada entre os meses, o que reforça a necessidade de amostragens durante o dia e a noite. A rede capéchade foi eficiente na captura de indivíduos demersais e pelágicos com ampla faixa de tamanho.

ABSTRACT. We use two taxonomic indexes to assess the variability of the taxonomic structure and diversity of the ichthyofauna of two low-energy environments in southern Brazil and to compare the temporal patterns of these two ichthyofaunas. Sampling was conducted in the infralittoral zones of Maciel (Paranaguá Bay, PR) and Indio Beach (Norte Bay of Florianópolis, SC). A fyke net was set up at a depth of 0.5 to 2.0 m and left in place for 48 h for each of the samplings. A total of two diurnal and two nocturnal samplings were conducted monthly per one year. The ichthyofaunas at the two sites exhibited similar temporal dynamics, with their abundance and biomass presenting a tendency to increase with increasing temperature during the spring and summer months. A total of 113 species were captured, of which 47 were present at both sites. Harengula clupeola, Sphoeroides testudineus and S. greeleyi were especially abundant at both sites. The co-occurring species displayed similar day and night occupancy trends. In all seasons, the obtained values for the average taxonomic distinctness and variation in taxonomic distinctness were within the confidence intervals. The seasonal reproduction and recruitment patterns led to slight changes in taxonomic distinctness during the year, which were within the expected intervals. Keywords: ichthyofauna, taxonomic distinctness, nycthemeral dynamics, sheltered beach, southern Brazil.Comparación de los patrones taxonómicos y temporales de la ictiofauna capturada con red fyke en dos ambientes protegidos en el sur de Brasil RESUMEN. Se utilizaron dos índices taxonómicos para evaluar la variabilidad de la estructura taxonómica y diversidad de la ictiofauna en dos ambientes de baja energía en el sur de Brasil, así como para comparar sus patrones temporales. Los muestreos se realizaron en las zonas infralitoral de Maciel (Bahía de Paranaguá, PR) e Indio Beach (Bahía Norte, SC). Se instaló una "fyke net" a una profundidad de 0,5 a 2 m, durante 48 h, para cada uno de los muestreos. Durante un año se realizó un total de dos muestreos diurnos y dos nocturnos. La ictiofauna en los dos sitios mostró dinámicas temporales similares, con su abundancia y biomasa presentando una tendencia a aumentar con el incremento de la temperatura durante los meses de primavera y verano. Un total de 113 especies fueron capturadas, de los cuales 47 estuvieron presentes en ambos sitios. Harengula clupeola, Sphoeroides testudineus y S. greeleyi fueron especialmente abundantes en ambos sitios. Las especies coexistentes mostraron tendencias similares de ocupación tanto de día como de noche. En todas las estaciones, los valores obtenidos para la distinción taxonómica media y para la variación en la distinción taxonómica estuvieron dentro de los intervalos de confianza. Los patrones de reproducción y reclutamiento estacionales llevaron a ligeros cambios en la distinción taxonómica durante el año, que estuvieron dentro de los intervalos esperados. Palabras clave: ictiofauna, distinción taxonómica, dinámica nictimeral, play...

ABSTRACT. The relative efficiency of two square-mesh codend designs with the same circumference (~2 m) but different mesh sizes and materials (32 mm polyethylene-PE and 30 mm polyamide-PA) was tested in an artisanal shrimp trawl fishery in Paraná, southern Brazil. The two square-mesh codends were hauled alternately with a 26 mm diamond-shaped mesh codend (control) in a twin gear configuration. Although not significant, the mean numbers of total bycatch were reduced by 16.6 and 10.0% with the 32 and 30 mm square-mesh codends, respectively. The results indicate significant improvement in size selectivity for some species (Xiphopenaeus kroyeri and Stellifer rastrifer). The operational changes tested can be a suitable technical solution for reducing the capture of immature organisms in the shrimp trawl fishery in Paraná, Brazil.