Resumo A variabilidade da estrutura de assembleia de peixes em relação à sazonalidade da salinidade e produtividade ainda não foi elucidada para muitos estuários Neotropicais. Neste estudo, testamos a hipótese de que um conjunto de variáveis relacionadas à produtividade e ao gradiente de salinidade estuarino determina a estrutura da ictiofauna de habitats rasos do eixo norte-sul do Complexo Estuarino de Paranaguá (litoral sul brasileiro). As amostras foram obtidas mensalmente com “picaré”, entre maio de 2000 e abril de 2001. Corroborando com a hipótese, riqueza e abundância aumentaram em águas mais turvas e quentes nas estações chuvosas e produtivas de verão, favorecendo reprodução, bem como recrutamento e crescimento juvenil que são mais intensos neste período. Abundância foi maior nas zonas internas, devido à maior oferta de alimento e habitat. Riqueza foi maior em águas mais salinas, devido à proximidade da ictiofauna marinha, que é mais rica. Sugerimos que intervenções humanas locais (como dragagem) sejam evitadas nas estações chuvosas que são críticas para o ciclo de vida das espécies. Salinização, redução da produtividade estuarina e águas mais quentes, esperadas com a mudança climática global e impactos humanos na bacia hidrográfica local, poderão afetar a integridade da ictiofauna local.

Abstract The variability of fish assemblage structure with respect to seasonality in salinity and productivity remains to be elucidate to many Neotropical estuaries. In this study, we hypothesized that salinity gradient and a set of variables related to ecosystem productivity drive community parameters in the shallow-water fish assemblage of the north-south axis of the Paranaguá Estuarine Complex (Southern Brazilian coast). Samples were taken with beach seine monthly from May 2000 to April 2001. Supporting our hypothesis, richness and abundance increased with turbidity, warmer waters of the rainier summer seasons, which are more productive. This environmental setting favors reproduction, as well as juvenile recruitment and growth, whose intensities are highest in this period. Highest abundance was found in inner areas, which may be explained by greater food and habitat availability. Richness was higher in more saline waters, due to the proximity of the rich pool of marine fish species. We suggest that local human interventions (e.g., dredging) should be avoided during the rainy seasons that are critical for species life cycles. Salinization, low estuarine productivity, and warmer waters, which are expected with climate change and human impacts in the local watershed, could affect the integrity of the local fish assemblage.

ABSTRACT Menticirrhus americanus were sampled (n = 393) from two beaches (P1 is an estuarine beach near the mouth of the Paranaguá Estuarine Complex, and P2 is a beach adjacent to the Paranaguá Estuarine Complex) in the subtropical region of the western South Atlantic waters between August 2015 and June 2016. This study aimed to identify the spawning season and the age structure for M. americanus using two sampling methods. For sampling at the P1 beach, seine, line, and pole were used, while samples from the P2 beach were obtained from the artisanal fishers. Females were numerically dominant in all sampling months at both sites except for February when the males became dominant. The species exhibited a protected reproductive season with multiple spawning peaks between August and December. Males and females were captured at all gonadal development stages and ages between 1 and 6 from both sites. At first maturity, the length of the females was 16.3 cm, and the mean age at first maturity was 1.3 years. Individuals aged between 1 and 3 years were dominant (68%). The results suggested that young and adults of the M. americanus use the same habitats throughout their ontogeny.

Abstract This study aimed to verify variations in the form of the sagitta otolith of Menticirrhus americanus as to their ontogeny, sex and stage of such structure. Ontogenetically were found significant differences (p < 0.05) for all shape indices (aspect ratios, shape factor, rectangularity, ellipticity, relative surface of sulcus acusticus) and also in the wavelet of the otolith. The CVA presented a 98.6% correct reclassification of the otolith between interval class. Sexual variations were found in the wavelet and in the relative surface of sulcus acusticus index. Between adult females and young females, differences were not detected in the wavelet and rectangularity, but significant differences were found in all other shape indices. The CVA presented a 79.6% correct reclassification of the otolith of the sexes and stages of life sampled. Young females and adults females showed highest correct percentage of classification. The results of this study demonstrate for the first time the influence of the ontogenetic variation and sexual in the form of the otoliths.

RESUMO Estudos de idade e crescimento são fundamentais para o sucesso da gestão pesqueira. Zapteryx brevirostris (Müller & Henle, 1841) distribui-se pela plataforma continental brasileira, sendo classificada como “Vulnerável” no livro vermelho da IUCN (International Union for the Conservation of Nature). Assim, o objetivo deste estudo foi apresentar informações previamente desconhecidas sobre a idade e o crescimento de Z. brevirostris que podem ser utilizados para sua gestão, conservação e pescas. No total foram amostrados 162 espécimes, com comprimento total (CT) variando de 35.7 cm a 56 cm. As vértebras foram incluídas em resina e seccionadas num corte com cerca de 0.5 mm de espessura, e as bandas de crescimento das vértebras foram lidas com microscópio de luz transmitida branca. Na área estudada, Z. brevirostris possui idades estimadas entre os 4 a 10 anos de idade, de acordo com seu padrão de vértebras. A espécie atinge seu Linf (comprimento máximo assintótico) em torno dos 56 cm (56 cm para fêmeas e 50.37 cm para machos). Essa é a primeira estimativa dos parâmetros de idade e crescimento para uma espécie do gênero Zapteryx, e os resultados obtidos corroboram a hipótese de que a espécie requer uma gestão de conservação adequada, devido sobretudo à sua lenta taxa de crescimento e consequente suscetibilidade à sobre-exploração.

ABSTRACT Age and growth studies are fundamental to successful fisheries management. Zapteryx brevirostris (Müller & Henle, 1841) is distributed off the Brazilian continental shelf and this species is assessed as “Vulnerable” in the Red List of the International Union for the Conservation of Nature (IUCN). Thus, the objective of this study was to present previously unknown information about the age and growth of Z. brevirostris that can be used for its management, conservation, and fisheries. A total of 162 specimens were sampled, with total lengths (TL) varying between 35.7 cm and 56 cm. The vertebrae were embedded in resin, sectioned in cuts with 0.5 mm thickness and the growth bands of the vertebrae were read under a light microscope. In the studied area, Z. brevirostris ages were estimated from 4 to 10 years according to vertebrae patterns. The species reaches its maximum asymptotic size (Linf) around 56 cm (56 cm for females and 50.37 cm for males). This is the first estimate of age and growth for a species of the Zapteryx genus, and the results support the hypothesis that this ray requires future management conservation, particularly due to its slow growth rate and consequent susceptibility to overexploitation.

Resumo Este é o primeiro relato de anomalias morfológicas em embriões de Zapteryx brevirostris, espécie comum no Brasil. As brânquias estiveram ausentes, e as nadadeiras peitorais mostraram-se assimétricas e não totalmente formadas e fundidas à cabeça. A nadadeira esquerda, a maior, se projetou destacadamente em direção à cabeça, quase alcançando a altura dos olhos. A nadadeira pélvica esteve ausente, não foi possível a determinação do sexo do animal. A causa da deformidade morfológica é incerta, mas sugere-se que possa estar relacionada a problema nutricional durante o desenvolvimento do embrião.

Abstract This is the first report of morphological anomaly in embryos of Zapteryx brevirostris (Lesser guitarfish), a very common species in Brazil. The gills were absent, and the pectoral fins were not fully formed nor were they completely fused to the head. They were asymmetrical, with the larger left pectoral fin projecting more toward the head (almost at the height of the eyes). The pelvic fin was absent, making sexing impossible. The cause of the morphological deformity is uncertain, although a nutritional problem of the embryo is evoked.

The present study characterizes the oogenesis and the ovarian maturation scale, and determines the reproductive period, type of spawning, recruitment period, and population variations in the reproductive process of the flatfish Achirus lineatus (Linnaeus, 1758). Specimens were sampled on a monthly basis in the shallow near shore area of the Paranaguá Bay, state of Paraná, Brazil, from March 2006 to February 2007. The specimens collected were measured for morphometric data (total length and total weight) and their gonads were exposed for macroscopic evaluation. The gonads were subsequently removed, weighed and processed for microscopic analyses. Six phases of the ovarian follicle development were defined, as well as five ovarian development stages. Growth patterns differed between the sexes: negative allometry for females and positive allometry for males. Based on the seasonal assessments of the distribution of individual GSI values, the distribution of stages of gonadal development, individual body size, sex ratio, the ratio of juveniles to adults, and histological examination of the ovaries, reproduction was found to occur in the spring (spawning in batches), and recruitment in the autumn. These results show that A. lineatus is an estuarine-resident species that uses the study area for reproduction and recruitment, providing an argument in favor of the need to conserve the estuarine environment in order to preserve stocks.

A espécie Astyanax aff. fasciatus foi investigada quanto a diferenças nas táticas reprodutivas em três reservatórios de diferentes idades (Iraí, Piraquara e Passaúna), localizados em uma mesma região geográfica. O material biológico foi obtido através de coletas mensais realizadas de julho/2006 a junho/2007. Evidenciou-se maior atividade reprodutiva nos períodos mais quentes do ano. O valor médio do IGS no reservatório do Passaúna apresentou-se significativamente maior em relação aos valores obtidos nos outros reservatórios. A desova foi caracterizada do tipo total no reservatório do Iraí e do tipo parcelada nos outros reservatórios. A espécie apresentou crescimento alométrico negativo no reservatório do Iraí e alométrico positivo nos reservatórios do Passaúna e Piraquara. O maior valor do fator de condição foi estimado no reservatório do Iraí, seguido pelos reservatórios do Piraquara e Passaúna, respectivamente. Durante o período de estudo as fêmeas predominaram sobre os machos em todos os reservatórios. A análise da proporção sexual por classe de comprimento evidenciou, para os três reservatórios, o predomínio de machos nas menores classes de comprimento. Através destes resultados constatou-se que a espécie utiliza táticas reprodutivas distintas para os reservatórios analisados e que estas táticas parecem refletir o grau de estabilização de cada ambiente.

The species Astyanax aff. fasciatus was investigated as regards differences in reproductive tactics in three reservoirs with different ages (Iraí, Piraquara and Passaúna) located in the same geographic region. The biological material was obtained through monthly collections carried out from july/2006 to june/2007. The average value of the gonadosomatic index (GSI) in Passaúna reservoir was significantly higher in relation to the values obtained in the other reservoirs. Spawning was total in Iraí reservoir and partial in the others. Allometric growth of the species was negative in Iraí reservoir and positive in the others. The highest condition factor value was estimated in Iraí reservoir, followed by Piraquara and Passaúna reservoirs, respectively. Females predominated in all of the reservoirs during the study period. The sex ratio per length class showed, for the three reservoirs, the predominance of males in the smaller length classes. These results verified that the species uses distinct reproductive tactics in the analyzed reservoirs and that these tactics seem to reflect the degree of stabilization of each environment.

A distribuição espacial e temporal de Sphoeroides greeleyi e Sphoeroides testudineus foram estabelecidas a partir de coletas (material biológico e dados ambientais) realizadas mensalmente de maio/2000 a abril/2001 em áreas intertidais, no eixo norte-sul, do complexo estuarino de Paranaguá, Estado do Paraná. A variação dos fatores abióticos coletados, além de caracterizar um gradiente espacial, no sentido norte-sul, que varia sazonalmente, possibilitou a divisão do estuário em três regiões: norte, central e sul. Espacialmente, verificou-se para ambas as espécies que o número de indivíduos decresce, significativamente, no sentido norte-sul estuarino. Ainda, foram encontradas diferenças significativas no porte dos indivíduos entre as regiões do estuário, no norte ocorreram os maiores indivíduos de S. greeleyi e os menores de S. testudineus. As maiores capturas dos baiacus ocorreram do final da primavera ao início do outono, coincidindo com a ocorrência de exemplares de menor tamanho e de menor massa corporal média. Os resultados indicam que as variações espaciais e temporais do ambiente afetam os padrões de distribuição de ambas as espécies de baiacus, sugerindo que a co-ocorrência de espécies aparentadas age como um fator modulador nesta distribuição.

The spatial and temporal distribution of Sphoeroides greeleyi and Sphoeroides testudineus were established from collections (biological material and environmental data) conducted on a monthly basis from May 2000 to April 2001 in intertidal areas along the north-south axis of the estuarine complex of Paranaguá, Paraná State. In addition to characterizing a north-south spatial gradient, which fluctuates seasonally, the variation in the abiotic factors made possible the division of the estuary into three regions: north, central and south. Spatially, it was found that the number of individuals declines significantly for both species in the north-south direction of the estuary. Moreover, significant differences were found in the size of individuals across the estuarine regions. The largest S. greeleyi individuals were caught in the north, as well as the smallest S. testudineus individuals. The catches with the highest numbers of puffer fish occurred from late spring to early autumn, coinciding with the occurrence of specimens of smaller size and lower mean body mass. The results indicate that spatial and temporal variations in the environment impact the distribution patterns of both puffer fish species, suggesting that the co-occurrence of closely related species functions as a modulating factor in that distribution.