Environmental influences on the spatial and temporal distribution of the puffer fish Sphoeroides greeleyi and Sphoeroides testudineus in a Brazilian subtropical estuary

Abstract

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.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.

Feeding and spatial distribution of two estuarine puffer fish in a tropical estuary, north-eastern Brazil

“…The higher abundances of juvenile S. testudineus were recorded in the upper estuary (Tidal Creek 3) suggesting the recruitment period was during the dry season, and this period was reported in a subtropical area during the summer period (Fávaro et al ., 2009), coinciding with higher salinity and temperature. However, the adults were recorded in the lower estuary (Mudflat and Creek 1) during the rainy season, when the biomass of the fishes was already higher.…”

“…Giarrizzo et al (2010) suggested this species displayed tidal migratory behaviour in tropical estuaries during ebb tide, and such behaviour may have influenced our results, because all sampling was carried out at low tide. Furthermore, biotic interactions may have played important implications for distributions of species, since closely related estuarine species often exhibit differences in size or behaviour that may reduce competition and allow coexistence (Fávaro et al ., 2009).…”

Spatiotemporal variation among demersal ichthyofauna in a subtropical estuary bordering World Heritage-listed and marine protected areas: implications for resource management

“…Potentially, these species may be more adapted to the consistent conditions observed in the north-south axis, or greater availability of suitable habitat (shallow water with adjacent mangroves). Other studies have demonstrated a preference by tetraodontids for such areas (Rocha et al 2002;Schultz et al 2002;Fávaro et al 2009;Pichler et al 2015).…”

Variação temporal de peixes em diferentes fases ontogenéticas em uma praia abrigada da Baía Norte, Sul do Brasil

“…Diferentemente, S. greeleyi foi pouco abundante no estágio 1, com maiores capturas deste estágio no outono. Juvenis de S. testudineus foram também abundantes em áreas rasas da Baía de Paranaguá, com predominância de juvenis sobre adultos durante quase todo ano, e com juvenis de S. greeleyi em maior núme-ro no verão e no outono (Fávaro et al, 2009). Entretanto, o método amostral utilizado por Fávaro et al (2009) pode ter subamostrado os adultos, que possuem maior capacidade de fuga da rede de arrasto utilizada (Halliday e Young, 1996;Suda et al, 2002).…”