Diel variation in fish assemblages in tidal creeks in southern Brazil

Abstract

Tidal creeks are strongly influenced by tides and are therefore exposed to large differences in salinity and depth daily. Here we compare fish assemblages in tidal creeks between day and night in two tidal creeks in southern Brazil. Monthly day and night, simultaneous collections were carried out in both creeks using fyke nets. Clupeiformes tended to be caught more during the day. Cathorops spixii, Genidens genidens and Rypticus randalli tended to be caught at night. Sciaenidae also tended to be caught more during the night. In general, pelagic species were diurnal, while deep water species were nocturnal. These trends are probably due to a variety of causes, such as phylogeny, predation and net avoidance.Keywords: tidal creeks, fish, diel variation. Variação diuturna nas assembléias de peixes dos rios de maré do sul do Brasil ResumoAs gamboas são canais com traçado meandrante altamente influenciados pelas marés e sofrem grande variação de salinidade e profundidade em um mesmo dia. O objetivo deste trabalho foi comparar as assembléias de peixes diurna e noturna, e para tanto foram escolhidas duas gamboas no sul do Brasil. Coletas mensais foram feitas simultaneamente na maré vazante da tarde e na maré enchente da noite, com o auxílio de redes fyke. Os clupeiformes exibiram tendência para captura diurna. As espécies: Cathorops spixii, Genidens genidens e Rypticus randalli exibiram forte tendência para captura noturna. A família Sciaenidae também mostrou tendência para captura noturna. De forma geral, espécies pelágicas foram mais capturadas durante o dia, e espécies mais relacionadas ao fundo foram mais capturadas à noite, e isto se deve à ação conjunta de vários fatores, tais como: padrões filogenéticos, fuga do instrumento de coleta e busca de locais mais protegidos contra predação.Palavras-chave: gamboas, peixes, variação diuturna.

Analysis of fish assemblages in sectors along a salinity gradient based on species, families and functional groups

“…Juveniles of D. rhombeus prefer shallow mesohaline areas, such as beaches and mangrove channels, to grow and store somatic reserves during the reproductive period (MENEZES; FIGUEIREDO, 1980;OTTO, 1998). H. clupeola (zooplanktivorous marine straggler) and A. tricolor (zooplanktivorous estuarine species) were more abundant in the euhaline sectora finding was not in accord with observations from other estuaries (FALCÃO et al, 2006;FÉLIX et al, 2006;OLIVEIRA-NETO et al, 2008;CONTENTE et al, 2011a). Differences in sector usage by A. januaria, D. rhombeus and H. clupeola most likely occur due to differences in the salinity tolerances of these species.…”

“…In fact, each family may contain many species, each with a different capacity for reaching their optima in different salinity zones (ELLIOTT et al, 2007, BLABER, 2008. For example, E. melanopterus and E. argenteus were two of the most important species in the PEC mesohaline and polyhaline zones, respectively VENDEL et al, 2002VENDEL et al, , 2003SPACH et al, 2006;FALCÃO et al, 2006;FÉLIX et al, 2006;OLIVEIRA-NETO et al, 2008, CONTENTE et al, 2011a.…”

Estuarine ichthyofauna of the Paraguaçu River, Todos os Santos Bay, Bahia, Brazil

“…There is a significant contribution of marine species in the inner estuary, most notably in mangrove creeks (Castro 2001) during a certain stage of the life cycle where the juveniles use these environments (Barletta et al 2003, Oliveira-Neto et al 2008). However, was observed an advancement of marine species, especially the adults (marine stragglers, marine migrants) for inner regions toward the middle estuary, showing greatest abundance and constancy of occurrence in this sector (e.g.…”

Diel Variations and Ecological Aspects in Fish Assemblages of a Sandy Beach in the Semi-Arid Region of Northeast Brazil.

“…However, due to the low abundance and frequency of occurrence in the samples, it is not possible to state that these species occur mainly in the night period. The most numerous species during the day (Chirocentrodon bleekerianus and Pellona harroweri) usually form shoals, which are generally larger and more common during the day (Helfman, 1993;Oliveira-Neto et al, 2008). In shoals, these species are more protected from visual predators such as fish and seabirds (Félix-Hackradt et al, 2010).…”

“…In this context, the hypothesis that the fish assemblage is differentially structured between day and night period was tested. In Brazil, some studies have been performed focusing on fish assemblages and nictemeral variations Pessanha & Araújo, 2003;Barreiros et al 2005;Gaelzer & Zalmon, 2008;Oliveira-Neto et al, 2008;Félix-Hackradt et al 2010;Vasconcelos et al 2010;Ribeiro et al 2014). It is important to note that all publications refer to the South and Southeast regions.…”