Diel feeding pattern and diet of rough scad Trachurus lathami Nichols, 1920 (Carangidae) from the Southwestern Atlantic

Abstract

Diel changes in feeding activity and dietary composition of the rough scad Trachurus lathami were investigated through the analysis of stomach contents of 307 fish sampled over a 24-h period on the continental shelf off Ubatuba (23 o 35´S 45 o W). Stomach contents were analyzed by frequency of occurrence (O%), percent number (N%), percent mass (M%), and feeding index (FI% = O% * M%). Rough scad fed on mollusks (Gastropoda, Crepidula sp.), crustacean (Ostracoda, Copepoda, decapod larvae), chaetognat and teleostean fish. The main items were calanoid copepods (Eucalanus sp. and Centropages sp.). According to the analysis of the stomach fullness and prey digestion, T. lathami is both a diurnal and nocturnal feeder, showing some seasonal variation in feeding time. According to the Chronobiology concept, it was raised the hypothesis of circadian rhythm in feeding of this fish, probably synchronized by light/dark cycle.O estudo da dieta e do padrão diário e sazonal de atividade alimentar do chicharro Trachurus lathami foi realizado através de análises dos conteúdos estomacais de 307 peixes amostrados em estações fixas de coleta de 24 horas na plataforma continental ao largo de Ubatuba (23 o 35´S 45 o W). Os conteúdos estomacais foram analisados através da freqüência numérica (N%), massa porcentual (M%) e freqüência de ocorrência (O%) dos itens alimentares, e índice alimentar (O% * M%). A espécie caracterizouse por ingerir principalmente copépodes calanóides (ex. Eucalanus sp. e Centropages sp.), além de outros crustáceos (Ostracoda, larva de decápodes), moluscos (Gastropoda: Crepidula sp.), quetognatos e peixes teleósteos. De acordo com o grau de repleção estomacal e grau de digestão das presas, T. lathami ingeriu alimento tanto na fase clara quanto na fase escura do dia, apresentando variação sazonal no horário de tomada de alimento. De acordo com os conceitos da Cronobiologia foi levantada a hipótese de ritmo circadiano na atividade alimentar, provavelmente sincronizado pelo ciclo claro/escuro.

Trophic Groups Of Demersal Fish Of Santos Bay And Adjacent Continental Shelf, São Paulo State, Brazil: Temporal And Spatial Comparisons

“…feeders; G7 = piscivores; G8 = ophiuroid and crab feeders; G9 = polychaete feeders; G10 = amphipod and polychaete feeders. See table 1 for fish species codes The diet composition of the species analyzed in the Santos region was consistent with that found for the Southeastern region of Brazil (SOARES, 1989;SOARES et al, 1992;MUTO et al 2001;VAZZOLER, 2001;CORRÊA et al, 2005;CARVALHO;SOARES, 2006;VERA;MARION et al, 2011;SOARES, 2011), though the prey contributions to the diet are different for some species.…”

Trophic model of the outer continental shelf and upper slope demersal community of the southeastern Brazilian Bight

“…Many of the dominant fishes inhabiting such areas are demersal, feeding largely on benthic invertebrates (e.g. Morato et al 1999, Martins et al 2005, Velasco and Castello 2005, Carvalho and Soares 2006, Bautista-Vega et al 2008. The abundance of these fish communities is reflected in their catches.…”

Age structure and growth of the rough scad, Trachurus lathami (Teleostei: Carangidae), in the Southeastern Brazilian Bight

“…Except for the summer of 2008, the typical spring-summer pattern (September to March), when the rough scad schools usually concentrated between 23° and 26°S for spawning, was observed. Such movement coincides with the most productive period in terms of water column eutrophication (Castro et al 2006) and biological productivity (Pires-Vanin et al 1993), which favors the rough scad in terms of their feeding habits (Carvalho and Soares 2006) and conditions for larval growth (Katsuragawa and Matsuura 1992).…”

“…Its life cycle and fishery (Saccardo 1987, Saccardo and Kasturagawa 1995, Saccardo et al 2005; growth (Saccardo and Katsuragawa 1995); diet (Meneghetti andAlves 1971, Carvalho andSoares 2006); parasites (Braicovich et al 2012); and larvae and juveniles (Katsuragawa and Matsuura 1992, Katsuragawa and Ekau 2003, Campos et al 2010) have been investigated. Some biological aspects can be summarized from those studies, as follow.…”