Trophic resource partitioning of two snook fish species (Centropomidae) in tropical estuaries in Brazil as evidenced by stable isotope analysis. (15th October 2019)

• Record Type: Journal Article
• Authors: Gonzalez, Júlio Guazzelli; Ménard, Frédéric; Le Loc'h, François; Andrade, Humber Agrelli de; Viana, Andréa Pontes; Ferreira, Valdimere; Lucena Frédou, Flávia; Lira, Alex Souza; Munaron, Jean-Marie; Frédou, Thierry
• Is Part Of: Estuarine, coastal and shelf science. Volume 226(2019)
• Publication Date: 2019-10-15
• Subjects: Brackish water fish -- Trophic relationships -- Carbon -- Nitrogen -- Centropomus; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2019.106287
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: We investigated the trophic niches and the resource partitioning of two snook species, the common ( Centropomus undecimalis ) and the fat snook ( C. parallelus ), in four tropical estuaries of the northeastern Brazil, using stable isotope analyses of carbon (δ 13 C) and nitrogen (δ 15 N). Fish specimens, mainly juveniles, basal resources and a primary consumer were collected in 2015 during dry and rainy seasons in all estuaries, which exhibited differences in system size, geomorphologic shapes, levels of sea access and anthropic pressures. Potential effect of factors like fish body length, estuary and seasonality on isotope ratios were investigated. Positive relationships between the size of fish and δ 15 N values were found, regardless the species. Our results indicated that snooks can be characterized as secondary consumers and have close trophic niches in most estuaries. Trophic overlaps were more pronounced within the largest estuaries (Catuama and Santa Cruz), whereas smaller systems that have restricted connections to the sea presented low isotopic niche overlap between both species (Suape and Sirinhaém). Moreover, a higher variability of δ 13 C and δ 15 N values in snooks was found in larger estuaries undergoing stronger influences from coastal adjacent waters. Although we were not able to detect clear seasonal effects, greater isotopic overlaps were found during the rainy season. Despite the lack of intrinsic differences in life history traits, both species, dominated by juveniles, shared similar trophic niches in these environments. Highlights: δ 13 C and δ 15 N of two Centropomidae were investigated in four estuaries in Brazil. Juveniles of Centropomus undecimalis and C. parallelus have close isotopic niches. Trophic overlaps were more pronounced in large estuaries. Resource partitioning process might reflects the resource availability in estuaries.