Ecomorphology and resource use by dominant species of tropical estuarine juvenile fishes

Abstract

Eleven ecomorphological attributes and diet of seventeen juvenile fish species were examined to test the hypothesis that morphological patterns determine resource uses in estuarine habitats. Species were separated according to the apparatus to food capture and habitat use (benthic or pelagic) in three different groups: (1) a group with depressed fish body, strong caudal peduncle and enlarged pectoral fins; (2) a second group laterally flattened with a wide protruding mouth, and (3) a third group strongly flattened with small pectorals fins. The following six trophic groups were organized based on prey categories: Zooplanktivores, Benthivores, Omnivores, Detritivores, Macrocarnivores and Insectivores. Significant results (PERMANOVA) between ecomorphological indices and habitat and between ecomorphological indices and trophic groups were found. These data indicate that similarity of ecomorphological forms, which minimize the influence of environment and partitioning of food, would help facilitate the co-existence of these fish when they are abundant in this tropical estuary.Onze atributos ecomorfológicos e a dieta de dezessete espécies de peixes juvenis foram examinados para testar a hipótese de que os padrões morfológicos determinam a utilização dos recursos em habitats estuarinos. As espécies foram separadas de acordo com o modo de captura do alimento e uso do habitat (bentônicos ou pelágicos) em três grupos distintos: (1) um grupo de peixes depressiformes, com forte pedúnculo caudal e nadadeiras peitorais alargadas; (2) um segundo grupo, compressiforme, com ampla boca protrusível, e (3) um terceiro grupo, fortemente achatado e com pequenas nadadeiras peitorais. Seis grupos tróficos foram organizados com base nas categorias de presas: Zooplanctívoros, Bentívoros, Omnívoros, Detritívoros, Macrocarnívoros e Insetívoros. Foram encontrados resultados significativos (PERMANOVA) entre os índices ecomorfológicos e o habitat e entre os índices ecomorfológicos e os grupos tróficos. Estes dados indicam que a similaridade ecomorfológica, que reflete o ambiente e o tipo de alimento consumido, facilitaria a coexistência desses peixes quando estes são abundantes neste estuário tropical.

Exploring ecosystem functioning in two Brazilian estuaries integrating fish diversity, species traits and food webs

“…List of the 9 traits tested in the study, with morphological traits measured on captured fish. Formula adapted from Villéger et al (2012) and Pessanha et al (2015). Bh -body height; Bw -body width; Bl -body total length, Hh -head height along the vertical axis of the eye, Mh -mouth height; Mw -mouth width; Eh -eye height; PFl -pectoral fin length; PFw -pectoral fin width; CPl -caudal peduncle length; CPhcaudal peduncle height; CPw -caudal peduncle width; CPh -caudal fin height.…”

Differences in trophic resources and niches of two juvenile predatory species in three Pangani estuarine zones, Tanzania: stomach contents and stable isotope approaches

“…Such justifications are supported by the long-term, isotopic signal dietary tracers that reveal diets consumed by the species for the past 3 months. More so, the high occurrence of large sized preys like brachyura in the diet of E. malabaricus in contrast to numerous juvenile shrimps predated by C. chrysophrys could be correlated to differences in their mouth morphology [ 30 , 53 ].…”

Intraspecific food resource partitioning in Brazilian silverside Atherinella brasiliensis (Atheriniformes: Atherinopsidae) in a tropical estuary, Brazil

“…A numeric vernier calliper (0.1 mm precision) was used to measure: total length (TL), standard length (SL), body height (BH), mean body height (MHB), body width (BW), head length (HL), head height (HH), relative eye height (ERH), pectoral fin length (PFL), pectoral fin width (PFW), caudal fin height (CFH), caudal peduncle length (CPL), caudal peduncle height (CPH), caudal peduncle width (CPW), mouth width (WM) and mouth height (HM). Morphological measurements were transformed following the method of Schaefer (1992) and Pessanha et al (2015). Such transformations allow the removal of the body size effect, which standardises the measures, taking into account the effect of standard length on the analyzed morphological attributes.…”