Biologia reprodutiva e hábitos alimentares do rodóstomo (Hemigrammus bleheri) um peixe ornamental da Bacia do Médio Rio Negro, Estado do Amazonas, Brasil.

Abstract

Esse estudo teve como objetivo descrever a biologia reprodutiva e os hábitos alimentares de Hemigrammus bleheri do médio Rio Negro, estado do Amazonas-Brasil, ao longo de um ciclo hidrológico. Para tanto, analisou-se os estádios de maturação gonadal, tamanho de primeira maturação sexual (L50), fecundidade e período reprodutivo de 260 indivíduos, além da análise do conteúdo estomacal e cálculo do índice de repleção estomacal de 177 indivíduos. Os resultados obtidos demonstram que a espécie possui desova parcelada, com oócitos variando entre 0,06 a 0,66 mm de diâmetro, e fecundidade entre 101-721 oócitos. O L50 foi estimado em 2,8 cm para fêmeas e 2,6 cm para machos. As fêmeas amadurecem com a subida do rio (Dezembro a Maio) e às desovas ocorrem em maior proporção no final da enchente (Março a Maio). A espécie é onívora, consumindo grande parte dos alimentos de origem autóctone. A dieta básica mostrou variações sazonais em sua composição, pois, observou-se que microcrustáceos são frequentes nos períodos de enchente/cheia, e algas filamentosas, quironomídeos e fragmentos vegetais são mais frequentes na vazante/seca. Alterações sazonais na atividade alimentar foram registradas provavelmente influenciadas pelo pulso de inundação. O grau de repleção estomacal foi maior na enchente/cheia e menores na vazante/seca. Palavras-Chave: rodóstomo; alimentação; reprodução; ambiente natural; rio Negro; Bacia Amazônica. REPRODUCTIVE BIOLOGY AND FEEDING HABITS OF Hemigrammus bleheri (CHARACIFORMES: CHARACIDAE) AN ORNAMENTAL FISH THE MIDDLE NEGRO RIVER BASIN, AMAZONAS STATE, BRAZIL ABSTRACTThe aim of this study is to describe the reproductive biology, diet and the feeding activity of Hemigrammus bleheri from middle Rio Negro, State of Amazonas-Brazil, along the a hydrological cycle. For this, the gonadal maturation stage, size of first sexual maturation (L50), fecundity and reproductive period of 260 individuals were analyzed, as well, the stomach contents of 177 individuals were analyzed and their stomach fullness index was calculated. The results indicate that this species has multiple spawning, with oocytes varying between 0.06 and 0.66 mm in diameter, and fecundity between 101-721 oocytes. The first sexual maturation size (L50) was estimated at 2.8 cm for females and 2.6 cm for males. Females mature with the flood pulse (December to May) and spawning occur in greater proportion at the end of the flood (March to May). The species is omnivorous, consuming a large part of the food of autochthonous origin. The basic diet showed seasonal variations in its composition, because it was observed that microcrustaceans have their increased importance in flooding/flood periods, and filamentous algae, chironomids and vegetal fragments are more frequent in the drying/dry season. In addition, seasonal changes in food activity were also recorded, probably influenced by the flood pulse, as the degree of stomach repletion was higher in flooding/flood and lower in drying/dry.

Ichthyological ethnoknowledge of the “piabeiros” from the Amazon region, Brazil

“…), acará disco ( S. discus ), and ethnocategories araias (Potamotrygonidae) and bodó (Loricariidae). Rodostomo ranks second on the list of the species most exported from the state, second only to the cardinal, and corresponds to about 6% of the total volume of fish exported (20 to 30 million fish exported annually from the state of Amazonas) [ 25 ].…”

“…According to fishers, the diet of ornamental fish species is quite diverse; however, periphyton was identified as the main food item of most species. It was observed that the ornamental fish species from the middle Negro River basin that were cited by fishers tend to inhabit igarapés and igapó forests at different times and occupy these environments in search of food [ 25 , 30 ]. According to [ 35 ], the food base for some of the fish in the igarapé is composed of small terrestrial invertebrates (ants and termites) when they fall into the water, as well as the mosquito larvae (Diptera) present at the bottom of these environments.…”

“…As well as their feeding behavior, in the fishers’ view, the reproductive cycle of ornamental fish species is also influenced by annual variations in water levels in the region’s rivers, with the period of rising river levels being the main breeding season for the species. In the Amazon region, several species of ornamental fish demonstrate synchronism of the reproductive cycle with the initial phase of increasing water levels [ 25 , 30 , 31 ].…”