Reprodução e alimentação de algumas espécies de peixes da lagoa rodrigo de freitas, Rio de Janeiro

Abstract

The article aims at studying reproduction aspects of Poecilia vivipara; Jenynsia multidentat; Phalloptychus januarius; ichthyoplankton composition and spatial distribution; feeding aspects of Jenynsia multidentata and Geophagus brasiliensis; considered benthopelagic species. Reproductive aspects of Poecilia vivipara population embryos showed four developmental stages until birth with sexual differentiation occurring after 15mm. Jenynsia multidentata reproduces throughout the whole year, with its first maturation occurring at 32mm. Embryos showed four developmental stages until birth, with sexual differentiation occurring after 13mm. Some aspects of Phalloptychus januarius reproduction, such as male and female proportion, female first pregnancy size, different stages of embryologic development and reproductive activity, were studied. First maturation was observed since 19mm total length. The embryos showed four different embryonic stages until the age of birth. The male's sexual dimorphism could be observed from 15mm total length. Jenynsia multidentata, with its first maturation occurring at 32mm. Embryos showed four developmental stages until birth, with sexual differentiation occurring after 13 \mm; ichthyoplankton were represented by families Atherinopsidae, Blenniidae, Clupeidae, Engraulidae, Gerreidae, Gobiidae, Mugilidae, Sciaenidae and Achiridae. Benthic fish diet, the principal feed components were represented by 60, 14% of organic matter, 26.04% of Navicula, 3,38% of Cladophora, 1.72% of Polychaeta, 1.16% of eggs, 1.04% of Pleurosigma, 0,83% of Chroococcus, 0.77% of Enteromorpha, 0,74% of Amphora, besides Ectocarpus, insect and microcrustacean fragments, Terpsinoe, Psychodidae, fry, Coscinodiscus, Cocconeis, barnacles, nauplius, Gomphonema, Isopoda, Amphipoda, Chilopoda and Ephidridae, reaching a total of 3,47%; The main stomachal items found in benthonic fishes were: particulate organic matter, eggs, polychaetae, algae and quartz crystals. The highest percentage of organic matter was founded in the Microbius meeki, Prinotus punctatus, Dormitator maculatus and Genidens genidens stomachs. In the Dormitator maculatus, Gobionellus oceanicus and Achirus lineatus stomachs were observed the highest percentages of polychaetae, while in A. lineatus and in A. tajasica stomachs were found a high percentage of quartz crystals probably eaten with epibenthic material.