(The methylen-blus reduction-test as prediction of semen quality of rainbow trout, Salmo irideus Gibbons.) / O AZUL DE METILENO DA QUALIDADE DO SÊMEN DA TRUTA ARCO-ÍRIS, Salmo irideus GIBBONS

ABSTRACT

This report details a study about methylene-blue reduction test for semen evaluation for freshwater fishes. Semen was collected from 62 samples of rainbow trout (Salmo irideus GibbonS), of the Estação Experimental de Salmonicultura de Campo do Jordão (São Paulo). The test began with each semen sample diluted at the rate of 1 part semen to 1 part of methylene blue. The methylene-blue reduction time was related with total spermatozoa concentration and with the number of live spermatozoa. The correlation coefficients (r) obtained were -0.36* and -0.40*, respectively, being therefore statistically significant at 5 level of probability. The methylene-blue reduction test can be used as auxiliary method for semen evaluation in the studied species.  

RESUMO

This paper informs on the capture of "manjuba" (Anchoviella lepidentostole) and physical and chemical parameters of the water of Ribeira de Iguape River at 3 locations (Boa Vista, Ponte, Praia do Numa) in Registro (SP). Samples were collected from October 1978 to September 1979. It were detected the locations and times in which occurred the biggest captures; the most significant differences showed among the limnological factors turbidity, electrical conductivity, alkalinity and silica and calcium contents.