Milt quality and spermatozoa morphology of captive Brycon siebenthalae (Eigenmann) broodstock

In order to develop artificial reproduction in freshwater fish for potential species to be developed in South American aquaculture, milt quality and sperm morphology were studied in yamu (Brycon siebenthalae) under captive conditions during the natural middle spermiation period. The volume of milt collected for each male was 1.8 +/- 1.2 mL and the sperm concentration was 13.9 +/- 4.0 x 10(9) spermatozoa mL(-1). Spermatocrit (41.5 +/- 10.8%) was positively associated (r(2)=0.30) with sperm density calculated using a corpuscle counting chamber. Sperm motility was 88 +/- 9% and the average duration of forward motility was 41 +/- 7 s. Fertilization rate was 84 +/- 8% and there was no association between this trait and sperm motility (r(2)=0.009) or with sperm density (r(2)=0.073). These results suggest that captive B. siebenthalae broodstock can be reproduced successfully.