Heat-induced triploids in : a strategic fish species for aquaculture and conservation.

Triploidization plays an important role in aquaculture and surrogate technologies. In this study, we induced triploidy in the matrinxã fish (Brycon amazonicus) using a heat-shock technique. Embryos at 2 min post fertilization (mpf) were heat shocked at 38°C, 40°C, or 42°C for 2 min.

Factors affecting secondary sex characteristics in the yellowtail tetra, Astyanax altiparanae.

This study interrogated factors which affect the appearance of secondary sexual characteristics, namely, fin spinelets (rigid dimorphic structure empirically associated with male sexual maturity in characids), in Astyanax altiparanae. Many variables such as the season of the year and several biotic components, including organism length, sex, phase of maturation, and the presence of gonads, were investigated. These factors were then associated with the physiological development of fin spinelets.

Flow cytometric analysis from fish samples stored at low, ultra-low and cryogenic temperatures.

Flow cytometry is a valuable tool in biomedical and animal sciences. However, equipment used for such analysis presents limitations at field conditions, suggesting then preservation procedures for future analysis at laboratory conditions. In this study, freezing at low (-20 °C), ultra-low (-80 °C) and cryogenic temperatures (-196 °C, i.

Reproductive cycle of the tetra (Characiformes: Characidae) collected in Amazonian streams.

A histological characterization of gonadal development in the tetra Astyanax bimaculatus was performed, aimed at determining its reproductive cycle in streams localized inside the Amazonian forest. Collections were carried out monthly from August 2017 to July 2018 at the Zoobotânica Foundation of Marabá, PA. Collected specimens were weighed and measured, and their gonads and liver were removed and weighed to calculate gonadosomatic and hepatosomatic indexes.