ABSTRACT This study investigated the anesthetic potential of the essential oil (EO) of Aloysia polystachya in juveniles of dusky grouper (Epinephelus marginatus). Fish were exposed to different concentrations of EO of A. polystachya to evaluate time of induction and recovery from anesthesia. In the second experiment, fish were divided into four groups: control, ethanol and 50 or 300 µL L−1 EO of A. polystachya, and each group was submitted to induction for 3.5 min and recovery for 5 or 10 min. The blood gases and glucose levels showed alterations as a function of the recovery times, but Na+ and K+ levels did not show any alteration. In conclusion, the EO from leaves of A. polystachya is an effective anesthetic for dusky grouper, because anesthesia was reached within the recommended time at EO concentrations of 300 and 400 µL L−1. However, most evaluated blood parameters showed compensatory responses due to EO exposure.

ABSTRACT The present study aimed to evaluate the effects of benzocaine and tricaine methanesulfonate on oxidative stress parameters of juvenile tambaqui tissues. Fish (n=80) were anesthetized with benzocaine (100 mg L-1) or tricaine (240 mg L-1) and two control groups were used (non-anesthetized fish and fish exposed to ethanol-only). After anesthetic induction 10 fish/anesthetic were euthanized after 3, 12 and 24 hours post-anesthesia and tissue samplings (gills, liver and brain) were performed. Samples were submitted to analyses of enzyme activity glutathione-S-transferase (GST), cellular lipid peroxidation (TBARS) and total antioxidant capacity (ACAP). ACAP increased in gills of benzocaine treatment after 12 hours. The liver showed a reduction in ACAP of tricaine treatment after 12 hours. Both anesthetic treatments showed an increase of ACAP at 24 hours compared to control group. The activity of the GST enzyme increased in the gills for treatments benzocaine and tricaine after 3 and 12 hours. Liver showed increased GST activity (benzocaine after 24 hours and tricaine after 3 and 24 hours). Lipid damage decreased in gills (both anesthetics) and brain (tricaine) after 24 hours. The results demonstrate that benzocaine and tricaine did not cause oxidative damage in juvenile tambaqui under the experimental conditions herein established.

The capture of juvenile shrimp as live bait for sport fishing has intensified, as has the trade of shrimp in different locations. The transport of shrimp to regions, other than those in which they are captured, is often poorly performed due to the lack of information regarding effective transport, resulting in high mortality of the transported animals. The aim of this study was to determine the optimum stocking density for the transport of juvenile Farfantepenaeus brasiliensis (weight: 5.53 ± 1.20 g) and to evaluate the effect of the addition of hydrated lime in the transport water. Four stocking densities were tested for transport (1, 2, 3 and 4 ind L-1). Following the analysis of the results obtained in the density experiment, the addition of hydrated lime (0.15 g L-1) in the transport water was also tested. Water quality and the final survival were negatively correlated with increasing stocking density. The results of this study demonstrated that the highest density that can be used to avoid mortality is 3 ind L-1 for a maximum period of 10 h. The use of hydrated lime in the transport water attenuated the observed effects on water quality parameters.

La captura de juveniles de camarón como carnada viva para la pesca deportiva se ha intensificado, al igual que el comercio de camarón en diferentes ciudades. El transporte de camarones a regiones distintas de aquellas en las que se capturan, a menudo se realiza en forma inapropiada, debido a la falta de información sobre el transporte eficaz, lo que resulta en una alta mortalidad de los animales transportados. El objetivo de este estudio fue determinar la densidad óptima para el transporte de camarón rosa Farfantepenaeus brasiliensis (peso: 5,53 ± 1,20 g), y evaluar el efecto de la adición de cal hidratada en el agua de transporte. Se hicieron pruebas con cuatro densidades de siembra para el transporte (1, 2, 3 y 4 ind L-1), y luego del análisis de los resultados obtenidos en el ensayo de densidad, se realizó una prueba con la adición de cal hidratada (0,15 g L-1) en el agua de transporte. La calidad del agua y la sobrevivencia final se correlacionaron negativamente con el aumento de la densidad de población. Los resultados de este estudio demuestran que la densidad más alta que se puede utilizar, para evitar la mortalidad en el transporte de camarón, es de 3 ind L-1 por un periodo máximo de 10 h. El uso de cal hidratada en el agua del transporte atenúa los efectos observados en los parámetros de calidad del agua.