Induced out-of-season spawning of the mud crab, Scylla paramamosain (Estampador) and effects of temperature on embryo development

Treated with combined bilateral eyestalk ablation and maintenance of water temperature at 22.5±1.5 °C, mud crab Scylla paramamosain females with mature ovaries were induced to produce eggs outside the natural spawning season in subtropical southern China. Newly extruded eggs from a crab were incubated in vitro at 10, 15, 20, 25, 27, 30, 35 °C, respectively, and the embryonic development was closely monitored. Abnormal cell division was observed at temperatures 10 and 35 °C. At 15 °C, development remained at the gastrula stage by day 32 post-spawn, at which time the experiment was terminated. Hatching of in vitro incubated eggs occurred between 20 and 30 °C. An increase in incubation temperature from 20 to 25 °C reduced the incubation duration by 14 days, 2.6 times of that measured for a similar 5 °C increase from 25 to 30 °C. Embryonic development of S. paramamosain was divided into stage 0–10, and the duration of each stage was recorded for each incubation temperature. The information obtained allows accurate prediction of hatching time of female crabs incubated under variable temperatures. Larvae hatched from in vitro incubated eggs were reared to reach first juvenile crab stage and their dry weights were similar to those of larvae hatched naturally

Biologia reprodutiva de Macrobrachium olfersii (Wiegman) (Crustacea, Decapoda, Palaemonidae) coletados na Ilha de Santa Catarina, Brasil Reproductive biology of Macrobrachium olfersii (Wiegman) (Crustacea, Decapoda, Palaemonidae) collected at Santa Catarina's Island, Brazil

<abstract language="eng">The aim of this study is to characterize the reproductive features of Macrobrachium olfersii (Wiegman, 1836) from Santa Catarina's lsland. The animals were collected in freshwater streams of the Ratones Hidrografic Basin (site A1) and at the Peri's Pond (site A2). In the laboratory, the procedures of sexual differentiation were carried out to classify the individuais in males, females or ovigerous females, followed by the determination of total weight (g), quelipod relative weight (g) and total length (mm). The eggs were removed from the ovigerous females and counted. Sexual maturity and fecundity were analyzed based in the dimensions and number of eggs carried by ovigerous females. The water temperature on the capture sites varied from 17 to 29ºC throughout the months of study. A total of 503 individuais were captured, with 129 individuais from site A1 and 374 from site A2. The mean total size and length was 49.65 mm and 3.79 g for the males, 38.75 mm and 1.61 g for the females and 36.19 mm and 1.08 g for the ovigerous females. At the sites A1 and A2, the individual sexual maturity was reached with 27.3 and 21.2 mm of total length, respectively, while populational sexual maturity was estimated for the 45.0 to 50.0 mm class at site A1 and for the 30.0 to 35.0 mm class at site A2. The ovigerous females carried an average of 3464 eggs at site A1, and 1440 eggs at site A2. These reproductive features, presented by M. olfersii, show the species' plasticity, which can be associated with environmental variations, contributing to its reproductive success

Aspectos da reprodução de Palaemon pandaliformis (Stimpson) (Decapoda, Palaemonidae) no manguezal de Ratones, Florianópolis, Santa Catarina Reproductive aspects of Palaemon pandaliformis (Stimpson) (Decapoda, Palaemonidae) at Ratones Mangrove, Florianópolis, Santa Catarina

<abstract language="eng">Biometric and reproductive aspects of Palaemon pandaliformis (Stimpson, 1871) from Ratones Mangrove, Florianópolis, Santa Catarina, have been investigated. Individuals were monthly collected from August, 91 to July, 93 and the temperature and salinity registered. Biometry, sex-ratio, sexual maturity, fecundity and reproductive cycle have been determined. The temperature showed defined temporal distribution. This species presents animal reproductive cycle, relatively high individual and populational fecundity, and the ovigerous females were larger than males and other females of the same species