Reproductive biology of lake prawn Palaemon paucidens De Haan, 1844 (Caridea, Palaemonidae) from Goesan Lake, Korea

Abstract

Reproductive biology of Palaemon paucidens De Haan, 1844 was investigated at Goesan Lake, Korea from May 2010 to October 2011. The proportion of females was significantly greater than that of males (female: male ratio, 1:0.7). The length-frequency distribution showed that females were predominant on larger class size than males. Significant differences on slopes of body weight versus carapace length linear regression between sexes indicate sex-specific differences in allometric growth. The gonadosomatic index (GSI) varied monthly, reaching a maximum in May (11.4) and a minimum in September (0.3). Monthly variations in the proportions of ovigerous females showed peaks in April and May. The highest values of the GSI coincided with the breeding period of P. paucidens (April–August). There was no significant difference between the mean GSI of females with non-eyed and eyed egg, indicating that P. paucidens is a non-consecutive breeder. There was a significant correlation between the number of eggs and the carapace length at early egg stages. There was no significant difference in the slope and intercepts of the regressions of the number of eggs versus carapace length between females carrying non-eyed and eyed egg stages, indicating that there was no brood loss during the incubation period. Egg volume increased significantly (by 75.6%) as eggs developed from the non-eyed to eyed egg stage. Based on dry weights in early egg stages, reproductive output was determined 0.20 ± 0.04, smaller than previous study on same species and different with other palaemonid studies indicating intra- and inter-specific variation on reproductive traits within P. paucidens on different geographic areas and among palaemonid shrimps that lives on different habitat.