Reproductive traits of the lake prawn Palaemon paucidens De Haan, 1844 (Decapoda, Palaemonidae), from Goesan Lake, South Korea

Abstract

The reproductive biology of Palaemon paucidens De Haan, 1844, from Goesan Lake, Korea, was investigated during the period May 2010-October 2011. The proportion of females was significantly greater than that of males (female : male ratio, 1 : 0.7). The gonadosomatic index (GSI) varied monthly, reaching a maximum in May and a minimum in September. 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 eggs, 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 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 the eyed stage. Reproductive output was 0.20 ± 0.04, based on dry weights in early egg stages. The results were compared with other studies of P. paucidens in Sukdang Lake and other species of palaemonids in different habitats. This comparison reveals intra- and inter-specific variations in reproductive traits of palaemonid shrimp. The phenomenon is suggested to be a result of adaptations to different environmental conditions. Variation in reproductive traits within the same species reflects a different life strategy adaptation in species that will require a different approach in fisheries management. Information on intra- and inter-specific variation in reproductive traits is important to be used as one basic issue of biological information to support an effective fisheries management of P. paucidens, which has been locally exploited in Korea and Japan.