Reproductive performance and offspring quality of the first and the second brood of female swimming crab, Portunus trituberculatus

Although the swimming crab Portunus trituberculatus females can spawn up to 5 times during a reproductive season, only larvae hatched from the first brood are normally used for larval culture in commercial hatcheries. With the increasing price of swimming crab broodstock and decreasing availability of wild stock, there are increasing interests in the possible utilization of the second brood for larval culture. However, to date, no detailed study has been conducted to assess the reproductive performance and offspring quality from the second brood of female P. trituberculatus. The present study was conducted to compare reproductive performance and offspring quality of the first (1st) and the second brood (2nd) produced by female P. trituberculatus during a reproductive season. No significant differences in several important reproductive parameters, including percentage of females spawned, percentage of berried females successfully hatched, egg production per female and fecundity per unit body weight, was found between the first and the second brood. However, the first brood had significantly higher individual egg wet weight (1st = 40.54 µg; 2nd = 31.40 µg), egg dry weight (1st = 13.51 µg; 2nd = 10.55 µg) and hatchability (1st = 78.41%; 2nd = 66.04%), and significantly higher survival (1st = 88.31%; 2nd = 65.38%) and faster development (1st = 3.82 days; 2nd = 4.34 days) from zoea I to zoea II and showed better starvation resistance in newly hatched larvae (1st = 5.03 days; 2nd = 2.98 days) than the second brood (P < 0.05). Furthermore, the newly hatched zoea I from the first brood also had significantly higher total lipids, 16:1n− 7, 18:1n− 9, threonine (Thr) and arginine (Arg) contents, but lower levels of 18:0 and histidine (His) (P < 0.05) as compared to those of the second brood. These biochemical differences are likely linked to different larval quality of the first and the second brood.