Growth Rate and Sexual Performance of Domesticated Blue Swimming Crab, Portunus pelagicus (Linnaeus, 1758) in Earthen Ponds

Abstract

It is generally accepted that using domesticated aquatic animal is advantageous due to their adaptation to a captive environment. Despite previous reports on the domestication of the blue swimming crab, Portunus pelagicus (Linnaeus 1758), empirical data are lacking on the growth and sexual performance of domesticated individuals of this crab species. Thus, the growth and sexual performance were evaluated of domesticated P. pelagicus from the 1st to the 3rd generations. Domesticated crabs in the 1st (G1), 2nd (G2) and 3rd (G3) generations were reared for 150 days in 400 m2 earthen ponds at a density of 2 crabs/m2. Each generation had 3 replicates. The performance results showed that the mean final CW (11.4 cm) of G1 was higher than in G3 (9.9 cm), and G1 had a higher mean final BW (123.4 g) and SGR (4.8 % day–1) than in G2 (108.2 g and 4.7 % day–1, respectively) and G3 (102.9 g and 4.7 % day–1, respectively). The mean SR values in G1 (20.2 %), G2 (18.8 %) and G3 (18.3 %) were not significantly different. No significant differences were observed in mean FCR and productivity in G1 (5.8 and 94.1 kg/pond, respectively), G2 (6.6 and 82.9 kg/pond, respectively) and G3 (6.7 and 82.0 kg/pond, respectively). Sexual dimorphism in G1, G2 and G3 was observed at 60 days of rearing, with the sex ratio being 1:1 in each generation and 5.6 and 6.7 % of female crabs in G2 and G3, respectively, being berried in this period. In contrast, the berried females in G1 (17.6 % of females) were 1st found on day 90 of the rearing period. At day 150, the percentage composition ranges for yellow, brown and dark gray egg colors of the reared berried female crabs were 20.0 - 25.0, 40.0 - 50.0 and 25.0 - 40.0 %, respectively. These finding should assist in the future establishment of a selective breeding program that produces the 1st genetically improved strain of P. pelagicus possessing desired traits such as fast growth and high survival rates.
 HIGHLIGHTS
 
 Currently, the culture techniques for blue swimming crab (Portunus pelagicus) have not yet been fully established to expand the farms and increase productivity to a commercial scale
 It is generally accepted that using domesticated broodstock is advantageous due to their adaptation to a captive environment
 Successful aquaculture of P.pelagicus should rely on domesticated broodstock in which domestication improves reproductive and growth performances
 
 GRAPHICAL ABSTRACT