Hatchery production of European lobster (Homarus gammarus, L.): Broodstock management and effects of differentt holding systems on larval survival

The biometry of wild berried females was collected during an entire reproductive season at the South- Wexford Lobster Co-op hatchery in Nethertown, Ireland. Second degree regressions between total body weight (TW, g) and carapace length (CL, mm) (TW=CL2 -36.675CL+1793.2, R2=0.9022) and number of “weaned” larvae and carapace length (Larvae number=1.217CL2–21.777CL-5281.1, R2 =0.743) were observed. Afterwards, berried females were divided according to two variables: 1. holding system: recirculating system (Rs) vs barrel (Bar); 2. CL size: <101 mm (A), 101-120 mm (B), >120 mm (C). The total weight of larvae (212.5 vs 92.4 g) and their numbers (7788 vs 5679) were significantly higher for the largest females than for the smaller sizes (P<0.01). The maximum survival rate of larvae (77.86%) was noted for initial stocking density <1000 individuals/hopper, but the optimal stocking density for management purposes in the hatchery is higher (2001-3000 individuals/hopper).