Floating cage nursery culture system for Penaeus monodon

Abstract

The use of floating cages as nursery for Penaeus monodon postlarvae was tried at the Batan, Aklan Substation of the SEAFDEC Aquaculture Department. The cages were made of bamboo and measured 2 × 5 × 1.5 m (effective volume 10 m3) with cement-coated styrofoam sheets as floats. Two nets were installed inside a cage. The outer net (3 mm mesh size) protects the inner net (0.5 mm mesh size) from floating debris in the bay. The cages were installed offshore where water depth was at least 2 m during the lowest tide, and were attached to bamboo posts by metal rings. Postlarvae were stocked at ages ranging from PL5 to PL16. Feed consisted of raw ground fish paste applied to a feeding net which also served as substrate. Average survival based on 25 production runs was 40.98% after 2 to 3 weeks of culture. Stocking density ranged from 4,000 to 16,895 PL/m3.

Unlike nursery tanks, this system is easier to manage and needs no aeration and pumping, thus reducing operational costs. Floating nursery cages should be located in protected areas; they can also be installed inside fishponds.