A recirculating incubation system for hatching small batches of fish eggs

Abstract

This paper describes the design, construction and evaluation of the capacity of a re-circulating incubation system for hatching small batches of fish eggs. The system consisted of forty eight 50-mL plastic centrifuge tubes as incubation units connected to UV-sterilized water supply. A 1.0-mL serological pipette was extended through a rubber stopper to the bottom of each centrifuge tube to provide gentle rolling of eggs. Water flowed out of the incubation unit through a small section of glass and then plastic tubing inserted through a second hole in the rubber stopper to a PVC drain manifold. The system was used to hatch successfully small batches of artificially fer-tilized, naturally spawned eggs (50-150) of isolated blue tilapia Oreochromis aureus females. The best hatching success (36%) was achieved at the stocking density of 50 eggs/tube. The poor hatchability was attributed to low egg viability.