Study on an integrated eco-aquaculture system for rearing the yellow seahorse, Hippocampus kuda Bleeker

Abstract

Seahorse aquaculture is challenged by insufficient feeding supply and lack of biological and nutritional knowledge, resulting in low survival rate and poor economical profitability. We report here an integrated eco-aquaculture system in which the yellow seahorse and its natural prey were co-cultured with fertilized water and seaweed in cement ponds. In the first stage, urea (10 g m−3) and chicken manure (50 g m−3) were used to fertilize the cultured water, 5–7 days later, rotifer and micro-crustaceans were flourishing. Then, seahorse juveniles were stocked at 200 ind m−3. After 2 weeks, seaweed Gracilaria lichevoides was transplanted into the ponds to regulate water quality, light and to provide holdfast attachment for seahorses. The optimal density of G. lichevoides was controlled between 0.5 and 2 kg m−3. The introduction of seaweed provides the habitat for natural food of seahorse. Within the cluster of the seaweed, small crustacean density was over 450 individuals per 100 g of fresh weight. Initial size of seahorse juvenile was 1.03 ± 0.091 cm, After the 146-day rearing period, seahorse survival rates were 70.8%, 57.7% and 42.5%, and body standard lengths were 11.33 cm, 10.84 cm and 10.04 cm in the integrated eco-aquaculture system (GFA) and in monoculture systems of FA (fertilized + feeding) and BA (only feeding) respectively. This system incorporated traditional Chinese aquaculture technique in which feedings nature food organisms were cultivated by fertilization and ecological regulation. Results from these preliminary experiments suggest that the integrated system could be technically feasible, suitable and exemplary.