Integrated Multi-Trophic Aquaculture (IMTA) of Abalone, Sea Cucumber and Seaweeds in an Intertidal Pond

Abstract

This study presents the establishment of an integrated multi-trophic aquaculture (IMTA) system in a marine intertidal pond using high value species such as abalone, sea cucumbers, and seaweed. Cage culture of abalone (Haliotis asinina) as the fed species, together with red seaweed (Gracilariopsis bailinae) as the inorganic extractive species, and sea cucumber (Holothuria scabra) as the bioremediator species in an intertidal pond, did not result in any significant changes in water quality as well as sediment organic matter. The abalone were cultured at two stocking densities inside net cages installed in the intertidal pond and fed with the red seaweed (G. bailinae) for 75 days. No significant gain in abalone shell length and weights were observed during the culture period, but survival rates remained high throughout the culture period. Minimal growth in shell length and weight observed were due to the large sizes of abalone used in the study, which were considered already sexually mature. On the other hand, twenty-two individuals of sea cucumbers stocked beneath the abalone cages grew from an average of 95.11 mm to 172.50 mm in length and 66.23 g to 302.17 g in weight. Daily growth rate in terms of length was 1.03 mm/d and in terms of weight was 3.15 g/d, which was considered fast as compared to other studies. The high survival rates of abalone in the present study coupled with fast growth rates of sea cucumbers as well as the lack of significant changes in water quality and sediment organic matter show the potential of integrated multi-trophic aquaculture of these high-value species in an intertidal pond. The farming system is also not dependent on wild algae that needs to be harvested in large quantities for traditional culture of abalone in cages.