Community-based coral aquaculture in Madagascar: A profitable economic system for a simple rearing technique?

Abstract

Since a couple of decades, coral aquaculture has been developed in many countries to face an increasing live coral market and to support conservation of endangered natural coral reefs. To evaluate the potentiality of community-based coral aquaculture in Madagascar, we experienced suitable farming techniques using the species Acropora nasuta and Seriatopora caliendrum. Survival and growth rate of the nubbins were monitored during wet, warm and dry, cold seasons. To determine economical feasibility, the coral market was investigated and the yields were also calculated using the technical, biological and social parameters of the production. Coral nubbins were reared in situ at appropriate conditions. Coral nubbins reared during the wet, warm season showed a final survival rate of 67 ± 6% and 57 ± 4% respectively for A. nasuta and S. caliendrum, while in the dry, cold season, the survival rates were of 85 ± 7% and 69 ± 1% respectively. A. nasuta had a significantly higher survival rate than S. caliendrum during both seasons. During the wet, warm season, growth rates were 0.46 ± 0.16% d− 1 and 0.54 ± 0.16% d− 1 respectively for A. nasuta and S. caliendrum. In the dry, cold season, A. nasuta had 0.63 ± 0.18% d− 1 of growth rate, while S. caliendrum grew 0.65 ± 0.15% d− 1. Significant difference was observed between both species during the wet, warm season, but not during the dry, cold season. Furthermore, both species grew faster during the dry, cold season. These results are in the range of reference values for corals. The activity can be profitable from 25 coral nubbins sold per month. Profit can already be perceived from the second year and a total of more than EUR 27,000 earned after 5 years of developing project, for an initial investment of EUR 1978. Marine animals wholesale companies and biodiversity conservation NGOs seem to be the appropriate clients for this form of aquaculture on Madagascar.