A Eucheuma (Solieriaceae, rhodophyta) cultivation test on the south-west coast of Madagascar

Well established populations of Eucheuma denticulatum and E. striatum exist on the coral reef of the south west coast of Madagascar but natural beds are not dense enough to support high harvest pressure. A cultivation test was conducted on a 250 m2 module using the monoline method with 1560 seedlings of both species for over one year (weighings at 15 day intervals). E. denticulatum and E. striatum showed similar maximum growth rates (2.8 % d-1) occurring respectively in fall and in summer. For both species, minimum growth was observed during the warmest months (February-March). Mean growth rates, although relatively low, showed a high standard deviation, suggesting wide possibilities of strain selection. The preliminary selection experiment led to strains more resistant to breakage and having a growth rate up to 3.3 % d-1. The 'ice-ice' disease is also present in this area and affects the algae mainly from January to March. Mean carrageenan yield for E. denticulatum was 42.5% ± 2.3 and rheological properties were above industrial standards, with a highly elastic gel and were thus suitable for commercial applications. © 1993 Kluwer Academic Publishers.