2010 Volume 3 Issue 2 Pages 185-192
Cultivation of Gracilaria fisheri was conducted in three abandoned shrimp ponds to obtain data of its growth and yield around Pattani Bay, southern Thailand. The experimental ponds were 0.64 (pond 1), 0.32 (pond 2), and 0.36 (pond 3) ha in area. The daily seawater supply naturally depended on the tidal level through an inlet/outlet gate. The seeding were conducted using thalli obtained from another farm by tearing into small fragments and then scattering into the study ponds with an initial density of 92 ± 28 g m-2. The seaweed fragments were torn and scattered every week until growth was observed. As the results, growth rates of G. fisheri were 9.2 ± 2.8 % day-1 at maximum and 4.6 ± 3.1 % day-1 in average before the first harvest at eighth weeks. Algal yields exhibited highest values after a cultivation period of 6 weeks in pond 1 (1,332.9 g m-2), 8 weeks in pond 2 (3,021.3 g m-2) and 8 weeks in pond 3 (2,107.3 g m-2). After half of the thalli in each pond were harvested, the remaining thalli were torn and culture was continued. From 20 weeks of cultivation, the cultivars yielded a total of 7,200 kg fw (pond 1), 14,000 kg fw (pond 2) and 18,700 kg fw (pond 3). Ice-ice phenomena and epiphytic Hypnea cervicornis were observed in pond 1. The cultivators have limited possibilities for expansion of G. fisheri cultivation because of holding on small areas in ponds. The results indicated that it is possible to employ vegetative propagation for the cultivation of G. fisheri in abandoned shrimp ponds, however expansion of the cultivation to open areas in Pattani Bay should be considered.
