Growth of Gracilaria sp. (Gracilariales, Rhodophyta) in brackishwater ponds at different stocking densities.

The specific growth rate (% per day) and net production rate (g per m2 per day) of Gracilaria sp. cultivated in net cages in a brackishwater pond were determined at different stocking densities (200, 250, 300 and 350 g/net cage of 0.5 m2). The mean specific growth rates for the duration of the culture period were highest at stocking densities of 200 and 250 g per cage (P0.05), but were significantly different from the other months (P0.05). Results indicate that Gracilaria sp. can be grown in cages in brackishwater ponds at stocking densities of 200 and 250 g/net cage (400 and 500 g per m2, respectively)

Vibrio harveyi and the 'green water culture' of Penaeus monodon

The 'green water culture' of the tiger shrimp, Penaeus monodon, is an innovative culture technique for the grow-out rearing of shrimps. This culture method involves the use of rearing water of tilapia for the rearing of tiger shrimp in grow-out ponds and on the polyculture of shrimp with tilapia. This culture technique was reported to present disease outbreaks attributed to luminescent Vibrio. To understand the possible mechanisms of luminous Vibrio control in the green water culture system several studies were conducted. This review summarizes the highlights obtained so far from these studies consisting of a) effect of rearing waters from tilapia culture and shrimp cultured with tilapia on Vibrio harveyi; b) estimation and preliminary identification of cultivable bacteria, fungi and phytoplankton flora associated with the 'green water culture' system and c) detection of anti-Vibrio harveyi metabolites from bacteria, yeast, filamentous fungi and phytoplankton indigenous to the 'green water culture' system

Effect of stocking density and duration on stunting milkfish fingerlings in ponds

Contribution No. 202 of SEAFDEC Aquaculture Department.The paper discusses the effect of stocking density and holding periods in stunting milkfish fingerlings in brackishwater ponds using twelve units of 144m2 earthen ponds. With 15, 20, and 25 fingerlings/m2 growth and survival rates were not significant (P2. Using the density of 20 fingerlings/m2 different stunting periods of 6, 9, and 12 months were tried. Survival and growth rates were not significant for 6 and 9 months stunting periods averaging 79.98% and 13.21 g. At longest (12 months) stunting period however survival was lowest (52.05%). In stunting milkfish fingerlings, a density of 15 to 25 pcs/m2 could be tried at a stunting period of 6 to 9 months in order to obtain an optimum survival of 81.7% and growth rate of 13.4 g

Polyculture of milkfish Chanos chanos (Forsskal) and the red seaweed Gracilariopsis bailinae (Zhang et Xia) in brackish water earthen ponds

Growth, net production, and survival rates of milkfish cultured with Gracilariopsis bailinae at two stocking density combinations (T1– 30 fingerlings 100-m−2 pond+1-kg G. bailinae 4-m−2 net cage, T2– 30 fingerlings 100-m−2 pond+2-kg G. bailinae 4-m−2 net cage) in brackish water earthen ponds over four culture periods were determined. The control (T3) was stocked at 30 fingerlings 100-m−2 pond. Specific growth and production rates of G. bailinae were also calculated. There were no significant differences in mean growth, survival, and net production rates of milkfish between the three treatments. Irrespective of stocking singly or in combination with G. bailinae, significantly higher mean growth and mean production rates for milkfish were obtained during the third culture period of year 1 than those obtained from the other culture periods. Survival rates were not significantly different among the four culture periods. There were no significant differences in mean specific growth and mean net production rates between the two stocking densities of G. bailinae. Significantly higher mean specific growth and mean net production rates of red seaweed were also obtained during the third culture period of year 1 than those obtained from other culture periods. The production of milkfish and red seaweed was higher during the dry season. Growth rates of milkfish was positively correlated with temperature and salinity, while net production rates were positively correlated with temperature and total rainfall, but was inversely correlated with dissolved oxygen. G. bailinae growth and net production rates were positively correlated with water temperature and salinity. Results show that milkfish can be polycultured with G. bailinae grown in net cages in brackish water ponds at stocking density combination of 30 fingerlings 100-m−2 pond+1-kg G. bailinae 4-m−2 net cage

An economic analysis of the modular pond system of milkfish production in the Philippines

In 1980, the annual yield of milkfish ponds in the Philippines was 800 kg/ha while the potential yield is estimated to be 2000 kg/ha. The modular pond system analyzed in this study can largely close the gap between actual and potential yield through more efficient use of pond capacity to increase the number of croppings up to 7 times in 1 year. Pilot-scale production using the modular pond system was done at the Leganes Research Station (LRS) SEAFDEC, Iloilo, and at three cooperating commercial farms. Scale of operation ranged from 2.7 ha to 7.9 ha. From 2 to 7 production runs were recorded with per hectare outputs ranging from 278 kg to 341 kg per run. Input costs were based on actual figures and the ex-farm milkfish price as P21.00 (4 to 6 fish/kg). The average return on investment and payback period for all sites was 68.81% and 1.25 years, respectively