Growth retardation and heavy mortality due to diseases has always been a major problem in shrimp aquaculture, both in the Philippines and in all other shrimp producing countries.
This is especially true in the culture of the Penaeus monodon or sugpo, which is native to the Indo-Pacific region. Due to this problem, all the shrimp producing countries in Asia resorted to the introduction of the Pacific white shrimp (Penaeus vannamei), which is native to the eastern part of the Pacific because of the availability of fully domesticated stock that are bred in specific pathogen free (SPF) facilities in the United States.
Many farmers in the Philippines now prefer vannamei due to its faster growth rate of 1.0 to 1.5 grams (g) per week compared to sugpo (1 g/week). Size at harvest is also more uniform for vannamei, thus reducing the need to sort the shrimps before delivery to the market. Since it is less aggressive than sugpo, vannamei can also be stocked at higher densities withoutworrying about cannibalism. Additionally, vannamei are tolerant of a wider range of salinities, making it more amenable to inland areas far from the sea.
Due to its tolerance of lower temperatures, vannamei can also be cultured in the cold season. More importantly, vannamei farms so far have not experienced massive outbreaks of White Spot Syndrome Virus or WSSV, which is known to cause mass mortality in sugpo. Survival rates for vannamei culture are thus higher than for sugpo, and the production level is more predictable.
In the hatchery, vannamei has the advantage of having a readily available stock of fully domesticated breeders from SPF breeding facilities abroad. Although the initial cost to import the breeders is high, the cost can be easily recovered due to the high and consistent survival rates of a well-managed hatchery compared to sugpo.
During grow-out, vannamei is relatively easy to culture. As with any aquaculture species, proper pond management is vital to ensure its profitability. First, selection of a good location for vannamei culture is a must. It must have an abundant, unpolluted supply of both freshwater and seawater; soil must be good quality, free from flooding; and the location must be close to the market.
Second, pond preparation must be thorough. As with fish culture, the pond is allowed to dry until the soil cracks. This may take from one week to one month, depending on the weather conditions. The black soil or muck must be removed from the pond bottom after each harvest, followed by application of lime (1 ton/hectare) to correct soil pH.
To ensure biosecurity in the vannamei farm, a tire bath, footbath, and hand wash must be provided. Crab fences and bird scaring devices should also be installed to prevent the spread of diseases from other farms. After sealing of gates and checking of dikes for seepages, teaseed powder (20 parts per million) is applied to get rid of fish larvae and juveniles which could feed on the vannamei. Inorganic fertilizers such as ammonium phosphate and urea is then broadcast all over the pond bottom to encourage the growth of natural food. Finally, the pond is filled with clean water up to a depth of 1 meter.
After admitting water for culture, vannamei post-larvae (PL) from BFAR (Bureau of Fisheries and Aquatic Resources) accredited hatcheries can be released into the water. These hatcheries can be found throughout Luzon, Visayas, and Mindanao. During stocking, it is important that the size of the PL is uniform. It should be at least at the PL 10 stage so that it is more resistant to transport stress. Stocking is done early in the morning or late in the afternoon, when the pond water temperature is cooler. Stocking density is dependent on the size of the pond and the number of paddle wheels available but generally, a density of not more than 100 pieces per square meter is recommended.
In Calatagan, Batangas—a top vannamei producing area in the country—vannamei is harvested after only 60 to 75 days of culture. Farmers in this town find vannamei culture highly profitable when they use the abovementioned pond management practices and as long as they follow the correct feeding management intended for vannamei.
One of the effective feeding management schemes used by farmers in Calatagan involves the use of Tateh Vannamei Feeds, which reduces the 100 to 120 days of vannamei culture period to just 70 days. The extrusion process undergone by Tateh Vannamei Feeds ensures easier digestibility by vannamei and faster conversion to meat. Newer pellet sizes are also available for the needs of vannamei at any stage of culture. In contrast to other feeds whose pellet sizes are either too little or too big, Tateh Vannamei Feeds have the appropriate pellet size designed so that the shrimp can readily carry the pellets while swimming and manipulate them with their feeding appendages.
As early as Day 1, Tateh Vannamei Feeds can already be used twice to thrice a day. For every 100,000 pieces of vannamei PL stocked, an initial feed of 2 kilograms is given. From this feed amount, additional 200 grams is added every day until Day 15 of culture. On the 16th day, a mixture of PO1B/ PO2B is used up to four times a day until an average weight of 5 g is achieved. From this weight until 10 g, the vannamei feed is shifted to PO3B, followed by PO4B or grower feeds until they reach 15 g. Finisher pellets are used for vannamei heavier than 15 g.
Aside from the body weights taken during sampling, the amount of feed given to vannamei are also adjusted based on the feed monitoring tray. A certain percentage of the total feeds per day is placed in the tray. Based on the amount of feeds left in the tray during the monitoring, the feeding rate for the next feeding can be adjusted up or down.
By properly following this recommended feeding guide and choosing the correct feed to use, feed costs in vannamei culture can be reduced and feed conversion ratio will be low for the entire culture period. Along with proper pond management practices, the use of Tateh Vannamei Feeds by farmers in Calatagan has enabled them to truly enjoy the profitability of vannamei culture.
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This appeared without a byline in Agriculture Monthly’s May 2018 issue.