At Aquaculture America 2003 (Louisville, Kentucky, USA, February 18-23, 2003), Dan Fegan, then with Thailand’s National Center for Genetic Engineering and Biotechnology and now regional technical manager of aquaculture for Alltech Biotechnology, Inc., which markets natural feed additives, talked about shrimp farming in Thailand.
During the question and answer session, Shrimp News asked Fegan if anyone in Thailand was following the Belize Aquaculture model of super-intensive, bio-floc shrimp production. He said: “There’s a lot of interest in it, but it’s too complicated. Pokphand has done some work on it, but pretty much the attitude is ‘If it ain’t broke, don’t fix it’” [implying that the current production system in Thailand was working just fine]. For a number of reasons (cost of energy, unlined ponds, skill levels), Fegan said the Belizian model might not be feasible within the Thai context.
No one knows how many shrimp farms are employing the bio-floc technology. The best examples of the of farms that have implemented the new technology are Belize Aquaculture, Ltd., in Belize, OceanBoy Farms in Florida, USA, and PT Central Pertiwi Bahari in Indonesia.
Central Pertiwi Bahari, a huge, integrated shrimp farm—hatchery, feed mill, power plant, laboratory, processing plant, cold storage and container vessels—produced 35,000 metric tons of shrimp in Lampung, South Sumatra, Indonesia, in 2004. The farm, part of Thailand’s CP Group, produces two crops a year from around 3,500, half-hectare ponds. In addition, it has nearly 130 experimental, intensive ponds of various sizes, where it tested the bio-floc farming before commercializing it on part of the farm.
The bio-floc trials were carried out in ponds of various sizes, shapes and types (lined and earthen) from mid-2002 to early 2004. Trial results showed that bacteria flocs were not easy to develop in earthen ponds. This could be due to suspended sediments caused by high aeration. In lined ponds, however, bacteria flocs developed. Vannamei can be stocked at very high densities (up to 300 PL/m2) in these ponds.
In small, lined ponds (0.2 ha) production was nearly 30.0 metric tons per hectare, compared with around 20 tons per hectare in larger ponds. This could be because bacteria flocs are much easier to manage in small ponds than in large ones. The record production was 49.7 metric tons per hectare from small (900 m2), densely stocked (280 PL/m2), round, lined ponds.
OceanBoy Farms, Inc.: At the First International Intensive Shrimp Culture Symposium in Belize (November 2004), Michael Mogollon, vice president of production, described OceanBoy Farms, an inland, freshwater, zero-exchange shrimp farm in Florida, USA, that uses bio-flocs in its maturation facilities, larval rearing raceways and growout ponds. Some excerpts:
Broodstock, hatchery, nursery and growout are all recirculating. Most of the water we are using on the farm is four years old, used over and over again for eight crops.
Nurseries are very important to us because we need to have all our juveniles ready to be transferred into the growout ponds by mid-March for the first crop and then again in mid-July for the second crop. We have a growout period from April through November and do mass stocking and mass harvesting. Over the course of one or two months, as we get ready for stocking, the nurseries are used to stockpile juveniles. The purpose of the nurseries is acclimation and holding. We use a lot of aeration, a lot of mixing, and a lot of constant feeding of the animals. The basic philosophy here is that constant feeding and water mixing keeps cannibalism in check. And if you are very rigorous about those two, you can come up with 90% plus survivals after thirty days of nursery culture.
After approximately thirty days in the nurseries, the juveniles are transferred to growout ponds for approximately 120 days, with aeration of approximately 25 horsepower per hectare, mostly paddlewheels, but with some aspirators in the center of the ponds. We inject oxygen into ponds on those nights when oxygen levels fall below critical levels.
We stock at 100 PLs per square meter and get two crops a year, from two, 120-day cycles. Growout survivals are 65%. We shoot for a 41/50 whole animals, although sometimes we let ponds go a little bit longer for clients who want larger shrimp. We get growth rates of around a gram a week.
Our hatchery produces very hearty PLs; they’re very active, vigorous, big for their age and extremely fit.
We’ve learned how to manage many water quality problems over the last few years, including high pHs, swings in pH, and nitrite toxicity. We do this by managing the algae and bacteria in the ponds to create a fairly stable environment for the shrimp. As other people have pointed out, when you do this type of culture, you’re really taking care of bacteria and the shrimp are along for the ride. Managing algae and bacteria is what we really focus on. When we get them right, the animals grow to their full potential.
We have not had any viral diseases in four years of operation.
In 2005, we are going to build an additional 16 ponds that will give us a total of about 80 hectares.
Question: How much are your construction costs per hectare?
Michael Mogollon: Our construction costs are very high, probably around $120,000 per hectare.
Question: What percent of the farm is taken up by treatment ponds?
Michael Mogollon: About 12%.
Question: How much protein do you use in your feeds?
Michael Mogollon: We start in the nurseries with 55% protein feeds and slowly bring that down to 31% in the growout ponds. We have to work on this because high-protein feeds mean more ammonia and more stress on the animals. We expect to lower the protein level in the feed every year until we’re down to approximately 22%.
Question: When is your growout period?
Michael Mogollon: We start stocking the growout ponds on March 15, and we harvest the last ponds during the first week of December.
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