|Better Farming Series 35 - Better Freshwater Fish Farming: Further Improvement (FAO, 1986, 61 p.)|
96. Now that you have several fish- ponds, you can grow fish all year round.
97. If you put baby fish in different ponds at different times, you will harvest them at different times. This way, you will not harvest too many fish at the same time and you can harvest fish all year round.
Harvest fish all the year
98. If you have three ponds and a good supply of baby fish, you can stock each pond in a different month of the year and harvest each pond six months later. The diagram on the next page will show you how to harvest and stock three ponds.
99. If you need help, your extension agent or fishery officer will be able to give you good advice on when to put in the baby fish and when to harvest them.
Take advice from extension agent or fishery officer
100. You can further improve your fish- farming by growing only male tilapia in your ponds. Male tilapia grow bigger faster because without baby fish to feed, all the food that you put into your ponds will be eaten by the male fish.
101. If you decide to grow male fish, use fish that are at least 10 centimetres long so that you can harvest them sooner. A male fish of this length will be fully grown in three to four months.
102. If you have a nursery pond, you can get male fish from it. The drawing below shows you the difference between male and female tilapia.
Difference between male and female tilapia
103. If you do not have a nursery pond, you may be able to buy male fish from another fish farmer or from a fish culture station.
104. Items 91 to 98 in Booklet No. 27 and Items 114 to 144 in Booklet No. 30 tell you how to harvest your fish and what to do with them after they have been harvested.
105. Here are some other things that you should know about harvesting to improve your fish- farming further.
106. With bigger ponds and more ponds, you will harvest many more fish. You must be sure, however, that you will be able to use, sell or preserve all of the fish that you harvest.
107. If you will have too many fish to use, sell or preserve by harvesting all of them at the same time, harvest them at different times. You can harvest a few of your fish at two or three different times.
108. You can do this by draining part of the water from your pond and collecting only some of the fish on the first day you harvest. When you have used, sold or preserved these fish, you can harvest more of them.
drain all of the water and collect part of the fish
109. When you are ready to harvest the last of the fish, drain all of the water from the pond and harvest the remaining fish. First, collect the baby fish for your nursery pond and then collect the big fish.
Drain the water
110. If you have built a monk for the outlet of any of your ponds (see pages 18 to 23 in this booklet), you can harvest your fish in two ways:
· you can harvest inside your pond just in front of the monk
· you can harvest outside your pond after the fish have passed through the monk.
111. To harvest your fish inside the pond, remove the wooden boards from the monk one row at a time. Each time you remove a row of boards from the monk, be sure to put the screen back on top to keep your fish from getting out.
112. When the water is partly drained from your pond, harvest part of the fish from the water just in front of the monk.
113. When you are ready to harvest the rest of your fish, continue to take out the boards one by one. However, put back the screen each time until the pond is empty. When all of the water is out, you can harvest the remaining fish. First collect the baby fish and then collect the big fish.
Harvesting inside the pond
Muddy water Is bad for baby fish. If you must walk in the water to collect the baby fish, let a little clean water flow through the pond to keep it from getting too muddy.
114. When you have a monk it is sometimes easier to harvest outside the pond using a screened wooden box to collect the fish, after they have passed through the monk.
115. The drawings below show you how to build a harvesting box, using strips of wood and screen, and how big it should be.
116. When you are ready to harvest your fish, put the harvesting box in the outlet ditch outside your pond at the end of the pipe from the monk. Make sure that the pipe is well inside the harvesting box so that the fish will not get out.
Using a harvesting box
117. Now, take the screen out of your monk and remove the wooden boards one row at a time. The water will begin to flow out of your pond.
118. Do not put back the screen. When the level of the water in your pond is low enough, the fish will begin to pass over the boards and through the monk to the harvesting box. When they are in the box, you can collect them easily.