Friday, May 22, 2015

Types of aeration for your tilapia farm.

There are various forms of aeration you can use on your tilapia or other fish farm. Some of these are more costly than others, and some more efficient than others.Let's discuss these.

Here on our farm we used three types of aeration. The first is natural wind. This is by far the cheapest and easiest. Where we live in the northeast of Brazil, it is windy a good portion of the year. This always causes ripples in our lakes. Any time the surface of the water is moved or disturbed, air is getting into the water. This is suitable if you don't have many fish and a constant wind. In many places the wind is decreased at night. This is what happened here. We would wake to find our fish gasping for air on the surface. Trust me when I tell you, this is a depressing sight. The lack of air in the water is also increased if there is algae in your lake as this consumes oxygen overnight, thus depleting the oxygen available for your fish.

The second method we used was floating aeration systems. Depending on the depth of your lake, there are various models you can buy. Some need to be in at least 1.5 meters of water. It sucks water up from the bottom and throws it out the top. It is like a big fountain. We left ours on 24 hours a day, although I know some who only turn it on at night. It is worth bearing in mind the cost of your electricity. We benefit from a rural electricity rate and the cost was low to run these machines. We secured ours by running lines from one site of the lake to the other.

Another type of floating aerator is one with paddles. This can be used in shallower water, and this breaks the surface of the water with paddles. Like a paddleboat, as it digs down into the water air is being forced in.

Another type we used in our tanks, was a blower which was connected to several bubblers. Ours was actually a commercial vacuum which sucks on one side and blows on the other. We also used a compressor. These were connected through flexible hose to bubblers or disk aerators which we suspended about two feet into our tanks. These can also be used in a lake, however the pressure to push the air down to a depth you require may be too great. It is also worth mentioning here, the size of the bubbles produced is critical as that will determine the amount of oxygen being delivered in the water.

One problem we had was how to sink the hose and to keep it from kinking on its way to the disk aerators. We decided to use small lead weights which are used for diving, these we attached with plastic coated wire. Some times the solution to a problem isn't costly, it just needs to work.

There are also windmills which can be used. These move the water by sucking it up and returning it to the lake. This would be a good option if there isn't electricity available but have a steady wind. .

Sunday, May 17, 2015

How to Save Money on Your Tilapia Farm

Once you have your fish and your aeration (if using) sorted, the biggest expense is the food. There are things you can do to keep the costs down. It is these, I would like to discuss today.

Delayed feeding. This is a hard one for people to get their heads around, especially if your are dealing with your first lot of fish. The idea behind this is your young fish will eat the algae in your pond or lake. If you have your fish in a cage or in tanks, this isn't an option for you. This is for free swimming fish in a mature lake where there is plant life and algae growing.

It is worth mentioning at this point that in many areas tilapia are put into canals and rivers to help clean them and also keep the mosquito population down. In some parts of Asia, they will put the fish in the rice fields, which are flooded. When the rice is ready to harvest the tilapia are also harvested. These fish in the wild would find food, so don't think they will starve if you delay their feeding.

For commercial growing however it is worth noting that the faster they get to a saleable weight the faster you get paid. If you delay their feeding for the first month you will save quite a bit of money. There will be a reduction of weight compared to those which have been fed from the first day but not a large difference, about 10%. If you have a mature lake and enough water, this is an excellent option to try.

The second method is to feed every other day. Just as in humans the metabolism changes to the amount of food being provided. This is something we did in our second year with excellent results.

Although we fed our fish every other day. On the days we didn't feed them commercial fish food, we fed them duckweed. This reduced our food bill by half, a huge savings.

Friday, May 1, 2015

Different methods of tilapia farming

Here in Brazil, I have seen many different methods of farming tilapia so when someone tells you there is only one way, they are wrong.

The things which are necessary are water (of course), air (either natural or generated), and food. The health of your fish and the profitability of your business will be determined by those 3 factors and the quality of each of these things.

One couple in the village where we live, began their business in a roundabout fashion. They have a lovely home and small grounds. What they do have is a small stream which flows from the dunes down towards the sea. They dug out an area, about 15 feet across, laid cement and presto they had a lake/pond. The water was allowed to continue flow through of course. Into this they put their tilapia. In the center of the pond they had a aerator for the fish. They had a beautiful wooden deck surrounding the pool of water so you could see the fish. Their grounds also have picnic tables, a swimming pool and grassy areas.

They had started this as a 'fish and pay'. People, families in the main, would come and fish for fun, and when they caught a tilapia they would pay. I still think this is a great idea although in this area, it wasn't as successful as it would be in other areas.
Undeterred, this couple changed their plans. They continued to raise tilapia but found it more profitable to sell their fish to restaurants. They are one of the few people who allow their fish to grow big. The restaurants he sold them to wanted the fish at 2 kilos.

This couple also built a fully tiled kitchen prep area within their grounds. In here they prepared fish balls and other small appetizers which are frozen and then sold to the local stores. The advantage of this set up is everything is compact and easily managed. The running water is free from the dunes behind their house. The disadvantages are they are reliant on this water. If this dried up they would have to dig a well and pump it themselves. This isn't a big cost here, though. Because of the fish density and the time needed to grow their fish to 2 kilos, there is the potential for a disease which could wipe out their entire stock. There is also only one pay out which needs to last until the next harvest.

Another local tilapia farm has a completely different method. At this farm they had several shallow lakes, about 1.5 meters deep, spread across their land. In the center of each lake they had fixed aeration. They also had a small amount of water which flowed from one lake to another so they had a change of water. This was run by a couple of workers who lived on the grounds and the owner lived in the city and visited occasionally . They raised their fish to approx 450-500grams only. Then the lake was netted and the fish were sold. The reason for this is tilapia will begin to breed which causes problems to the profitability of your farm. Although the fish are relatively small when sold, they go to the local shops and to restaurants which make them into a casserole when the fish is cut up as opposed to serving someone a whole filet. At this farm we noticed they had netting stretched across the top. This was to discourage egrets, herons, and cormorants from eating the fish. Once their lakes were netted, the lake was drained and cleaned. These lakes are lined with compacted clay and once the water has drained or evaporated away the fish shit is scraped off and removed. Theirs is a year round business as they always have fish of different ages so they can provide a continuous supply. The advantage of this set up is there is a continuous supply and a continuing payout. The disadvantages are: The initial costs include the digging of the lakes and investment in the equipment for aeration, and considerable pumps to constantly move water around. This coupled with the employment of at least two people.

The next farm was some distance away and it is where we bought our used fish cages which we used for our second year of fish farming. This gentleman worked his business primarily on his own. He didn't own a body of water he merely put his fish in cages in a river. To feed these he used a row boat which took about 10 minutes to row out to the cages as they were secured in the center of this wide river. This way of tilapia farming has advantages and disadvantages. The advantage is the initial investment was small. All he had to buy was his cages, fish and food. And a row boat of course. The disadvantage is the potential of theft. A person wouldn't know if fish had been taken until either no fish came to the surface to feed or at harvest time when you realize your numbers are way down. This man knew many of the families who lived near this body of water and they all watched out for each other. We asked him if he was concerned about this and he had made it clear to people of the serious consequences of stealing from him. Here in Brazil people take action themselves and don't always rely on the police and the judicial system.

The system we used the first year had its advantages and disadvantages as well. There was a low start up cost because we already had the lake so we just needed to buy fish and food. Although we live in an area know for its wind we still needed to increase the aeration in our lakes. We bought two surface aerators. These were sufficient for our needs. The disadvantage was the harvesting of the fish. Because they had to be netted. Being novices to this we assumed the buyer would do this. In the end, everyone was doing it. Although not as we had planned, our harvest was spread across two days and we had the workers sleeping in hammocks over night here. We knew we had to become more organized and so we went and bought some used cages.