Netting Lakes wih Seine Nets
Lake Netting is considered as the most important part of aquaculture. Irony is, though it is one of the most important parts, it still gets ignored by users. This stage of fish faming always faces issues like, poor planning and shortage of equipments. Lake Netting is a simple process which involves following stages.

• To start with water cages or tanks are drained partially.
• Species needed for harvesting, are located inside the pond.
• Their movement is restricted.
• Selected fish is removed with the help of deep net.

Though process looks easy from outset; it requires high level of intensity on the field.
Drain and seine method is used for Lake Netting. In simple words they reduce water level by 20% to restrict fish movement and catch it with help of seine. Seine is basically a large fishnet that hangs vertically, with floats at the top and weights at the bottom. Pond is further drained till harvesting process is over. High temperatures and hot weather is not useful for harvesting. It should be done in cool weather, where temperature should be around 60 to 65 F. During summer season, when temperature rises above 80 to 90F, harvesting should be done in early morning. Make sure that cool water is near by to counter the heat. It becomes easy to capture fish when water level gets reduced considerably as fish gets saturated in small pond with low water level. Seine can be pulled by hands in case of small ponds but in large ponds trucks or other heavy vehicles are used to pull the seine. Seine is dragged from deep to shallow water, which is pretty obvious.
This method of harvesting is popular among users due to less availability of water and expensive pumping process. This method saves loads of water as there is no need to drain the ponds completely. Only 25 % draining is sufficient most of the times. Depending on production this method can be repeated number of times through out the year. In fact particular fishes are selected for harvesting during each turn; this type of harvesting is called selective harvesting. It is obvious that size of fish getting caught depends on size of the mesh. This will be discussed in details further in this article. Selective harvesting is particularly beneficial if harvesting is concentrated on large size fish. Fish is considered large when it is grown about 1.5 to 3 lbs. For maintenance fish culture tanks should be completely drained in every 7 years, according to owner’s convenience.
Harvesting location should be selected according to tried and tested norms. Ideally total size of the place should be twice than the size of the pond. Some norms are also there for selecting size of the seine. Ideally length of seine should be 1.5 times greater than width of the pond. Depth of the seine should 2 times grater than depth of the pond. Raw material used in seine construction should be nylon and polyethylene twine. Number 42 twine is considered best for this purpose.
Nature of seine also changes depending upon type of fish cultivated in the pond. For E.g. If owner wants to cultivate catfish then he must coat his seine with tar, plastic or other petroleum based material to avoid spines and fins of the fish getting entangled in the seine. As described earlier, size of the fish depends on size of the mesh. Size of mesh should never be less than desired limits, as small size of mesh creates greater water resistance and because of this it becomes difficult to pull the net. Harvest stock or live car is attached to net of the seine as it is pretty useful in the selective harvesting process. Due to this process number of fish that escapes through; gets reduced drastically.
At the bottom of the pond ‘lead line’ digs inside the mud while ‘mud line’ travels on the surface of mud, due to this reason weighted mud line is always preferred over lead line. While pulling the net; sufficient weight should be attached to mud line or lead line.
Weight should be good enough to keep that line down to the bottom. Top rope of the seine includes foam or plastic to make it float on the surface that’s why it is considered as float line. Seine nets with attached mud lines are pretty expensive to buy. Its cost depends on its length. There are many suppliers who will make the net according to your needs.
To make the seine net durable for long time it should be kept away from direct contact of the sunlight. Harvesting is far more effective in ponds, which have regular shape and gentle slope. To add to it drainage system of the pond should be up to the mark. The most important aspect for effective harvesting is smooth bottom surface, as smooth bottom   surface especially in shallow water is important to keep net away from damages and to make sure it’s getting pulled easily.
Due to stumps, rocks and other debris harvesting becomes next to impossible.
In such situation trap or corral kind of harvesting is used. In this process debris free area and corners are selected for harvesting and traps are set there which includes food for fish. Harvesting is done in every couple of weeks, depending on no of fish getting trapped. After harvesting fish should reach to the desired place and time for travelling should be as less as possible. If more time is required then fish should be trapped in live cages or live cars. Owner should look after water circulation in such cars. Number of fish held in such cars depends on temperature, as temperature increase no of fish should be reduced in live cars. Care should be taken that fish reaches its destination as soon as possible.