The selection of the type of trap to use will depend on the types of fish that you want to catch, where they live and how they behave (Figure 57). When you have decided on the fish you wish to take, you should then find out the type of bottom they prefer, their preferred depth and how they behave on the bottom. For example, if you live in a tropical area where there are reefs and you have decided to catch tropical snappers, you need to find out if they live in reef areas or in open water and at what depth. If the snappers live in reef areas, which they often do, it would help your proposed fishing operation if you knew whether they live near, under or over the reef. If other fishers in the area have used different gear such as handlines or nets, they may be able to give you some information on where the fish gather. If there has been no previous fishing, then look at the way similar fish living in other areas behave. Once you have a general idea of where they live, you can carry out your own tests with different traps and pots to find out the best ways to catch them.
When you know where your target fish or crustaceans can be caught and that they can be caught with traps or pots, you need to find out where to place the traps or pots on the bottom so that they have the best chance of getting good catches without being seriously affected by tides and currents. To place your traps or pots in the best fishing area, it is important to note the currents in the area and make allowances for them (Figure 58).
Trapping and potting fish, crustaceans and molluscs that are evenly distributed over the bottom is a special challenge. If you do not have any information on the bottom types that they prefer, how or when they migrate or their preferred food and/or shelter, it is very difficult to work out the best way to catch them. Again, it may be possible to find out about your target fish in other areas and use this information to carry out fishing tests in your area.
The key to successful fishing with pots and other gear is to develop the capacity to think as your target fish do, which means really knowing and understanding their habits, migrations, movements, feeding habits, etc. This capacity, once developed, will not only help you to find your target fish but will also allow you to make changes to your traps or pots that will increase your catch or the size and value of the fish or crustaceans that you take.
Diagram showing different traps to use
Considerable differences will be observed regarding living areas and conditions, feeding habits and behaviour of the targeted fish, crustaceans and molluscs. Shrimps and prawns, for example, normally live in burrows in sand or mud, away from reefs and rocks. There must be sufficient food for them in these areas to keep them there. Octopuses live in fairly open areas but need holes for shelter and an abundance of food. Commercial lobsters and rock lobsters normally live in cavities in or under reefs when they are not migrating to new locations, but they congregate where there is plenty of their preferred food.
In selecting your fishing area, you should look at how heavily it has already been fished and whether the numbers of fish have built up again after past fishing by either yourself or other fishers. Reefs, especially, should not be fished too heavily, as this will increase the time needed for recovery. Many reef fish grow quite slowly and if the numbers are reduced too drastically, a reef may take years to recover.
Many of the things you need to know about locating fish that live in mid-water or near the surface are similar to those for bottom species.
Most free-swimming fish species (known as pelagic species) tend to congregate around floating objects or above objects such as reefs on the sea bed. Feeding sea birds are normally a good indicator of where pelagic fish are congregating. In shallow waters, if your fishing grounds are generally flat and pelagic fish normally swim past, it is possible to place objects on the sea bed to entice them to stay in the area. Alternatively, fish-aggregating devices placed in mid-water or on the surface can be used to concentrate these fish.
Setting traps near reefs or where the fish live and in the direction they swim to