Once a pot or trap has been constructed, it must be prepared for the fishing operation. Buoys or floats will mark the location of the pot, so buoy lines and bridles must be attached to the trap or pot for setting and hauling. Appropriate rigging is also important to ensure that the pot or trap lands the right way up on the bottom. The length of the buoy line will vary with the trap type, the tidal range and currents in the fishing area. The usual length of the buoy line is about one-and-a-half times to twice the water depth being fished, but may be greater if there are strong currents. Floats or buoys are attached to the line so that you can find your trap or pot again and pick up the buoy line to remove the catch. The size of buoys or floats varies with the depth and current. Flags, radar reflectors and radio beacons are sometimes attached to buoys to make them easier to find. The knots used to attach floats and traps to ropes must be simple and stay intact. Working with rope and tying knots are not covered in this manual, as other FAO manuals cover these topics in some detail.
Depending on the fishery, traps and pots are rigged to fish on individual lines (Figure 59) or are linked to a main line on the bottom with a buoyed line and an anchor at one or both ends (Figure 60). Such arrangements are called setting "in line" or "in row", or sometimes, setting "in gangs".
Rigging of traps - individual
Rigging of traps - in line or row
As stated earlier, some traps and pots (e.g. eel traps, octopus pots, pelagic traps and some Caribbean traps) do not require bait for their operation but attract fish by appearing to provide shelter. However, in most cases the placing of bait in the trap or pot gives an added reason for the fish to enter.
The relationship between the funnel and the positioning of the bait is critical in getting good catches. The bait has to be positioned so that a fish entering to take it cannot back out through the funnel or find the funnel exit and escape. Depending on the type of fish being targeted, the bait is placed off-centre from the funnel and well to the back of the trap. However, it is important not to place the bait so far towards the back that fish are attracted away from the funnel. The best position for the bait in the trap or pot can be found by trial and error or by following the indications given with the trap or pot design. It is important to use bait that is attractive and to place it in the trap or pot in a way that reduces escape. To achieve this, try to imagine how the target fish react.
Solid baits (e.g. whole fish, animal bones) are often secured directly in the capture chamber. Bait in small pieces (e.g. pilchards, chicken heads, minced fish) is usually placed in a small container or bait box (Figures 4 and 5, p. 4 and 5 and Figure 49, p. 44) made from wire or nylon mesh, or in plastic or metal containers (bait savers) that are perforated to allow the odour of the bait to escape.
Some unusual baits have sometimes proved to be quite effective in certain fisheries.
These include papaya wood, porous bricks soaked in fish oil and even shiny stones. If you do not have any conventional bait available it is worth trying some of these unusual baits. As a general rule, bait made from fish, especially oily fish, is the most reliable and effective.
A good bait is:
A key factor in successful fishing with traps and pots is the location in which you set them. This positioning will depend on the types of fish you are targeting. It is very important that you develop the capacity to understand how the fish will react to your trap or pot. For fish that live under reefs or rocks and do not venture far from their shelter (e.g. rock lobsters, tropical cod), you must place the trap close to where they are sheltering. Some types of fish (e.g. coral trout, trevallies) swim over the tops of reefs and rocks. In these cases, taking into account the tide and current, the location of your trap is critical and may make the difference between a good catch and no catch (Figures 58, 61 and 62).
Other fish and crustaceans live in burrows in the sand or mud. In this case it is important to set your pots or traps in areas where there are the greatest concentrations of the animals and where any current will not carry the smell of the bait away from your target.
In cases where your target fish are attracted to the trap or pot for shelter, you should find out where they spend most of their time and where they are likely to seek shelter.
Traps and pots should not be set so close to each other as to affect individual catch rates. The distance between traps and pots depends on the bottom type, the number and distribution of your target fish in the area, the attractiveness of the bait and the size of the trap or pot. There is no easy way to find the best distance and so you will need to experiment by seeing whether the catch rate increases or stays the same as you set the pots further apart.
The location of the traps and pots is marked with a buoy attached to the hauling line. Where there is a possibility of theft or when the gear is set in an area where there is shipping traffic, you might not be able to use surface buoys. In this case, you will have to locate traps by using triangulation with land or sea marks and you will have to retrieve the pot using a grappling hook dragged along the sea floor.
If the setting comprises several pots or traps attached to a single line, a larger float is usually placed at one or both ends and marked with a flashing light. If the location is away from land, a radar reflector or a radio beacon may be attached to the buoy to make it easier to locate.
Setting traps near reefs against the tide
Setting traps near reefs with the tide
As with many aspects of trap and pot fishing, fishing time will vary with the target species and their behaviour. Some fish feed actively only at night so, if you are using baited traps, night fishing is indicated. Other fish feed mainly during the day and can only be taken during daylight. Unbaited traps and pots such as the pelagic fish trap (Figure 35, p. 34) and those used in the Caribbean should be set for short periods at times when the target fish are seeking shelter.
The duration of each set will also vary with the behaviour of the target fish and the durability of the bait. When fish are feeding very actively, the fishing time of each set may only need to be a few minutes. Some tropical snappers off northern Australia can be taken in only 30 minutes between setting and hauling. In other fisheries, the soak time may be several days depending on the fish and conditions. It has been found in the Caribbean that a soak time of two to three days is usual and that after four to five days the catch may actually decrease, possibly because the fish learn how to escape from the trap.
Normally, depending on local conditions, traps are hauled every one to three hours in shallow waters, while at greater depths they are frequently set for longer.
In some areas, new traps and pots are soaked in the water for some time before they are used for fishing to eliminate any foreign odours coming from the materials used or, in the case of cane and wooden pots, to eliminate any trapped air.
As with other fishing gear, special care must be taken to reduce the number of traps and pots lost during fishing operations. The replacement of those lost can be a financial drain on your operation. In addition, the lost gear may continue to attract fish for days or months, which is wasteful and reduces fish stocks without any return. In some fisheries, legislation has been passed to make it obligatory for fishers to design their gear with a section that will corrode quickly and make an opening for fish to escape from lost pots.
Once the traps or pots have been found and the hauling line secured, they are hauled aboard and emptied. Hauling may be done by hand or by a mechanical hauler. In the case of hand hauling, the gear is usually brought alongside and the trap emptied. If it is to be set in the same location, it is rebaited (if bait is being used) and replaced in its location on the bottom. If the gear is to be shifted to a new location, it is hauled on board after the catch has been taken out and stored until the next set.
Modern trap and pot vessels usually have a mechanical pot hauler fitted and a pot tipper on the gunwale (Figure 63).
A pot hauler and tipper