Millennium gillnet has replaced the use of nylon gillnet that used before by fishermen to catch the same target of fish of same average size. The difference
between nylon gillnet and millennium gillnet is on the webbing material and net colour. The nylon gillnet is made of nylon multifilament, while the millennium
gillnet is made of multi-monofilament. The nylon gillnet colour is dark blue while the millennium gillnet colour is white transparent. According to Hovgard and
Lassen 2000, nylon multi-monofilament made of a number of monofile nylon thread or monofilaments in parallel. Multi-monofilament nets are generally
considered to be the most efficient as the use of thin parallel threads make the net softer than the monofilament or multifilament Hovgard and Lassen, 2000. It
makes the multi-monofilament nets more flexible underwater. Even though this type of gillnet has been accepted and well implemented in
Cirebon, the information of its use for catching pelagic fish, the capture process of this gillnet, and the effect of its net transparency is very limited. Therefore it is
necessary for understanding the catch performance and improving the effectiveness of millennium gillnet.
1.2 Problem Formulation
Principally, gillnet is wall or compounds of net which set out in particular pattern to barrier the school of fish in order that fish are gilled, tangled or trapped
Sainsbury, 1996. To improve its catching efficiency, there are some major parameters of gillnet to be considered i.e., colour of netting, dimension of
material, types of netting material and hanging ratio Hovgard and Lassen, 2000. On the millennium gillnet, transparency or colour is believed to affect the
catch efficiency and effectiveness. In gillnet fishery, transparency influences the visibility of this gillnet underwater, therefore less noticeable is necessary. Salmon
drift gillnet has less transparency than flying fish drift gillnet since it using the nylon monofilament, while flying fish gillnet using the multifilament net Nomura,
1985. Wardle et al. 1991 discussed the visibility of monofilament nets from a
physical perspective and show interesting patterns regarding the importance of object orientation in water as well as the differences in reflection in the air and the
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water. They further inferred that the visibility of nets depends on both the water colour and the colour of the seabed. Cui et al. 1991 used the light intensity
thresholds as an indicator of the fishing power of different coloured nets by comparing mackerel Scomber scrombus behaviour towards different coloured
twine. Considerable differences in colour selection thresholds observed for both a thin monofile thread and a thicker multifilament thread.
As new adopted gear, analysing a factor affecting the effectiveness on catch, in this case the net transparency is considered necessary. In order to analyse the
net transparency; in relation of fish as catch target, some approaches should be conducted. The study of behaviour often becomes the best way on analysing these
problems e.g. Wardle et al. 1991, Cui et al. 1991. Knowledge of fish behaviour, in relation to captures, can be acquired in different ways. Laboratory studies
informs that the fish behaviour patterns towards the gear or representations of gear-related stimuli can be described, and general behaviour relevant to the fish
capture process such as the swimming capacities of different species, can be studied Ferno and Olsen, 1994.
Meanwhile, as first step to understand the catch performance of millennium gillnet, the study of capture process is needed. This become necessary since the
information regarding this gillnet, which it was used from the first time until recent years is still limited. The capture process of gillnet can be determine
according to the ways of fish being retained in the net. The fish can be captured by being gilled, wedged, snagged and entangled Hovgard and Lassen, 2000.
For that reason, some studies are needed to understand the effect of transparency on fish behaviour towards net panel. Not just the effect of
transparency, some studies are also needed to obtain some information regarding the capture process of millennium gillnet as the way to understand the catch
performance of this net.
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