Millennium gillnet effectiveness in Cirebon
Affected by colour transparency Affected by fish performance
Investigated through fish behaviour in relation to net panel
Investigated by fishing experiments operations
Fish behaviour on contrast color
Fish behaviour on specific white panel
Old white net, new white net and black
painted Old white net, new
white net and white painted
Descriptive analysis through percentage of
catch composition Capture process and
catch composition
One Way Anova Two Way Anova
•
Recommendation the effective and efficient colour of millennium gillnet
• •
Information of catch composition and capture process
Figure 1. The systematic diagram of this research
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2 LITERATURE REVIEW
2.1 The Description of the Gillnet
Gillnet is a wall of netting which may be set at or below the sea surface, on the sea bed, or at any depth between. Fish are caught by gilled, or by entangled as
they attempt to pass through the net, which may be classified as a gillnet, tangle net or trammel net depending on the manner in which the net is constructed and
the way the netting is hung Sainsbury, 1996. True gillnets are simply used to catch fish with body size of almost uniform
since the mesh size matched to the fish’s girth: the mesh size used depends on the species and size range being targeted. The net is constructed so that the meshes
are virtually square in shape and large enough that the fish can get its head through, but not its body, so that it becomes caught by at the gill cover on
attempting to back out. These nets are used for a wide range of species including small pelagic, cods and haddock, bass, and salmon Sainsbury, 1996.
Trammel nets are constructed of three panels of netting attached to the same framing ropes. A middle sheet of webbing of small, loosely hung mesh is rigged
between outside walls of large mesh. A fish striking from either side passes through the large outer mesh web and hits the small mesh netting which is carried
through the openings of the other large mesh webbing to form a sack or pocket in which fish is entrapped Sainsbury, 1996.
Various methods of setting gillnets are: 1 bottom set gillnet. Net may be set out end to end for up to a mile, but more usually are set in a pattern across or
around an area where fish are known to travel. Lead line maintains net in position on the bottom while the float line provides sufficient buoyancy to stretch the
twine. 2 Off-bottom gillnets. Net position is maintained by appropriate adjustment of buoyancy in floats and float line compared to the weight of the lead
line. 3 Surface drift gillnet. Surface floats are used; the lead line stretches the twine and the depth below the surfaces is adjusted by the length of the lines to the
floats Sainsbury, 1996.
In North Sulawesi, Indonesia several types of gillnets are operated i.e. drift gillnet, bottom gillnet, semi-encircling gillnet and shark gillnet in artisanal
fisheries. Drift gillnet mostly used nylon monofilament. The mesh size was ordinarily 1.75 inches; length of float line was about 40 to 80 m and 70 number of
mesh depth. The catch species were flying fish Cypsolurus sp., needle fish Tylosurus sp., barracuda Sphyraena sp. and sardine Sardinella sp. Reppie
and Lalamentik, 1999. Bottom gillnet is almost the same as the drift gillnet, the difference between
them just on the sinking force and buoyancy ratio, where the sinking power of the bottom gillnet is much bigger than its buoyancy, because it should laid stable on
the bottom. The catch consist of Acanthurus sp., yellow tail Caesio sp., black pomfret Formio sp., grouper Epinephelus sp., Chaetodon sp., emperor
Lethrinus sp., slip mouth Leigonathidae and trevally Caranx sp. Reppie and Lalamentik, 1999.
Semi encircling gillnets utilizing the onshore migration behaviour of fish in the tidal waters. The net material was nylon monofilament 1.75 inches, float line
about 90 m in length and 23 number mesh depth, sinking force much larger than its buoyancy. The catch species were slip mouth Leigonathidae, Lutjanus sp.,
Caranx sp., Lates sp., Lethrinus sp., Tylosurus sp., Pomadasys sp., Sphyraena sp. and Mugil sp Reppie and Lalamentik, 1999.
Shark gillnet was just a simple deep bottom gillnet for demersal species, included shark. This gillnet used to catch two specimen of “living fossil”
coleacanth Latimeria chalumnae in Menado Tua Dua. The mesh size limited to 5, 5.5 and 8 inches since only this size was available in the local market Reppie
and Lalamentik, 1999. Most of gillnet experiments in Indonesia studied the selectivity of types of
gillnet, such as drift gillnet, bottom gillnet and also trammel net. One of the examples of gillnet experiment in Indonesia was conducted in Pelabuhan Ratu,
West Java to determine selectivity of sweeping trammel net for banana prawn Penaeus merguensis using five types of trammel net which different in their
nominal inner mesh i.e. 38.1, 44.5, 50.8, 57.2, and 63 mm Yokota et al., 2003. The curve of selectivity resulted to a peak of 3.8 prawn length to mesh size lm
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