Proper Construction And Set Up Of Malaysian Fish Aggregating Devices (Unjam)

Abstract

This study was carried out with an objective of improving the durability of unjams and determining the rational arrangement and optimum density of unjams . Several experiments were conducted in coastal waters of Terengganu in the South China Sea to determine a safe anchoring power of unjams and parameters required for the development of mathematical models that could produce an optimum trapping efficiency .Experiment s on anchoring power showed sandy bottom giving the highest value of fixing coefficient ( 0. 953 ) , foll owed by muddy bottom ( 0. 903 ) , and sandy -mud bottom ( 0.731 ) . This value was found to be higher for two sandbags tied one behind the other than for two sandbags tied in one lump.The unjam's anchor was found to have a reserved fixing force of 67 . 34 kg , which is 93 . 86% in excess of what was required to anchor a n unjam in place .