22
NOV
2016

The International Conference on Underwater Acoustic for Sustainable Fisheries in Asia (AFAS 2016).

Title: Detection and verification of Artificial Reefs in Northen Portion of Straits of Malacca by using Side Scan sonar – Dr. Azizi Ali (Research Officer)

THE INTERNATIONAL CONFERENCE ON UNDERWATER ACOUATIC FOR SUSTAINABLE FISHERIES IN ASIA. (AFAS 2016)

21-23 November 2016, Hakodate, Japan.

 

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DETECTION AND VERIFICATION OF ARTIFICIAL REEFS IN THE NORTHERN PORTION OF THE STRAITS OF MALACCA BY  USING SIDE SCAN SONAR

Azizi Ali1, Ahmad Ali2, Fadzil Akhir1, Aidy Muslim1, Shukri Arsad1, Fathy Kameel1, Roslan Latif1

1 Institut Oseanografi dan Sekitaran (INOS), University Malaysia Terengganu (UMT), ,Malaysia.

2 Southeast Asian Fisheries Development Center (SEAFDEC), Marine Fishery Resources Development and Management Department (MFRDMD),Fisheries Department, Chedering, Terengganu, Malaysia

Abstract

The current survey had been successful in providing answer to many issues pertaining to the artificial reefs (ARs) program in the west coast of peninsular Malaysia. The focus of detection and mapping is to verify their physical existence and stability on the soft and muddy seabed. Images recorded by means of side scan sonar (SSS) had been able to verify the condition of the AR modules, whether it still intact and firmly emplaced on the seabed or it moved and toppled by current or otherwise sink into the soft substrate below. In general, the survey we made in the study area found that most AR modules were standing firm emplaced on the seabed and functioning as what they had been intended.  Artificial reefs deployed in soft muddy seabed such that of west coast of Peninsular Malaysia were usually unstable and prone to sinking as compared to stable ARs deployed on hard sandy seabed such that of the east coast of Peninsular Malaysia.  However, the analysis conducted on SSS mages found that most of the AR modules deployed since 2007 could still be detected, whereby their heights above seabed being 2.0 meters on the average. This implied that the bottom portion of 1.6 meters had sunk into the substrate. It was expected that these  AR would be able to maintain the present height as they would not sink further since they were already resting on hard bottom layer, provided that there were not subjected to sedimentation. From the information provided by this study, future design of ARs modules can be improved in terms of stability after deployment and to avoid sinking. This study also had witnessed that SSS and digital global positioning system (DGPS) equipment to be the most suitable for ARs monitoring job, especially in the verification of coordinates, distribution of ARs over a large area and measuring their heights above the seabed.

Keyword : Artificial Reef, Side Scan Sonar, Peninsular Malaysia, Mapping