Human and fish behaviour around Fish Aggregating Devices (FADs) in Indonesia

Utama, Andria Ansri (2024) Human and fish behaviour around Fish Aggregating Devices (FADs) in Indonesia. PhD thesis, University of Glasgow.

Abstract

Deep-water anchored Fish Aggregating Devices (FADs) are utilized to attract fish and support tuna fishing operations in the Indonesian Indian Ocean. Various demersal/reef and pelagic fish species at different developmental stages naturally aggregate around these devices, creating artificial resource patches in the pelagic habitat. These artificial patches are advantageous to fishers because they can be located more easily and quickly than free-swimming schools, thus minimizing search time and operating costs. Introduced in the late 1990s, this method has grown rapidly and become the dominant practice in artisanal, medium, and large-scale industrial tuna fisheries.

The medium-scale tuna handline fishery off the South Coast of Java (Indian Ocean) employs FADs to support their fishing operations in offshore waters. Fishers can easily switch between fishing gears during a single trip, adapting to sea conditions, catch success, and the behaviour of the fish. The weak management system of this fishery results in limited information about their fishing behaviour and the spatial distribution of fishing effort. Additionally, collecting scientific data on fish behaviour associated with FADs in the pelagic ecosystem is challenging due to the difficulties in accessing their natural environment, particularly in locations where FADs are usually distributed far from coastlines and over broad offshore areas.

This thesis combines quantitative and qualitative research techniques to investigate the behaviour of fishers and fish associated with FADs. Low-cost satellite GPS trackers were used to monitor the movements of individual tuna handline fishing vessels. This approach effectively identified fishers' actual fishing grounds, fishing activities, and the distribution of FADs. Additionally, interview techniques were employed to identify the variability of fishing behaviours and to explore the decision-making processes and motivations behind them. Both methods also allowed for the identification of illegal fishing activities.

Fishers' knowledge of tuna behaviour around FADs, acquired through their extensive practical experience, provides crucial information that complements scientific observations of FADs. A novel technique integrating acoustic surveys and a remotely operated vehicle (ROV) equipped with a stereo-camera system allows for the characterization of fish communities, behaviours, and densities around FADs. This approach provides valuable data to mitigate the impact on non-target species associated with FADs.

This study demonstrates the importance of integrating diverse knowledge sources, including scientific knowledge and local knowledge, to obtain reliable information on fisher and fish behaviours.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Supported by funding from the Indonesia Endowment Fund for Education, The Indonesian Ministry of Finance.
• Subjects: B Philosophy. Psychology. Religion > BF Psychology; Q Science > QH Natural history > QH301 Biology; S Agriculture > SH Aquaculture. Fisheries. Angling
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Funder's Name: Indonesia Endowment Fund for Education
• Supervisor's Name: Bailey, Dr. David, Killen, Professor Shaun, Wilcox, Dr. Chris and Hopkins, Dr. Charlotte
• Date of Award: 2024
• Depositing User: Theses Team
• Unique ID: glathesis:2024-84638
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 29 Oct 2024 09:57
• Last Modified: 30 Oct 2024 09:55
• Thesis DOI: 10.5525/gla.thesis.84638
• URI: https://theses.gla.ac.uk/id/eprint/84638