Title Page
Contents
Abstract 9
1.0. Introduction 11
1.1. The offshore fisheries sector in Fiji 11
1.1.1. The tuna longline fishing industry 11
1.1.2. Challenges faced by the tuna fisheries industry in Fiji 12
1.2. Previous research that has been on-going to help the offshore fisheries industry in Fiji 13
1.3. Research using numerical methods to improve the efficiency of offshore fishing gear 14
1.4. Objectives 16
2.0. Methods and Materials 17
2.1. Numerical Method of analyzing longline fishing gear 17
2.1.1. Computer based longline simulation software 17
2.1.2. Model of fishing gear system 18
2.2. The Catenary Curve method 23
2.2.1. Korean Displacement Analysis design (KDA) 23
2.3. Secretariat of the Pacific Community analysis method 25
2.3.1. Pythagorean Theorem analysis 25
2.3.2. Secretariat of the Pacific Community - Mainline depth data 27
2.4. Experimental design 28
2.4.1. SimuLine computer software design 28
2.4.2. Korean displacement analysis 29
2.5. Longline gear specification - Simulation trials 30
3.0. Results 35
3.1. Longline gear analysis and hook depth graphical analysis 35
3.1.1. Longline mainline depth data 35
3.1.2. Longline hook depth data 37
3.1.3. Longline gear shortening ratio analysis 38
3.1.4. Graphical representation for the longline gear hook depth data 39
4.0. Discussion 43
4.1. Numerical Method of analyzing the tuna longline fishing gear 43
4.1.1. SimuLine computer software 43
4.1.2. Computer-based longline simulation trials 44
4.1.3. Mass Spring Model 46
4.2. Cable Structures 46
4.2.1. Catenary Curve principles 46
4.2.2. Korean Displacement Analysis, KDA 47
4.3. Pythagorean Theorem analysis 48
4.4. Dynamic longline fishing gear field research 48
5.0. Conclusion 52
6.0. References 55
Table 1. Theoretical longline mainline depths based on different shortening ratio (SR)... 27
Table 2. Specification for longline fishing gear for Simulation I 30
Table 3. Distance between buoys per basket for Simulation I 30
Table 4. Specification for long-line fishing gear for Simulation II 31
Table 5. Distance between buoys per basket for Simulation II 31
Table 6. Specification for longline fishing gear for Simulation III 32
Table 7. Distance between buoys per basket for Simulation III 32
Table 8. Specification for longline fishing gear, Simulation IV 33
Table 9. Distance between buoys per basket for Simulation IV 33
Table 10. Specification for longline fishing gear for Simulation V 34
Table 11. Distance between buoys per basket for Simulation V 34
Table 12. Comparative analysis of the Secretariat for the Pacific Community longline... 36
Table 13. Comparative analysis of the Secretariat for the Pacific Community longline... 37
Table 14. Shortening ratios for the Secretariat for the Pacific Community analysis,... 38
Figure 1. Longline gear in coordinate system 18
Figure 2. The Mass Spring Model : Forces acting on the rope element, the FB, buoyancy...(이미지참조) 19
Figure 3. Drag (CD) and lift (CL) force coefficients for the rope as a function for the angle of...(이미지참조) 22
Figure 4. Design of the Korean displacement analysis, KDA, for the longline fishing gear. 23
Figure 5. Dimensions for the Pythagorean Theorem analysis for longline fishing gears 25
Figure 6. The SPC, Simulated longline and KDA longline fishing gear hook depth data at... 40
Figure 7. The SPC, Simulated longline and KDA longline fishing gear hook depth data at... 41
Figure 8. SPC, Simulated longline and KDA longline fishing gear hook depth data at 0.9... 42