Shark Depredation and Unwanted Bycatch in Pelagic Longline

More documents

Recommendations

Info

Shark Depredation and Unwanted Bycatch in Pelagic Longline Fisheries Table 2.1. Generalized gear characteristics that may affect shark interaction rates for nine pelagic longline fisheries. Pelagic Longline Fishery Gear Characteristic Australia Tuna and Billfish Chile Artisanal Mahi Mahi and Shark Chile Swordfish Spanish system I American-style Fiji Tuna Fishing season All year Sharks year-round, mahi in austral summer March - December All year Main line length 60 km 2.7 – 3.6 km 83 km 65 – 102 km 65-93 km Main line deployment Shooter Manual Manual Not known Trip duration 4 days 3-4 days for mahi targeting trips 9-30 days Trips per year Not available Not known Sets per trip 3 7-25 Hooks per set 950 100 - 350 1500 1200 - 2000 2300-2500 Wire leader (trace) used? Typical min depth of hooks Typical max depth of hooks No (prohibited) No when targeting mahi, yes when targeting sharks Yes or use poly-propylene 33 m 9 m 58 m 50-180 m 77 m 54 – 72 m 70 m 300 m Distance between buoys 360 m 18-36 m 4.5 km Variable 90-700 m Yes No Float line length 12 m 0 m 18 m 15-16 m Branch line length 19 m 9.1 m 8.2 m 16.5 m 15-24 m Branch line material Nylon monofilament Nylon monofilament Polypropylene Nylon monofilament Not known Hooks per basket (between buoys) 9 5-10 25-35 Timing of soak Variable Day Night Day for small vessels, night for distant water vessels Lightstick frequency Variable None 1 -4 per hook None on small vessels, yes on floats for large vessels Weight size and location Variable, usually none None when targeting mahi, weighted swivels when target sharks 60 g at connection of mainline and float line 80 g at connection of mainline and float line, and 65-76 g swivel at top of leader Not known Hook type J and some circle hooks of various sizes J 0,1,2,3 (10 o offset) J17 Ancora (no offset) J18 Ancora (no offset or 10 o offset) J Mustad 9 (10 o offset) Not known Bait type Squid, pilchards, jack mackerel,yellowtail, scad, anchovy, redbait, blue and other mackerel, tooth whiptails, and redfish. (Live bait =11%) Sardine, mackerel and flying fish Squid and mackerel Sardine, pilchard 10
Fishing Gear and Operational Characteristics Pelagic Longline Fishery (Continued) Italy Mediterranean Industrial Swordfish Peru Artisanal Mahi Mahi and Shark South Africa Tuna and Swordfish USA - Hawaii Tuna USA - Hawaii Swordfish June – October Shark season is March – November. Mahi mahi season is December - February. All year All year All year < 60 km 3-4 km 80 km 50 km 60 km Manual Manual Manual Shooter Manual 7-10 days Mahi mahi trips are 5-7 days, shark trips are 15-20 days 10-15 days 21 days 30 days 12-16 Not available 15 12 1 6-9 7-8 (mahi trips) 8-15 10 17 800 - 1400 600 - 2000 1000-1500 2000 800 No No when targeting mahi, yes when targeting sharks No (prohibited) Yes No 20 m 10 m 40 m 35 m 25 m 60 m 16 m 70 m 234 m 69 m 150-300 m 15–30 m 200 m 800 m 500 m 13-18 m 0 m 20 m 22 m 8 m 18 m 10-16 m 20 m 13 m 17 m Nylon monofilament Nylon monofilament Nylon monofilament Nylon monofilament Nylon monofilament 4-8 1 under each buoy 5 27 4 Night Day Afternoon and night Day Night 1 per hook None 1 per hook None (prohibited) 1 every 1-4 hooks None None for mahi mahi; 46.2 g swivels located about 67 cm from the hook used in the shark season 60-80 g 2 m from hook 45-80 g within 1 m of the hook 0 to 80 g 5 to 7 m from hook (midpoint of the branch line) J, Mustad (eye) 0-1 Mustad #2, #3, #4 J hooks 10 degree offset J, size not available Japan tuna 3.6 ring hook, 14/0, 15/0, and 16/0 circle hooks with 10 degree offset 18/0 circle hooks with a 10 degree offset Frozen mackerel Squid, mackerel, flying fish 90% squid, 10% mix of pilchard and mackerel Frozen mackerel, saury, sardine Frozen mackerel, saury, sardine (squid is prohibited) 1 Since 2004 there has been an annual fishery-wide cap of 2,120 sets or until caps on turtle interactions are reached, whichever cap is reached first. In 2006 the fishery reached a cap on loggerhead sea turtles after 3 months. From 1991-2001 vessels targeting swordfish or a combination of swordfish and yellowfin tuna made a mean of 11.8 trips per year 11
Page 3 and 4: Shark Depredation and Unwanted Byca
Page 5: Shark Depredation and Unwanted Byca
Page 9 and 10: Contents Summary and Conclusions 1
Page 11 and 12: Contents Appendix 3. Fiji Pelagic L
Page 13: Contents Appendix 8. USA Hawaii Lon
Page 19 and 20: Chapter 1 Introduction and Methods
Page 21 and 22: Introduction and Methods 1.2. Metho
Page 23: Fishing Gear and Operational Charac
Page 27 and 28: Shark Catch Rates and Disposition T
Page 29 and 30: Chapter 4 National and Internationa
Page 31 and 32: National and International Measures
Page 33 and 34: Economic, Practical, Ecological and
Page 35 and 36: Economic, Practical, Ecological and
Page 37 and 38: Chapter 6 Industry Attitudes and Pr
Page 39 and 40: Industry Attitudes and Practices Lo
Page 41 and 42: Industry Attitudes and Practices Fi
Page 43 and 44: Chapter 7 Potential of Deterrents,
Page 45 and 46: Potential of Deterrents, Hotspot Av
Page 47 and 48: References Campana, S.E., L. Marks,
Page 49: References Neves dos Santos, M., Ga
Page 74 and 75:
Shark Depredation and Unwanted Byca
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 99 and 100:
Appendix 5 Japan Pelagic Longline F
Page 101 and 102:
Japan Pelagic Longline Fisheries Fi
Page 103 and 104:
Japan Pelagic Longline Fisheries mo
Page 105 and 106:
Japan Pelagic Longline Fisheries Ta
Page 107 and 108:
Japan Pelagic Longline Fisheries is
Page 109 and 110:
Japan Pelagic Longline Fisheries ta
Page 111 and 112:
Japan Pelagic Longline Fisheries In
Page 113 and 114:
Japan Pelagic Longline Fisheries A5
Page 115 and 116:
Appendix 6 Peru Artisanal Mahimahi
Page 117 and 118:
Peru Artisanal Mahimahi And Shark L
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Appendix 7 South Africa Pelagic Lon
Page 129 and 130:
South Africa Pelagic Longline Tuna
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Appendix 8 USA Hawaii-based Pelagic
Page 137 and 138:
USA Hawaii-based Pelagic Longline S
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Appendix 9 USA Atlantic, Gulf of Me
Page 149 and 150:
USA Atlantic, Gulf of Mexico and Ca
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
show all

Shark Depredation and Unwanted Bycatch in Pelagic Longline

Create successful ePaper yourself

Delete template?

Save as template?