Shark Depredation and Unwanted Bycatch in Pelagic Longline

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Shark Depredation and Unwanted Bycatch in Pelagic Longline Fisheries Table A6.1. Landings in metric tons from the elasmobranch fishery in Peru from 1990-1999 (in Cattarci, 2004). Species 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 Rays 4311 2081 2771 3632 1658 1841 1126 1177 1477 1790 Smoothounds 6458 2705 8578 8747 3431 4125 3230 3166 8038 448 Sharks 768 525 2087 1212 548 694 1506 1915 4335 2043 Total 11537 5311 13436 13591 5637 6660 5862 6258 13850 18131 A6.2. Artisanal Longline Fleet Characteristics Longline fishing was reintroduced in Peru in the late 1980s (Reyes, 1989) due in part to the collapse of traditional fisheries for boney fish (Bonfil, 1996; Cattarci, 2004) and the search for new fishing techniques. By the 1990s this fishing method had expanded, especially in Peru’s southern ports (Escudero, 1997; Castejon pers comm.). During the past decade the longline fishery has increased significantly. The main target species are mahi mahi Coryphaena hippurus during the austral summer and sharks, especially blue sharks Prionace glauca, mako sharks Isurus oxyrinchus and hammerhead sharks Sphyrna zygaena, from autumn to spring. Artisanal fisheries are defined according to Peruvian fisheries regulations as containing boats with a maximum of 32.6 m3 of storage capacity, 15 m in length, and principally based on the use of manual work during fishing operations (Ley General de Pesca, 2001). By the 1990’s there were an estimated 190 longline vessels in Peru (Jahncke et al., 2001). More recent information estimated that approximately 1500 longline vessels operate during the mahi mahi season (IMARPE, unpublished data). Peru’s artisanal fleet is very large and diverse. Artisanal fisheries contain mainly wooden vessels. A 1997 study of the fishery indicated that there were more than 28,000 fishermen and 6,200 vessels operating out of 109 ports (Escudero, 1997). One of the main fishing methods employed is longlines. Statistics from IMARPE indicate that 1,968 longline trips were recorded for the second half of the year 1999 (Estrella et al., 2000). More recent information on artisanal longlines indicates that in 2002, 11,316 trips were conducted (IMARPE, unpublished data). This suggests substantial growth in the longline fishery since 1999. While there is much variation in longline fishing methods throughout the country, some general characterizations can be made (Fig. A6.2, Table A6.2). Longline vessels typically set their gear in the morning and recover it in the early evening. Gear is set at the surface. Mainline length varies by boat and number of hooks but is typically about 3-4 km. in length (See Fig. A6.2). The main target species include Fig. A6.2. Typical gear design of a Peruvian pelagic longline. sharks and mahi mahi. Sharks are fished from approximately March to November and mahi mahi are fished from December to February. Trip length varies by season with mahi mahi trips typically lasting 5-7 days and shark trips lasting 15-20 days. Vessels may travel up to 250 miles from shore. Hook size and type varies but almost all vessels use J hooks. Northern ports tend to use smaller hooks than in the south. Species used for bait include giant squid, mackerel, and flying fish. Bait may be fresh, frozen or salted. Weighted branchlines are used in some ports, and are used more often in the south of the country. Steel leaders are often used during shark season to reduce gear loss. There are very few restrictions on the operation of artisanal vessels. There are no quotas on the number of vessels, number of vessels per owner, or on the longline gear itself. Monitoring of landings is conducted by the Ministry of Fisheries and by IMARPE. Monitoring is done in terms of metric tons of specimens landed. Only the commercial species are monitored. Vessel departure permits and security controls are managed by the Peruvian Navy - Direccion de Capitanias y Puertos (DICAPI). A6.3. Range of Fishing Gear and Methods Table A6.3 summarizes the general fishing methods and gear deployment strategies for the longline fleet in the ports where surveys were conducted - Paita, Salaverry and Ilo. It should be noted, however, that fishing methods and gear deployment vary somewhat from port to port and vessel to vessel. 102
Peru Artisanal Mahimahi And Shark Longline Fishery Table A6.2 Characteristics of the mahi mahi and shark seasons of the Peru longline fishery. Seasonal Target Species Gear Characteristic Mahi Mahi Sharks Hook Type J#2 J#0, 1/0 # Hooks 600-1500 800-2000 Trip Length Up to 6 days Up to 20 days Sets/Day 1-2 1 Distance 20-70 nm 250-500 nm Bait Flying fish, squid, mackerel Flying fish, squid, mackerel, cetaceans Season December - March April – November Target Species Mahi mahi Mako & Blue shark Table A6.3. Fishing gear deployment of the Peruvian artisanal mahi mahi longline fishery (Mangel and Alfaro-Shigueto, 2003 and data from interviews conducted in this study). Mainline material Mainline length Mainline deployment Distance between buoys Distance from buoy to mainline (float line length) Average branch line length Branch line material ‘Papelillo’ (blue multifilament nylon rope) Average of 3 kilometers Manual 27 m (15 fathoms) ~0.15 m 9 to 10 m Nylon monofilament/cable Wire trace or leader on branch lines Number of hooks between buoys 1 to 2 Some use, but typically during shark season or at the transition between shark and mahi mahi season (1 m length) Average maximum depth of hooks when set Average maximum depth of mainline when set Mainline sink rate Timing of set, soak, and haul Lightstick use 18 m (87% fishermen say set at 10bz or less) Surface No information available Gear is set in the early morning, soaks during the day, and is hauled before dark. No Number of hooks per set average 700 for mahi mahi season (range: 600-1500) Hook setting interval Radio beacons Hook type Weight size and location No information available No Mustad #2, #3, #4 J hooks 10 degree offset No weighted swivels used for mahi mahi 46.2 g swivels, located ~67cm from hook for sharks Clip size and type Bait type Number of crew Vessel Monitoring System Not typically used Mackerel, flying fish, squid Captain and 3 crew No 103
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Shark Depredation and Unwanted Byca
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Contents Summary and Conclusions 1
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Contents Appendix 3. Fiji Pelagic L
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Contents Appendix 8. USA Hawaii Lon
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Chapter 1 Introduction and Methods
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Introduction and Methods 1.2. Metho
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Fishing Gear and Operational Charac
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Fishing Gear and Operational Charac
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Shark Catch Rates and Disposition T
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Chapter 4 National and Internationa
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National and International Measures
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Economic, Practical, Ecological and
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Economic, Practical, Ecological and
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Chapter 6 Industry Attitudes and Pr
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Industry Attitudes and Practices Lo
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Industry Attitudes and Practices Fi
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Chapter 7 Potential of Deterrents,
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Potential of Deterrents, Hotspot Av
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References Campana, S.E., L. Marks,
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References Neves dos Santos, M., Ga
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Page 99 and 100: Appendix 5 Japan Pelagic Longline F
Page 101 and 102: Japan Pelagic Longline Fisheries Fi
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Page 113 and 114: Japan Pelagic Longline Fisheries A5
Page 115: Appendix 6 Peru Artisanal Mahimahi
Page 119 and 120: Peru Artisanal Mahimahi And Shark L
Page 127 and 128: Appendix 7 South Africa Pelagic Lon
Page 129 and 130: South Africa Pelagic Longline Tuna
Page 135 and 136: Appendix 8 USA Hawaii-based Pelagic
Page 137 and 138: USA Hawaii-based Pelagic Longline S
Page 147 and 148: Appendix 9 USA Atlantic, Gulf of Me
Page 149 and 150: USA Atlantic, Gulf of Mexico and Ca
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Shark Depredation and Unwanted Bycatch in Pelagic Longline

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