Shark Depredation and Unwanted Bycatch in Pelagic Longline

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Shark Depredation and Unwanted Bycatch in Pelagic Longline Fisheries U.S. National Marine Fisheries Service. 2002. Fisheries off West Coast States and in the Western Pacific; Atlantic Highly Migratory Species; Fisheries of the Northeastern United States; Implementation of the Shark Finning Prohibition Act. Federal Register 67(28): 6194-6202. U.S. National Marine Fisheries Service. 2001. Endangered Species Act Section 7 Consultation Biological Opinion: Authorization of Pelagic Fisheries under the Fishery Management Plan for the Pelagic Fisheries of the Western Pacific Region. Watson, J., Foster, D., Epperly, S., Shah, A. 2005. Fishing methods to reduce sea turtle mortality associated with pelagic longlines. Canadian Journal of Fisheries and Aquatic Sciences 62. Western Pacific Regional Fishery Management Council. 2005a. Pelagic Fisheries of the Western Pacific Region. 2004 Annual Report. Honolulu, HI, USA. Western Pacific Regional Fishery Management Council. 2005b. Fishery Ecosystem Plan for Pacific Pelagic Fisheries of the Western Pacific Region. Western Pacific Regional Fishery Management Council, Honolulu, HI, USA, 215 pp. Western Pacific Regional Fishery Management Council. 2003. Managing Marine Fisheries of the U.S. Pacific Islands. Past, Present, and Future. Prepared by E. Gilman, ELG Environmental Services. WPFMC, Honolulu, HI, USA. 25 pp. Western Pacific Fishery Management Council. 132
Appendix 9 USA Atlantic, Gulf of Mexico and Caribbean Pelagic Longline Swordfish and Tuna Fisheries: Industry Practices and Attitudes towards Shark Depredation and Unwanted Bycatch John W. Mandelman and Tim B. Werner, New England Aquarium, jmandelman@neaq.org, twerner@neaq.org A9.1. Introduction It is widely held that the incidental capture of sharks in fisheries targeting alternative species represents a massive challenge in the proper management of this group (Figs. A9.1 and A9.2) (Barker and Schluessel, 2004). Akin to the outcome in high-seas commercial fisheries around the globe, sharks compose the highest percentage of bycatch in the U.S. Atlantic PLL (PLL) fishery for swordfish, tunas and tuna-like species (Beerkircher et al., 2002). Although rarely targeted in U.S. domestic PLL operations, sharks and rays constituted 25% of the overall catch in this fishery between 1992 and 2003 according to observer data (Abercrombie et al., 2005). If accounting for the other foreign fleets pelagic longlining in Atlantic waters, it has been estimated that the extent of shark bycatch by this capture method is considerably high, rivaling both the Indian and Pacific in terms of the number of individuals and overall shark biomass taken (Bonfil, 1994). Sharks are also among those responsible for inflicting damage (depredation) to baits, gear, and hooked targeted catch prior to haul-back in this fishery (Hoey and Moore, 1999). The species most commonly encountered in PLL operations are a variety of carcharhinids, and to a lesser extent, lamnid sharks. As several of these species are either prohibited from being landed or lack appreciable commercial value, discard rates are chronically high. For these reasons, interactions with sharks in the domestic PLL fishery are presumed as a relative nuisance; encumbering commercial operations for tuna and swordfish and afflicting fishermen with considerable costs through losses of and damage to gear, target catch (via depredation) and time. At the same time, physiological stress and physical trauma imposed during capture and handling can compromise the ultimate survival of discarded shark bycatch (Bonfil, 1994; Berkeley and Campos, 1988). If coupled with directed landings, discard mortality can elevate total fishing mortality (F) and imperil shark populations around the globe (Musick et al., 2000). The control of unintended shark Fig. A9.1. Longline captured Isursus oxyrinchus (shortfin mako shark), just prior to boarding. (Photo courtesy of Greg Skomal, Massachusets Division of Marine Fisheries, USA.) Fig. A9.2. Longline captured Prionance glauca (blue shark), just after boarding. (Photo courtesy of Greg Skomal, Massachusets Division of Marine Fisheries, USA.) interactions is thus important not only for the operations of the longline fishing industry, but the health of interacting shark populations. Importantly, bycatch issues have been the basis of several regulatory measures imposed upon the Atlantic PLL fleet. It is therefore clear that mitigating the extent of incidental takes in this fishery, inclu-ding those with sharks, will behoove industry, management and conservation communities alike. In the following report, we address the estimated extent of shark bycatch, the species composition of this catch, and to a much lesser extent, shark depredation in the PLL fishery of the Atlantic, Caribbean and Gulf of Mexico (GOM). We also present ongoing research and potential strategies regarding the attenuation of shark interactions in this fishery. In doing so, several important factors regarding the data sources must first be addressed. 133
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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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Shark Depredation and Unwanted Bycatch in Pelagic Longline

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