Shark Depredation and Unwanted Bycatch in Pelagic Longline

More documents

Recommendations

Info

Shark Depredation and Unwanted Bycatch in Pelagic Longline Fisheries the kinkai fleet, 0.175 (sd=0.0339), is higher by a factor of 8. Some of the potential reasons for this higher CPUE in the kinkai fleet have been explored in the previous section. Further information on the operational behavior of the kinkai fleet based on interviews with fishermen is presented in Section A5.5.2. A5.3.4. Species composition of shark catches in longline fleets Prior to 1993, information on shark catches was recorded in logbooks under a single general category (“shark”). Catches recorded in this category were expected to include both pelagic sharks as well as small coastal sharks such as dogfish (Okamoto 2004). A change in logbook recording forms in 1993 (fully implemented as of 1994) provided for separate entries of catches for blue, shortfin mako (Isurus oxyrinchus), porbeagle/salmon sharks (Lamna spp.) and “other” sharks. Information on species composition since 1993 indicates that the majority (≥70%) of the recorded shark catch is blue shark (Fig. A5.7). This fact has led to the development of statistical methods to partition aggregated shark catches prior to 1993 into species-specific catch rate series for the purposes of stock assessment analysis (Nakano and Clarke 2006). The results of these assessments for the sharks shown in Fig. A5.7 are ‘stable’ for blue sharks, ‘possibly in need of conservation or management’ for shortfin mako, and ‘continued monitoring but no current need for management’ for porbeagle/salmon sharks (Suisan Sougou Kenkyuu Center, 2006). In 1997, three other categories of sharks, oceanic whitetip (Carcharhinus longimanus), silky (Carcharhinus falciformis) and threshers (Alopias spp.), were added to the longline logbook format. The time series available for these species is very short but preliminary assessments suggest flat trends in catch per unit effort for silky and thresher sharks and slight declining trends for oceanic whitetip sharks. Global catches by Japanese fleets are estimated in the range of 2-13 mt per year for oceanic whitetips, 0-11 mt for silky sharks and 252-596 mt for thresher sharks (Suisan Sougou Kenkyuu Center 2006). A5.4. Management Framework Relevant to Shark Interactions With regard to enyo and kinkai vessels fishing in international waters, the main applicable management measures for sharks are resolutions or recommendations by regional fisheries management organizations (RFMOs), which discourage finning and encourage full utilization of sharks (Clarke et al. 2006). In addition, some provisions of national finning regulations may indirectly affect operations in international waters. For example, prohibitions on landing shark fins without carcasses in U.S. Pacific territories could, in theory, affect Japanese fishing operations in international waters in the Pacific. Furthermore, any Japanese longline operations in the waters of another country would be required to comply with shark regulations imposed by that country. An example of such regulations would be prohibitions on shark finning in, e.g. South Africa, Brazil, and Costa Rica. In nations where they exist, finning regulations only govern shark utilization and do not limit total catches. Although concerns about overfishing of sharks are widely recognized, catch limits are rare. This is due, in many cases, to the lack of species-specific information necessary to understand the current state of stocks and select desirable fisheries management reference points. In such cases, shark management discussions often default to calls for a general reduction in fishing effort. In this respect, the size of Japan’s enyo and large class kinkai longline fisheries has contracted over time, in part due to actions by government intended to reduce capacity in accordance with the FAO IPOA-Capacity. But due to increasing effort by fleets from other flag states, fishing pressure on pelagic shark stocks is likely to have intensified over time. To support conservation and management of pelagic fishes, Japan contributes data derived from commercial logbooks, as well as results from oceanic research cruises conducted over several decades, to workshops convened by RMFOs and other bodies. Catch and effort trends in Japanese-held databases are summarized annually in published volumes (e.g. Suisan Sougou Kenkyuu Center, 2006). Fig. A5.7. Catch of sharks by species in the tuna longline fishery in the four recording categories used since 1993 (Suisan Sougou Kenkyuu Center 2006). With regard to Japan’s kinkai and engan vessels fishing in national waters, there are no regulatory controls on catch number, effort or utilization, however, enyo, kinkai and some engan vessels are required to record the number of sharks caught in government-submitted logbooks (see preceding section). Recently, a system for monitoring shark resources in national waters was established in accordance with Japan’s National Plan of Action for the Conservation and Management of Sharks (NPOA), prepared in response to the FAO’s International Plan of Action (IPOA)-Sharks. Under this system a committee is tasked with recommending shark conservation and management measures to the Japan Fisheries Agency. Since many fisheries in Japan are controlled by central and prefectural governments through license or approval systems, and entries into fisheries are restricted, fisheries managers believe it is not likely that catch pressures on shark resources in domestic waters will change substantially. Therefore, the current policy holds that there is no recognized need to introduce regulatory measures limiting shark catches in domestic waters (Government of Japan, 2001). In general, the philosophy underpinning the Japan NPOA is one of encouraging fishermen to voluntarily seek solutions to bycatch 92
Japan Pelagic Longline Fisheries issues. This approach is believed to provide the most efficient and ultimately most effective outcome given that bycatch varies according to operational factors which are only thoroughly understood by fishermen themselves. In this regard, Japan encourages full utilization of shark resources, but based on currently available shark CPUE trends, does not actively advocate shark bycatch reduction to fishermen. Given the dearth of catch, effort or utilization regulations applicable to Japanese longline fleets, and the absence of any data on compliance, the economic, social and ecological effects of the various prohibitions on, and policies against, shark finning cannot be rigorously evaluated here. However, some relevant, though anecdotal, information from the interview program is presented in the following sections. A5.5. Shark Handling and Disposition Practices by Fleet Shark handling and final disposition varies with targeting strategy of the vessel, and may also change with season, number of days at sea, recent catch history, and other factors. The following discussion is organized by fleet (enyo, kinkai and engan) but there is some overlap in shark handling and disposition strategies between fleets, as well as important differences within fleets. A5.5.1. Enyo fleet handling and disposition The interviewed enyo fishermen and fishery organization representatives (n=5) explained that in previous decades all shark species, other than shortfin mako sharks, were finned and the carcasses were discarded. Because of the value of their meat shortfin mako carcasses were always retained whole and transported back to Japan. According to the respondents, the other species’ carcasses were not retained because there were no markets for shark meat other than Kesennuma (Japan) and these vessels did not operate out of Kesennuma. In recent years, though, markets for shark meat from all species have developed in some areas. Interview participants listed these areas as including Cape Town (South Africa), Callao (Peru), Las Palmas (Spain), Balboa (Panama), Cartagena (Venezuela) and Port Louis (Mauritius). It was explained that markets do not exist in most other areas, either because of the absence of infrastructure necessary to store shark carcasses in frozen form (-30 o C), or a lack of a local or export market for shark meat. Even where markets do exist, the current price for shark meat is low: large sharks (≥10kg) sell for ≈ 60 cents per kg and small sharks sell for 20 cents per kg. It was stated that these markets existed prior to the implementation of shark finning policies, but it is clear that these low prices are insufficient to motivate retention of the whole shark carcass by tuna fleets, and one source admitted that finning will occur unless otherwise prohibited by law. Therefore, due to finning regulations and other factors, Japanese enyo vessels do offload shark carcasses for sale in some or all of these areas during their frequent port calls. 4 The degree to which enforcement of finning regulations motivates shark meat landing is unknown, but respondents suggested the level of enforcement in South Africa is high, and that landing records are checked in Las Palmas. While shark meat is only beginning to be landed, shark fins have always been utilized at a high rate. Previous information suggested that crew composition and compensation policies (McCoy and Ishihara 1999) can have a strong influence on the number of sharks finned. The interviewed enyo representatives stated that their crew was mainly composed of non-Japanese, mostly Indonesians or sometimes Vietnamese. One respondent agreed that several years ago special bonuses were offered to non-Japanese crew to encourage finning. However, he stated that recently the contracts for Japanese and non-Japanese crew have been standardized. Two other respondents mentioned that profits from finning are split in shares of 50:50 or 33:66 between the company and the crew. There were two types of shark handling practices described in the enyo interviews: • In one case, all hooked sharks are brought on board, the wire leader is wrapped around the shark to pin it, and the vertebrae is cut. If the shark is particularly active, a steel rod is used to destroy the spinal nerves. The fins are always cut and if there is a nearby market for shark meat, the carcass will be headed, gutted and retained. • Other respondents indicated that large sharks (fins of 20-25 cm or longer at the longest edge, or larger than ≈20-30 kg) are stunned with a mallet, if necessary, then the vertebrae is cut and the fins are cut. If there is a nearby market for shark meat the carcass is headed and gutted and any live embryos released; if there is no market the carcass will be discarded. Smaller sharks have the hook pulled out by force and are discarded overboard. Whether these sharks survive depends on where they were hooked and how much damage is done by pulling out the hook, i.e. they are not finned. These fishermen’s perspective was that it was better not to catch sharks and they were pleased if the set contained no sharks. Interview participants stated that even if the rest of the catch is sold in foreign ports, most fins are retained onboard until the return to Japan, but a small percentage of fins may be transshipped at sea or sold in foreign ports. 5 Respondents stated that shark fins will command a higher price if they are dried, therefore prior to finning regulations 95% of vessels would dry fins on deck in a windy, though not necessarily sunny, area. However, in recent years a greater proportion of fins are being frozen to avoid the conspicuous presence of shark fins on deck, which is believed to lead to increased at-sea inspections (particularly in South African waters). 4 In fact, in the three largest foreign landing ports used by the enyo fleet (Callao, Las Palmas and Cape Town), the industry (Japan Tuna) provides support in selling shark meat. The meat is reportedly destined for European markets in Italy and Spain. 5 There is no formal support by the Japanese tuna industry for the selling of shark fins in foreign ports as this business is reported to be tightly controlled by local syndicates. 93
Page 3 and 4:
Shark Depredation and Unwanted Byca
Page 5:
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 16 and 17:
Page 19 and 20:
Chapter 1 Introduction and Methods
Page 21 and 22:
Introduction and Methods 1.2. Metho
Page 23 and 24:
Fishing Gear and Operational Charac
Page 25 and 26:
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 52 and 53:
Page 54 and 55:
Page 56 and 57: Shark Depredation and Unwanted Byca
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: Japan Pelagic Longline Fisheries Ta
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 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
Page 157 and 158:
USA Atlantic, Gulf of Mexico and Ca
Page 159 and 160:
Page 161 and 162:
show all

Shark Depredation and Unwanted Bycatch in Pelagic Longline

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?