Shark Depredation and Unwanted Bycatch in Pelagic Longline

More documents

Recommendations

Info

Shark Depredation and Unwanted Bycatch in Pelagic Longline Fisheries Table A4.5. Italian fishing fleet: catches of sharks in 2004 (IREPA, 2006). Catch (t) Revenue (mln) Price /kg Sharks 951 4.66 4.90 Total fish 201,230 814.42 4.05 Table A4.6. Italian fleet: shark catches, revenue and price, 2004 (IREPA, 2006). Catches (t) Revenue (mln) Price /kg Trawlers 308 1.73 5.64 Small scale 517 2.58 4.98 Longliners 50 0.09 1.88 Total 951 4.66 4.90 Table A4.7. Small-scale and large-scale pelagic and demersal longline Italian fleet: catches of sharks and target species, 2004 (IREPA, 2006). Catch (t) Revenue (million) Price/kg Sharks 50 0.09 1.88 Swordfish – Xiphias gladius 3,884 46.98 12.10 Northern bluefin tuna – Thunnus thynnus 319 2.28 7.13 Albacore – Thunnus alalunga 1,115 4.32 3.88 Total fish 8,782 79.17 9.02 There is no Italian longline fishery that targets sharks. Traditional fishing activities with demersal longline targeting chondrichthyans, such as bluntnose sixgill shark (Hexanchus griseus) fishing in the Ionian Sea and kitefin shark (Dalatias licha) fishing in the Ligurian Sea, have long been abandoned (Vacchi & Notarbartolo di Sciara, 2000). Shark finning does not occur on Italian vessels (Orsi Relini, 2000). In any case, Council Regulation (EC) 1185/2003 provides that removing shark fins on board, retaining and sell them is prohibited. Sharks are captured mainly by trawlers (32.4%) and small scale fishing practices (54.4%), or as by-catch of longliners (5.3%) (Table A4.6) (IREPA, 2006). Official data and statistics on shark catches and by-catches suffer from the same, already mentioned problem: no data are available for drifting longline only, because drifting and set gears are included in the same class (Table A4.7), which also includes small- and large-scale fisheries. Moreover, official trend data on shark catches are of limited utility and difficult to interpret because many species of small and medium sized sharks are generically recorded as “palombo” (Mustelus spp.) (De Metrio et al., 1982b; Vacchi & Notarbartolo di Sciara, 2000) and so reported to international bodies (Table A4.8). According to Vannuccini (1999), the main shark species caught by the Italian fleet as by-catch are blue sharks (Prionace glauca),thresher (Alopias vulpinus) and porbeagle (Lamna nasus). Di Natale (1998) enclosed a list of shark species reported in the by-catch of the Italian longline large pelagic fishery: Alopias vulpinus, Alopias superciliosus, Carcharhinus brevipinna, Carcharhinus limbatus, Carcharhinus obscurus, Carcharhinus plumbeus, Prionace glaca, Cetorhynus maximus, Heptranchias perlo, Hexanchus griseus, Carcharodon carcharias, Isurus oxyrinchus, Lamna nasus, Eugomphodus taurus, Odontaspis ferox, Sphyrna zygaena, Sphyrna mokarran, Sphyrna sp., Squalus acanthias, Squalus blainvillei, Galeorhinus galeus, Mustelus mustelus. The same author (Di Natale, 1998) also reported that some shark species, such as Alopias ssp., Isurus oxyrhinchus, Lamna nasus, are usually marketed, while other species are sometimes marketed (Prionace glauca, Carcharhinus ssp., Carcharodon carcharias, Squalus ssp., Heptranchias perlo, Hexanchus griseus, Mustelus ssp., Sphyrna ssp.). Guglielmi et al. (2000) reported that Prionace glauca is marketed only by some fisheries (mainly on Adriatic Sea coast), while other species (Isurus oxyrhinchus and Lamna nasus) are valuable and usually marketed. De Metrio et al. (1982a), in a paper related to blue shark dynamics of fishing in the Salento area (North Ionian Sea), reported a trade of this species, with more then 1,000 specimen totally landed in 1979-1980. Quantitative data about drifting longline shark by-catch are available from a few papers. We subdivide bibliographic material according to the seas where the studies were carried on. Unfortunately, these papers usually do not provide separate data for small-scale and largescale longline fisheries. A4.5. Mediterranean Sea Megalofonou et al. (2005) conducted a study of incidental catches and discards of pelagic sharks from the swordfish and tuna fisheries in the Mediterranean Sea. Data were taken onboard and at fishing ports from 1998 to 2000 (Table A4.9). Sharks comprise about 18% of the total catch of the Italy Mediterranean Sea large pelagic longline fishery. Blue shark (Prionace glauca) was the main by-catch species in all gears and areas examined. The next most abundant species were shortfin mako (Isurus oxyrinchus), thresher shark (Alopias vulpinus), and tope shark (Galeorhinus galeus) (Megalofonou et al., 2005). Table A4.10 shows data related to Italian waters recorded onboard during a study by Megalofonou et al. (2005), where the average shark combined species CPUE of the four fishing areas was 0.744 sharks combined species per 1000 hooks. Guglielmi et al. (2000) present data from onboard observations during fishing seasons 1998-1999. Sharks were caught by swordfish, albacore and Northern bluefin tuna longline vessels in the Central Mediterranean Sea (Table A4.11). 78
Italy Mediterranean Industrial Pelagic Longline Swordfish Fishery Di Natale & Pelusi (2000, quoted in Commission of the European Communities, 2003) showed data about shark by-catches of drifting longline vessels (Table A4.12). A4.5.1. Adriatic Sea Marano et al. (1988) and De Zio et al., (2000) present landing data at the port of Monopoli on the South Adriatic Sea, from 1984 to 1987 and from 1991 to 1998. Blue shark (Prionace glauca) has the greatest bycatch rate (Table A4.13). De Metrio et al. (2000) present data taken onboard drifting longline vessels in 1998, for the port of Savelletri on the South Adriatic Sea. Blue sharks (Prionace glauca) still represented the main by-catch rate, followed by thresher sharks (Alopias vulpinus) (Table A4.14). A4.5.2. Ionian Sea De Metrio et al. (1984) present data on blue shark by-catch collected at landing at the port of Porto Cesareo on the North Ionian Sea. The survey was carried out from 1978 to 1981 (Table A4.15). Other data are available for the same port (De Metrio et al., 2000). Table A4.16a presents statistics about blue shark (Prionace glauca) bycatches observed on vessels targeting swordfish and albacore in 1998. Table A4.16b presents statistics on blue sharks landed at Porto Cesareo in 1998. A complete shark by-catch report covering 1978-1985 is given by Filanti et al. (1986) for longlines targeting swordfish (Table A4.17). Data were collected by on-board observers. A4.5.3. Ligurian Sea Garibaldi & Orsi Relini (2000) present data for the Cetacean Sanctuary of the Ligurian Sea. In the years 1990-1998 the small longline fishing fleet of Sanremo (3-7 vessels targeting swordfish) by-caught Prionace glauca, Alopias vulpinus, Isurus oxyrinchus, Carcharinus plumbeus and Lamna nasus. The Blue shark was the main by-catch (Table A4.18). The overall ratio swordfish/blue shark catches was 18,5/1 in number. Other data are available from swordfish longline vessels for the ports of Imperia and Sanremo (Orsi Relini et al., 1999). The survey was carried out at landing (Table A4.19). Prionace glauca forms 95% of number caught, the remaining is composed of Alopias vulpinus, Isurus oxyrhinchus, Lamna nasus and Carcharhinus plumbeus. A4.5.4. Tyrrhenian Sea and Strait of Sicily Di Natale (1998) reported the CPUE in number of specimen/km of swordfish longline gear of three by-catch species: Prionace glauca = 0.358; Isurus oxyrhinchus = 0.051; Sphyrna zygaena = 0.026. Data were collected by on board observers in 1994-1995. He also shows data from port landings (Table A4.20). Table A4.8. Italian fishing fleet: catches of smooth-hounds (Mustelus spp.) in the Mediterranean sea during 1995-2004 (FAO Fishstat Plus - GFCM Capture Production 1970-2004). Year 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 tons 5,942 2,659 621 636 440 462 369 325 423 483 Table A4.9. Catches: percentage composition of species by fishing gear in the large pelagic longline fisheries of the Mediterranean Sea, 1998-1999 (Megalofonou et al., 2005). % species at landing sites % species on board % species all SWO ALB BFT SWO ALB BFT SWO ALB BFT Sharks 19.01 0.37 — 9.64 0.26 2.10 17.67 0.32 2.10 Swordfish 75.46 30.47 — 67.77 5.07 1.36 74.37 17.97 1.36 Northern bluefin tuna 2.39 4.21 — 2.44 13.00 94.99 2.40 8.54 94.99 Albacore 0.07 60.95 — 0.05 76.32 0.00 0.07 68.52 0.00 Other 3.07 3.99 — 20.10 5.35 1.56 5.51 4.66 1.56 SWO = swordfish longline, ALB = albacore longline, BFT = Northern bluefin tuna longline Table A4.10. Fishing sets, effort (x1000 hooks or 1000 m of net) and catch rates (number of fish/1000 hooks) of sharks and target species in the swordfish longline fisheries of the Mediterranean Sea, 1998-1999 (Megalofonou et al., 2005). Area Sets Effort Prionace glauca CPUE Alopias vulpinus CPUE Galeorhinus galeus CPUE Other sharks CPUE SWO CPUE Ionian 140 267.4 0.759 0.000 0.000 0.004 3.152 Adriatic 69 166.3 1.678 0.048 0.000 0.000 3.879 Tyrrhenian 9 18.5 0.270 0.000 0.000 0.000 8.428 Strait of Sicily 23 46.4 0.065 0.022 0.022 0.108 14.526 79
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: 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 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 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 143 and 144:
USA Hawaii-based Pelagic Longline S
Page 145 and 146:
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 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

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

Delete template?

Save as template?