Shark Depredation and Unwanted Bycatch in Pelagic Longline
Shark Depredation and Unwanted Bycatch in Pelagic Longline
Shark Depredation and Unwanted Bycatch in Pelagic Longline
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Italy Mediterranean Industrial <strong>Pelagic</strong> Longl<strong>in</strong>e Swordfish Fishery<br />
Di Natale & Pelusi (2000, quoted <strong>in</strong> Commission of the European<br />
Communities, 2003) showed data about shark by-catches of drift<strong>in</strong>g<br />
longl<strong>in</strong>e vessels (Table A4.12).<br />
A4.5.1. Adriatic Sea<br />
Marano et al. (1988) <strong>and</strong> De Zio et al., (2000) present l<strong>and</strong><strong>in</strong>g data at<br />
the port of Monopoli on the South Adriatic Sea, from 1984 to 1987<br />
<strong>and</strong> from 1991 to 1998. Blue shark (Prionace glauca) has the greatest<br />
bycatch rate (Table A4.13).<br />
De Metrio et al. (2000) present data taken onboard drift<strong>in</strong>g longl<strong>in</strong>e<br />
vessels <strong>in</strong> 1998, for the port of Savelletri on the South Adriatic Sea.<br />
Blue sharks (Prionace glauca) still represented the ma<strong>in</strong> by-catch<br />
rate, followed by thresher sharks (Alopias vulp<strong>in</strong>us) (Table A4.14).<br />
A4.5.2. Ionian Sea<br />
De Metrio et al. (1984) present data on blue shark by-catch collected<br />
at l<strong>and</strong><strong>in</strong>g at the port of Porto Cesareo on the North Ionian Sea. The<br />
survey was carried out from 1978 to 1981 (Table A4.15).<br />
Other data are available for the same port (De Metrio et al., 2000). Table<br />
A4.16a presents statistics about blue shark (Prionace glauca) bycatches<br />
observed on vessels target<strong>in</strong>g swordfish <strong>and</strong> albacore <strong>in</strong> 1998. Table<br />
A4.16b presents statistics on blue sharks l<strong>and</strong>ed at Porto Cesareo <strong>in</strong><br />
1998. A complete shark by-catch report cover<strong>in</strong>g 1978-1985 is given<br />
by Filanti et al. (1986) for longl<strong>in</strong>es target<strong>in</strong>g swordfish (Table A4.17).<br />
Data were collected by on-board observers.<br />
A4.5.3. Ligurian Sea<br />
Garibaldi & Orsi Rel<strong>in</strong>i (2000) present data for the Cetacean<br />
Sanctuary of the Ligurian Sea. In the years 1990-1998 the small<br />
longl<strong>in</strong>e fish<strong>in</strong>g fleet of Sanremo (3-7 vessels target<strong>in</strong>g swordfish)<br />
by-caught Prionace glauca, Alopias vulp<strong>in</strong>us, Isurus oxyr<strong>in</strong>chus,<br />
Carchar<strong>in</strong>us plumbeus <strong>and</strong> Lamna nasus. The Blue shark was the<br />
ma<strong>in</strong> by-catch (Table A4.18). The overall ratio swordfish/blue shark<br />
catches was 18,5/1 <strong>in</strong> number.<br />
Other data are available from swordfish longl<strong>in</strong>e vessels for the ports<br />
of Imperia <strong>and</strong> Sanremo (Orsi Rel<strong>in</strong>i et al., 1999). The survey was<br />
carried out at l<strong>and</strong><strong>in</strong>g (Table A4.19). Prionace glauca forms 95% of<br />
number caught, the rema<strong>in</strong><strong>in</strong>g is composed of Alopias vulp<strong>in</strong>us, Isurus<br />
oxyrh<strong>in</strong>chus, Lamna nasus <strong>and</strong> Carcharh<strong>in</strong>us plumbeus.<br />
A4.5.4. Tyrrhenian Sea <strong>and</strong> Strait of Sicily<br />
Di Natale (1998) reported the CPUE <strong>in</strong> number of specimen/km of<br />
swordfish longl<strong>in</strong>e gear of three by-catch species: Prionace glauca =<br />
0.358; Isurus oxyrh<strong>in</strong>chus = 0.051; Sphyrna zygaena = 0.026. Data<br />
were collected by on board observers <strong>in</strong> 1994-1995. He also shows<br />
data from port l<strong>and</strong><strong>in</strong>gs (Table A4.20).<br />
Table A4.8. Italian fish<strong>in</strong>g fleet: catches of smooth-hounds (Mustelus spp.) <strong>in</strong> the Mediterranean sea dur<strong>in</strong>g 1995-2004 (FAO Fishstat Plus - GFCM Capture<br />
Production 1970-2004).<br />
Year 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004<br />
tons 5,942 2,659 621 636 440 462 369 325 423 483<br />
Table A4.9. Catches: percentage composition of species by fish<strong>in</strong>g gear <strong>in</strong> the large pelagic longl<strong>in</strong>e fisheries of the Mediterranean Sea, 1998-1999<br />
(Megalofonou et al., 2005).<br />
% species at l<strong>and</strong><strong>in</strong>g sites % species on board % species all<br />
SWO ALB BFT SWO ALB BFT SWO ALB BFT<br />
<strong>Shark</strong>s 19.01 0.37 — 9.64 0.26 2.10 17.67 0.32 2.10<br />
Swordfish 75.46 30.47 — 67.77 5.07 1.36 74.37 17.97 1.36<br />
Northern<br />
bluef<strong>in</strong> tuna<br />
2.39 4.21 — 2.44 13.00 94.99 2.40 8.54 94.99<br />
Albacore 0.07 60.95 — 0.05 76.32 0.00 0.07 68.52 0.00<br />
Other 3.07 3.99 — 20.10 5.35 1.56 5.51 4.66 1.56<br />
SWO = swordfish longl<strong>in</strong>e, ALB = albacore longl<strong>in</strong>e, BFT = Northern bluef<strong>in</strong> tuna longl<strong>in</strong>e<br />
Table A4.10. Fish<strong>in</strong>g sets, effort (x1000 hooks or 1000 m of net) <strong>and</strong> catch rates (number of fish/1000 hooks) of sharks <strong>and</strong> target species <strong>in</strong> the swordfish<br />
longl<strong>in</strong>e fisheries of the Mediterranean Sea, 1998-1999 (Megalofonou et al., 2005).<br />
Area Sets Effort Prionace glauca<br />
CPUE<br />
Alopias vulp<strong>in</strong>us<br />
CPUE<br />
Galeorh<strong>in</strong>us galeus<br />
CPUE<br />
Other sharks<br />
CPUE<br />
SWO<br />
CPUE<br />
Ionian 140 267.4 0.759 0.000 0.000 0.004 3.152<br />
Adriatic 69 166.3 1.678 0.048 0.000 0.000 3.879<br />
Tyrrhenian 9 18.5 0.270 0.000 0.000 0.000 8.428<br />
Strait of Sicily 23 46.4 0.065 0.022 0.022 0.108 14.526<br />
79