A.1 SUMMARY OF DISCARD ESTIMATE WITH CONFIDENCE LIMITS
TABLE 14
Summary of discard estimate with confidence
limits
Sum of landings (discard database) (tonnes) |
78 432 299 |
|
Sum of discards (discard database) (tonnes) |
6 824 186 |
|
Weighted mean of discard rates (weighted discard rate) |
8.00% |
|
Arithmetic mean of discard rates |
14.59% |
|
Fishstat ten-year average marine nominal catch 1992-2001 (tonnes) |
83 805 355 |
|
Discard database landings as percentage of Fishstat ten-year average nominal catch |
94% |
|
Variance of discard rates (weighted mean)1 |
0.057 |
|
Standard deviation (using the weighted mean) |
0.238 |
|
Standard error of weighted mean |
0.011 |
|
Confidence (95%) R - |
- 0.059 |
|
Confidence (95%) R + |
+ 0.101 |
|
Correlation coefficient |
13.31 |
|
Range of total estimated discards (discard database): |
|
|
|
Lower |
6 420 441 |
|
Upper |
7 512 897 |
Range for discard rate: |
|
|
|
Lower |
7.57% |
|
Upper |
8.74% |
Range of discard rates applied to Fishstat ten-year average global catch: |
|
|
|
Lower |
6 860 277 |
|
Upper |
8 027 573 |
1 Standard deviation and confidence limits have been calculated with reference to the weighted mean. The variance refers to that of discard rates in the discard database and does not reflect the internal variance of individual records.
Source: discard database.
A.2 DETAILS OF DISCARDS BY TYPE OF FISHERY
A.2.1 Trawl fisheries
TABLE 15
Shrimp trawl fisheries with highest discards
(tonnes)
Country |
Fishery |
Period |
Landings |
Discard |
Discards |
|
Tropical shrimp fisheries |
||||||
|
United States |
Gulf of Mexico shrimp |
2000 |
116 408 |
56.9 |
480 183 |
|
Indonesia |
Arafura Sea shrimp trawl |
1998 |
53 786 |
81.7 |
239 594 |
|
Ecuador |
Ecuador industrial shrimp |
1996 |
24 113 |
79.1 |
91 211 |
|
Venezuela |
East and west industrial shrimp trawl |
1997 |
50 423 |
60.0 |
75 634 |
|
United States |
South Atlantic Shrimp |
2000 |
14 646 |
83.3 |
73 230 |
Coldwater shrimp fisheries |
||||||
|
Peru |
Industrial shrimp trawl |
2000 |
17 405 |
81.0 |
74 200 |
|
Argentina |
Red shrimp tangoneros trawl |
2000 |
36 823 |
50.1 |
37 000 |
|
Portugal |
Algarve Nephrops and deepwater shrimp |
1996 |
5 543 |
70.0 |
35 000 |
|
Japan |
Small sail trawl |
1994 |
388 |
95.7 |
8 691 |
|
Norway |
Shrimp trawl in Nordsjøen/Skagerakk |
Annual |
6 000 |
51.2 |
6 300 |
Note: in addition the United Kingdom (Area 27) Nephrops fisheries have discards in the order of 30 000 tonnes.
TABLE 16
Non-shrimp trawl fisheries with highest
discards (tonnes) and discard rates
Country |
Fishery |
Period |
Landings |
Discard |
Discards |
|
Fisheries with highest discards |
||||||
|
All fleets |
North Sea beam trawl (sole flatfish directed) |
Average |
148 261 |
69.0 |
330 000 |
|
Japan |
Small otter and beam trawl powered, other |
1994 |
166 584 |
60.5 |
254 874 |
|
Argentina |
Hake otter trawl south of 41oS |
1997 |
468 664 |
24.0 |
147 999 |
|
United States |
Washington, Oregon, California multispecies |
2002 |
165 730 |
44.0 |
130 216 |
|
Morocco |
Industrial otter trawl demersal for |
Recent |
96 771 |
30.0 |
95 565 |
Fisheries with highest discard rates |
||||||
|
France |
Deepwater trawl western waters |
1996 |
13 352 |
90.0 |
11 921 |
|
Portugal |
Tagus estuary beam trawl for flatfish |
|
1 750 |
90.0 |
|
|
Bangladesh |
Industrial finfish trawl for Saurida, |
Average |
7 140 |
83.0 |
34 860 |
|
Belgium |
Flatfish beam trawl |
1999 |
23 000 |
75.0 |
69 000 |
|
Brunei Darussalam |
Multispecies finfish and penaeid trawl |
1998 |
1 214 |
74.2 |
3 579 |
|
United States |
GOA catcher processor trawl |
2001 |
7 621 |
69.1 |
5 268 |
TABLE 17
Selected demersal otter trawl fisheries with
high discards (tonnes)
Country |
Fishery |
Period |
Landings |
Discard rate (%) |
Discards |
Morocco |
Foreign demersal multispecies1 |
Recent average |
146 746 |
30.0 |
106 308 |
Morocco |
Industrial demersal for cephalopods, sparids and hake2 |
Recent average |
96 771 |
30.0 |
95 565 |
France |
Offshore multispecies demersal trawl for finfish and Nephrops |
Recent average |
162 484 |
28.1 |
63 502 |
Japan |
Offshore trawl for walleye pollock, greenling and squid |
1994 |
442 412 |
12.3 |
61 938 |
Bangladesh |
Industrial finfish trawl for Saurida, Upeneus and Sepia |
Average |
7 140 |
83.0 |
34 860 |
1 Fishery now largely ceased. 2 Moroccan flag.
TABLE 18
Midwater (pelagic) trawl fisheries with highest
discards (tonnes)
Country |
Fishery |
Period |
Landings |
Discard rate (%) |
Discards |
Morocco |
Foreign Atlantic sardine, mackerel, horse mackerel |
Recent average |
724 680 |
2.5 |
35 982 |
Ireland |
Mackerel, horse mackerel, blue whiting |
2001 |
155 450 |
11.0 |
19 213 |
Netherlands |
Horse mackerel |
1994 |
110 000 |
11.8 |
14 717 |
France |
Sardine and tuna |
Recent average |
22 637 |
37.7 |
13 698 |
France |
Celtic Sea and Biscay |
Recent average |
35 506 |
26.3 |
12 671 |
TABLE 19
Selected trawl fisheries with high discards
(tonnes)
Country |
Fishery |
Period |
Landings |
Discard rate (%) |
Discards |
Belgium |
Flatfish (plaice, sole) beam trawl |
1999 |
23 000 |
75.0 |
69 000 |
Japan |
East China Sea distant water cephalopod trawl |
1994 |
45 420 |
38.2 |
28 070 |
South Africa |
Hake trawl |
1996 |
258 509 |
14.0 |
31 951 |
Chile |
Industrial hake trawl (Regions V to X) |
2000 |
176 033 |
12.5 |
25 148 |
Argentina |
Coastal iced fish hake trawl (costera) |
2000 |
100 000 |
13.0 |
15 000 |
Peru |
Industrial merluza trawl |
2000 |
83 361 |
15.0 |
14 711 |
United States |
BSAI catcher processor yellowfin sole trawl |
2001 |
99 173 |
29.9 |
29 667 |
United States |
BSAI catcher processor flathead sole trawl |
2001 |
30 196 |
40.6 |
12 270 |
These tables may show apparent inconsistencies. These are generally due to the fact that one or more of the values (landing, discard quantities or discard rate) may be derived from different sources, e.g. one report may provide only a discard rate, while the quantity of discards may be derived from a different source.
A.2.2 Other types of fisheries
TABLE 20
Discard rates and discards in other
fisheries
Fishery |
Discard rate for set of all records with a discard rate |
Discard rate and discards for set of complete records1 |
||||
Average discard rate (%) |
No. records |
Standard deviation |
Landings (tonnes) |
Discards (tonnes) |
Weighted discard rate (%)1 |
|
Midwater trawl fisheries |
||||||
Tuna midwater trawl |
|
4 |
|
62 050 |
26 532 |
30.0 |
Small pelagics midwater trawl |
5.7 |
19 |
0.07 |
2 763 040 |
101 285 |
3.5 |
Net fisheries (other) |
|
|
|
|
|
|
Tuna purse seine |
4.85 |
12 |
0.02 |
2 673 378 |
144 152 |
5.1 |
Small pelagics seine |
2.0 |
52 |
0.03 |
21 664 338 |
351 111 |
1.6 |
Beach seine |
31.9 |
6 |
0.27 |
23 061 |
1 068 |
4.4 |
Gillnet |
7.2 |
48 |
0.12 |
3 350 299 |
29 004 |
0.5 |
Line fisheries |
||||||
Tuna pole and line |
0.1 |
11 |
0.003 |
818 505 |
3 121 |
0.4 |
Tuna longline |
22.0 |
37 |
0.16 |
1 403 591 |
560 481 |
29 |
Non-tuna line fisheries |
8.5 |
50 |
0.12 |
581 560 |
47 257 |
7.5 |
Bottom longline (all) |
8.2 |
20 |
0.08 |
209 927 |
10 988 |
7.5 |
Handline |
1.8 |
16 |
0.02 |
155 211 |
3 149 |
2.0 |
Squid jig |
0.2 |
9 |
0.004 |
1 134 432 |
1 671 |
0.1 |
Finfish jig |
1.1 |
5 |
0.021 |
19 296 |
710 |
3.5 |
Dredge, pot and other fisheries |
||||||
Dredge (scallop, clam, whelk) |
24.8 |
10 |
0.17 |
165 660 |
65 373 |
28 |
Hand collection |
0.8 |
16 |
0.02 |
256 879 |
899 |
0.3 |
Crustacean pots (lobster, crab) |
12.4 |
12 |
0.14 |
185 547 |
71 077 |
27.7 |
Multigear and/or multispecies2 |
2.4 |
109 |
0.07 |
6 023 146 |
85 436 |
1.4 |
1 Records with landings, discards and discard rate. 2Non-trawl fisheries.
TABLE 21
Discard rates and discards in gillnet
fisheries
Country |
Fishery |
Period |
Landings |
Discard rate (%) |
Discards |
Fisheries with highest discards |
|||||
China |
Chinese small drift gillnet |
2000 |
2 288 713 |
0.5 |
11 501 |
Canada |
Greenland halibut gillnet |
1994 |
10 455 |
23.1 |
3 137 |
Norway |
Cod gillnet in north Norway |
Annual average |
31 000 |
9.1 |
3 100 |
|
Bottom gillnet for cod, saithe, haddock |
|
|
|
|
Iceland |
and ling |
2001 |
63 665 |
3.0 |
1 969 |
|
Surface and bottom gillnet for flatfish, |
|
|
|
|
France |
pollock, cod and tuna |
Average |
26 722 |
6.1 |
1 736 |
Fisheries with highest discard rates |
|||||
United States |
California drift gillnet for swordfish |
|
|
66.0 |
n.a. |
United States |
Northeast bottom multispecies (sink) gillnet |
|
|
31.0 |
n.a. |
EU Mediterranean countries |
Cuttlefish trammel |
|
|
25.5 |
n.a. |
Canada |
Greenland halibut gillnet (cod, pollock) |
1994 |
10 455 |
23.1 |
3 137 |
Norway |
Lumpfish gillnet |
Average |
300 |
23.1 |
90 |
TABLE 22
Percentages of hake discards by year class in
the Argentine hake trawl fishery
Year/year class |
0 |
1 |
2 |
3 |
1990 |
0.82 |
85 |
14 |
0.21 |
1991 |
0.94 |
89 |
10 |
0.12 |
1992 |
0.83 |
86 |
13 |
0.15 |
1993 |
0.90 |
88 |
11 |
0.09 |
1994 |
0.92 |
81 |
18 |
0.49 |
1995 |
0.90 |
84 |
14 |
0.34 |
1996 |
0.93 |
90 |
9 |
0.19 |
1997 |
1.27 |
93 |
5 |
0 |
Source: Dato, Villarino and Cañete, 2000.
FIGURE 2
Percentage of discards by year class in the
Argentinian hake fishery (1990-97)
A.3 DISCARDS BY LARGE MARINE ECOSYSTEM
TABLE 23
Indicative discards by large marine ecosystem
(LME)
Number |
LME |
Recorded discards (tonnes) |
22 |
North Sea |
909 109 |
5 |
Gulf of Mexico |
513 597 |
13 |
Humboldt Current |
439 371 |
52 |
Sea of Okhotsk |
361 905 |
27 |
Canary |
269 205 |
1 |
East Bering Sea |
156 551 |
3 |
California Current |
150 161 |
11 |
Pacific Central-American coastal |
139 396 |
14 |
Patagonian shelf |
138 126 |
17 |
North Brazil shelf |
136 740 |
34 |
Bay of Bengal (including Malaysia) |
130 713 |
32 |
Arabian Sea |
130 272 |
12 |
Caribbean Sea |
130 184 |
4/5 |
Gulf of California/Gulf of Mexico1 |
119 166 |
24 |
Celtic-Biscay shelf |
100 893 |
29 |
Benguela Current |
95 896 |
7/8/9 |
Northeast USA, Scotian, Newfoundland/Labrador1 |
80 151 |
6 |
Southeast United States, continental |
78 745 |
30 |
Agulhas Current |
59 899 |
40 |
Northeast Australian shelf - Great Barrier Reef |
47 655 |
59 |
Iceland shelf |
45 564 |
39 |
North Australian shelf |
42 750 |
2 |
Gulf of Alaska |
41 918 |
28 |
Guinea Current |
40 513 |
24 |
Celtic-Biscay |
37 168 |
25 |
Iberian coastal |
35 605 |
42 |
Southeast Australian shelf |
32 976 |
36/37/38 |
South China, Sulu-Celebes, Indonesian Seas1 |
30 818 |
36 |
South China Sea |
21 405 |
15 |
South Brazil shelf |
20 372 |
26 |
Mediterranean |
17 239 |
23 |
Baltic Sea |
14 203 |
20 |
Barents Sea |
13 455 |
7 |
Northeast United States, continental |
11 533 |
31 |
Somali Current |
8 874 |
36/37 |
South China, Sulu-Celebes Seas1 |
7 521 |
16 |
East Brazil shelf |
7 062 |
21 |
Norwegian shelf |
5 840 |
33 |
Red Sea |
4 832 |
61 |
Antarctic |
2 079 |
19 |
East Greenland shelf |
1 770 |
9 |
Newfoundland/Labrador shelf |
1 242 |
62 |
Black Sea |
715 |
- |
Other LMEs |
676 |
- |
Outside LMEs or not attributable to an LME1 |
2 227 489 |
|
Total |
6 824 186 |
1 As some fisheries harvest from more than one LME, discards in certain areas are difficult to attribute by LME, e.g. distribution of Malaysian discards between the Gulf of Thailand and South China Sea.
Source: discard database.
FIGURE 3 |
A.4 DISCARDS BY COUNTRY AND IN LOW INCOME FOOD DEFICIT COUNTRIES (LIFDCS)
TABLE 24
Landings, discards (tonnes) and weighted
discard rate by country or area (EEZ, not flag state)
Country1 |
Landings |
Discards |
Discard rate (%) |
American Samoa |
460 |
0 |
0.0 |
Angola |
232 325 |
46 594 |
16.7 |
Anguilla |
225 |
0 |
0.0 |
Antigua and Barbuda |
1 369 |
0 |
0.0 |
Argentina |
622 964 |
109 000 |
14.9 |
Aruba |
168 |
0 |
0.0 |
Australia |
97 644 |
120 981 |
55.3 |
Bahamas |
10 253 |
0 |
0.0 |
Bahrain |
8 164 |
2 571 |
24.0 |
Bangladesh |
314 966 |
64 578 |
17.0 |
Barbados |
3 316 |
0 |
0.0 |
Belize |
111 |
284 |
71.9 |
Benin |
8 146 |
41 |
0.5 |
Bermuda |
430 |
0 |
0.0 |
Brazil |
480 574 |
54 892 |
10.3 |
British Virgin Islands |
236 |
0 |
0.0 |
Brunei Darussalam |
1 214 |
3 579 |
74.7 |
Bulgaria |
3 353 |
436 |
11.5 |
Cambodia |
49 343 |
0 |
0.0 |
Cameroon |
61 407 |
367 |
0.6 |
Canada |
789 061 |
90 021 |
10.2 |
Cape Verde |
10 881 |
54 |
0.5 |
Cayman Islands |
123 |
0 |
0.0 |
Chile |
4 360 251 |
89 155 |
2.0 |
China |
14 777 934 |
74 261 |
0.5 |
Colombia |
9 095 |
14 377 |
61.3 |
Comoros |
6 951 |
35 |
0.5 |
Cook Islands |
836 |
0 |
0.0 |
Costa Rica |
2 683 |
2 437 |
47.6 |
Côte dIvoire |
30 000 |
151 |
0.5 |
Cuba |
19 227 |
0 |
0.0 |
Djibouti |
350 |
0 |
0.0 |
Dominica |
1 104 |
0 |
0.0 |
Dominican Republic |
942 |
3 964 |
80.8 |
Ecuador |
24 113 |
91 211 |
79.1 |
El Salvador |
37 678 |
10 397 |
21.6 |
Equatorial Guinea |
5 400 |
27 |
0.5 |
Eritrea |
16 989 |
3 792 |
18.2 |
EU (NEI*) |
12 211 |
8 135 |
40.0 |
Falklands/Malvinas |
228 417 |
11 127 |
4.6 |
Fiji Islands |
20 832 |
0 |
0.0 |
Finland |
104 000 |
200 |
0.2 |
France |
729 517 |
194 268 |
21.0 |
France (Réunion) |
2 722 |
27 |
1.0 |
French Guyana |
9 324 |
49 822 |
84.2 |
French Polynesia |
6 631 |
0 |
0.0 |
Gabon |
25 000 |
253 |
1.0 |
Gambia |
39 098 |
5 124 |
11.6 |
Ghana |
105 936 |
1 445 |
1.3 |
Greece |
35 000 |
17 070 |
32.8 |
Grenada |
1 661 |
0 |
0.0 |
Guadeloupe |
9 641 |
0 |
0.0 |
Guam |
472 |
0 |
0.0 |
Guatemala |
16 100 |
50 950 |
76.0 |
Guinea |
103 913 |
16 684 |
13.8 |
Guinea-Bissau |
50 021 |
18 500 |
27.0 |
Guyana |
26 870 |
29 960 |
52.7 |
Haiti |
398 |
1 402 |
77.9 |
Honduras |
11 815 |
27 335 |
69.8 |
Iceland |
1 969 672 |
45 564 |
2.3 |
India |
2 849 066 |
57 917 |
2.0 |
Indonesia |
3 104 788 |
270 412 |
8.0 |
Iran, Islamic Rep. of |
43 272 |
29 208 |
40.3 |
Ireland |
214 903 |
29 569 |
12.1 |
Japan |
6 491 001 |
918 436 |
12.4 |
Jordan |
116 |
0 |
0.0 |
Kenya |
8 272 |
2 940 |
26.2 |
Kiribati |
16 000 |
0 |
0.0 |
Korea, Dem. Rep. of |
221 253 |
1 112 |
0.5 |
Korea, Rep. of |
197 913 |
995 |
0.5 |
Kuwait |
5 602 |
41 980 |
88.2 |
Liberia |
4 494 |
23 |
0.5 |
Madagascar |
69 184 |
31 618 |
31.4 |
Malaysia |
1 027 276 |
10 377 |
1.0 |
Maldives |
12 599 |
59 |
0.5 |
Marshall Islands |
3 273 |
0 |
0.0 |
Martinique |
5 352 |
0 |
0.0 |
Mauritania |
15 000 |
75 |
0.5 |
Mauritius |
10 694 |
54 |
0.5 |
Mexico |
541 423 |
137 873 |
20.3 |
Micronesia, Fed. States |
5 000 |
0 |
0.0 |
Montserrat |
46 |
0 |
0.0 |
Morocco |
924 450 |
222 457 |
19.4 |
Mozambique |
68 787 |
26 525 |
27.8 |
Myanmar |
880 594 |
27 371 |
3.0 |
Namibia |
522 557 |
13 454 |
2.5 |
Nauru |
425 |
0 |
0.0 |
Netherlands |
110 000 |
14 717 |
11.8 |
New Caledonia |
3 418 |
0 |
0.0 |
Nicaragua |
5 776 |
6 346 |
52.4 |
Nigeria |
190 722 |
2 792 |
1.4 |
Niue |
206 |
0 |
0.0 |
Norfolk Island |
0 |
0 |
0.0 |
Northern Mariana Is. |
2 966 |
0 |
0.0 |
Norway |
2 516 350 |
102 611 |
3.9 |
Oman |
135 957 |
1 384 |
1.0 |
Pakistan |
228 676 |
35 467 |
13.4 |
Palau |
2 103 |
0 |
0.0 |
Panama |
101 964 |
33 483 |
24.7 |
Papua New Guinea |
33 167 |
6 150 |
15.6 |
Peru |
10 291 633 |
350 215 |
3.3 |
Philippines |
744 583 |
7 521 |
1.0 |
Pitcairn Islands |
8 |
0 |
0.0 |
Portugal |
6 303 |
35 605 |
85.0 |
Russian Federation |
400 000 |
361 905 |
47.5 |
Saint Helena |
781 |
0 |
0.0 |
Saint Kitts and Nevis |
295 |
0 |
0.0 |
Saint Lucia |
1 621 |
0 |
0.0 |
Samoa |
7 190 |
0 |
0.0 |
Saudi Arabia |
24 833 |
1 014 |
3.9 |
Senegal |
376 153 |
25 209 |
6.3 |
Seychelles |
4 433 |
22 |
0.5 |
Sierra Leone |
45 910 |
231 |
0.5 |
Solomon Islands |
16 634 |
0 |
0.0 |
Somalia |
4 000 |
0 |
0.0 |
South Africa |
872 935 |
37 570 |
4.1 |
Spain |
6 343 |
212 |
3.2 |
Sri Lanka |
274 760 |
1 367 |
0.5 |
Sudan |
5 094 |
26 |
0.5 |
Suriname |
5 500 |
29 500 |
84.3 |
Syrian Arab Republic |
2 408 |
12 |
0.5 |
Tanzania, United Rep. |
51 147 |
5 934 |
10.4 |
Thailand |
2 752 878 |
27 807 |
1.0 |
Timor-Leste |
381 |
2 |
0.5 |
Tokelau |
200 |
0 |
0.0 |
Tonga |
7 036 |
0 |
0.0 |
Trinidad and Tobago |
6 639 |
8 859 |
57.2 |
Tunisia |
29 295 |
147 |
0.5 |
Turkey |
282 150 |
279 |
0.1 |
Turks and Caicos Is. |
1 310 |
0 |
0.0 |
Tuvalu |
1 100 |
0 |
0.0 |
United Kingdom |
27 343 |
16 654 |
37.9 |
United States |
3 344 438 |
927 599 |
21.7 |
Uruguay |
112 572 |
18 649 |
14.2 |
Vanuatu |
2 930 |
0 |
0.0 |
Venezuela |
213 025 |
96 820 |
31.2 |
Viet Nam |
3 547 346 |
17 826 |
0.5 |
Wallis and Futuna Is. |
917 |
0 |
0.0 |
Yemen |
50 523 |
531 |
1.0 |
Total |
69 580 728 |
5 207 041 |
7.0 |
* NEI: not elsewhere included
1 LIFDCs are shaded in the table.
Values presented for landings are only those corresponding to the discards recorded in the discards database. The discard rates presented do not represent the aggregate discard rate for a country's fisheries.
Table 24 is provided for record purposes only. Because of the bias in the discard database towards fisheries that discard, discard rates and total discards on a country-by-country basis are not necessarily representative of total discards or discard rate of the aggregate fisheries of the country. Only complete records are used in the table so that some fisheries with high discard rates, but for which landings information is unavailable are not included. The table excludes tuna and HMS fisheries.
Table 24 also highlights discard information from low income food deficient countries (LIFDCs). The table does not provide a total of discards from these countries but is intended to draw attention to countries and fisheries where further actions may be directed to improve bycatch utilization. As the table is based only on records where the volume of discards is available certain fisheries are not included.
A.5 DISCARDED SPECIES AND INCIDENTAL CATCHES
TABLE 25
Commonly discarded species in different
fisheries (indicative)
Fishery |
Commonly discarded species |
Penaeid shrimp trawl |
Small finfish caught as bycatch. Species groups include Leiognathidae (ponyfish), Nemipteridae (threadfin), Trichurius sp. (hairtails), Decapterus sp., Saurida sp. (Synodontidae), small shrimp, sharks and rays, as well as jellyfish and juveniles of many commercial whitefish species such as croakers, snappers, and emperors |
Nephrops trawl |
Juvenile whiting, haddock, cod; broken, undersized Nephrops and flatfish |
Finfish (roundfish) trawl fisheries |
Juvenile commercial species, in particular demersal species such as whiting, haddock, hake, Sciaenidae and lower value commercial species such as horse mackerel, Rastrelliger and elasmobranchs |
Hake trawl |
Small hake and horse mackerel (all fisheries), kingklip and rattails (Africa), arrowtooth flounder, dogfish and ratfish (North Pacific) |
Flatfish trawl |
Juveniles and target species under MLS; molluscs, echinoderms (sand urchins and starfish), crabs, rajids. Cod, haddock, whiting, plaice, saithe, dab, dogfish, shrimp and Nephrops (EU). Arrowtooth flounder is a major component of discards in the GOA/BSAI fisheries for yellowfin sole, flathead sole and other flatfish |
Deepwater trawl |
Teleosts including grenadiers, whiptails, rabbitfish and oreos; chondrichthyans such as birdbeak dogfish (Deania), batoids and chimaeroids |
Small pelagics midwater trawl |
Small sizes of target species and non-target species such as horse mackerel in mackerel fisheries, horse mackerel (EU countries), sardine, pilchard, mackerel and sprat. Small-sized fish of the target species may be discarded as a result of highgrading in the quota-managed European fisheries or because processing equipment cannot handle smaller sizes. Dolphins (1.4 dolphins/100 tow-hours in French and Irish tuna fisheries) and sunfish are caught incidentally |
Purse seine for small pelagics |
Primarily non-target small pelagics including horse mackerel, Scomber japonicus, Boops, Belone sp., jellyfish, juveniles of other species and small quantities of sharks |
Tuna purse seine |
Non-commercial tunas (e.g. bonito, dogtooth tuna), rainbow runner, dolphinfish, jacks, shark, billfish, mantas and undersized skipjack and yellowfin, dolphins. Large quantities of jellyfish are discarded in the bluefish and bonito fisheries in Turkish waters. Incidental catches of dolphins |
Tuna/HMS longline fisheries |
The principal discards include Prionace glauca (blue shark), which is probably the most commonly discarded species, Carcharinus sp. and other sharks, shark/ marine mammal-damaged fish, albatross, petrels and other seabirds. Frigate tuna, Kawakawa, Indo-Pacific king mackerel, and narrow-barred Spanish mackerel |
Bottom longline |
Non-quota species. Arrowtooth flounder GOA/BSAI fisheries), starry ray, dab and redfish (Iceland, Faeroe Islands), hake, shark and kingclip (South Africa), and macrourids and rajids in the CCAMLR area |
Gillnet fisheries |
Dogfish, skate, sculpin (Canada), cod, haddock, plaice, saithe and dab (Europe) |
United States Northwest |
Molluscs and crustaceans. Trawlers are obliged to discard large volumes of |
Pacific groundfish fisheries |
crabs. Many species of discarded shellfish survive.1 These include lobster, crab, scallop and oyster. Discard estimates can prove difficult if landings are expressed in numbers, weight of meat or volume (e.g. in bushels) |
Otter trawl ICES VIIe, f,h |
Benthos discarded included echinoderms, Marthasterias glacialis, Asterias rubens, Ophiura ophiura and whelk (Buccinum undatum) (Lart et al., 2002b) |
1 Shrimp, giant spider crabs and ascidians have a high mortality. In the Bass Straits scallop dredge fishery under 3 percent of dredged items are bycatch, most of which are undamaged when discarded.
TABLE 26
Incidental catch of seabirds, turtles and
marine mammals in selected fisheries
Fishery |
Species |
Incidental catch rate |
Measures/notes |
Source |
Danish bottom set gillnet |
Harbour porpoise |
Mean 5, 129 (1987-2001) |
Use of pingers in cod/wreck fishery judged 100% effective |
STECF/SGFEN (2002), quoting Vinther and Larsen, 2002 |
Netherlands horse mackerel trawl |
Dolphin |
Nine dolphins in six tows |
|
BIOECO/93/017 Morizur et al., 1996 |
France hake pelagic trawl |
Dolphin |
1.2 dolphins/100 tow-hours |
|
BIOECO/93/017 (data 1994) Morizur et al., 1996 |
France pelagic trawl for seabass |
Dolphin |
1.5 dolphins/100 tow-hours |
|
BIOECO/93/017 (data 1994) Morizur et al., 1996 |
Ireland albacore midwater trawl |
Dolphin |
1.4 dolphin/100 tow-hours (French), sunfish |
No bluefin quota except as bycatch |
BIOECO/93/017 (data 1994) Morizur et al., 1996 |
United Kingdom bass pelagic trawl - English Channel |
Dolphin |
61 common dolphin in 122 monitored tows, 2001 and 2002 |
Tows in mackerel, pilchard and blue whiting fisheries monitored but 0 mortality |
STECF/SGFEN, 2002 |
Netherlands pelagic freezer trawl |
Dolphin, pilot whale |
Eight white-sided dolphin, common dolphin, pilot whale, 0.06 mm per haul |
Observer reports, study of seasons and distribution of interaction |
Couperus, 1997 (data 1995-1996) |
Spain longline |
Mammals, seabirds, turtles |
Mammals, seabirds, turtles |
|
Caswell et al., 1998 |
France thonaille |
Dolphin |
0.6-1.2 per 100 tuna caught Stenella coeruleoalba (striped dolphin) |
Mandatory pingers, ACCOBAMS |
STECF/SGFEN, 2002 |
Australia states Queensland inshore commercial |
Dugong |
n.a. |
|
Harris, A. 1997 |
United States Western Pacific pelagic longline |
Seabirds, albatross |
3 073 albatross (two spp.). 0.013 (tuna sets) to 0.76 (swordfish sets) birds per set |
See FMP and EIA |
NMFS/NOAA, 2001 (data 1994-1999) |
United States Pacific halibut birds |
Birds |
6.1 per mill. Hooks |
Tori lines, research on video monitoring, fisher interviews |
IPHC Web site (Alaska) fisher interviews |
Peru small-scale longline - northern Peru |
Waved albatross (Diomedea irrorata) |
0.74 to 1.75 birds/1 000 hooks |
Change from gillnetting to avoid cetacean bycatch, fisher interviews |
Guillen, Jahncke and Goya, 2000, p. 132 (data 1999) |
United States Atlantic HMS |
Birds, turtles |
1 307 turtles, 48 birds, 200 marine mammals |
|
US bycatch matrix |
Spain Mediterranean swordfish longline |
Turtles |
0.18-2.73 per 1 000 hooks |
|
Cramer, Bertolino and Scott, 1995 (data 1986-1995) |
Spain Mediterranean surface and bottom longline |
Corys shearwater (Calonectris diomedea) |
0.16 to 0.69 birds per 1 000 hooks |
437-1 836 shearwaters killed annually in the area |
Belda and Sanchez, 2001 |
All SPC tuna purse seine |
Marine mammals |
3.8 per 1 000 sets |
SPC observer data |
P. Sharples SPC, pers. comm. (observer data 1997-2003) |
All SPC tuna purse seine |
Turtles |
0.9 per 1 000 sets |
SPC observer data |
P. Sharples SPC, pers. comm. (observer data 1997-2003) |
All SPC tuna longline |
Birds |
0.12 per 1 000 hooks |
SPC observer data |
P. Sharples SPC, pers. comm. (observer data 1997-2003) |
All SPC tuna longline |
Reptiles |
0.02 per 1 000 hooks |
SPC observer data |
P. Sharples SPC, pers. comm. (observer data 1997-2003) |
All SPC tuna longline |
Marine mammals |
0.02 per 1 000 hooks |
High % alive when hauling, survival rate unknown |
P. Sharples SPC, pers. comm. (observer data 1997-2003) |
IATTC purse seine |
Dolphins |
2 129 dolphins killed |
Quota, international agreement, observers, experimental fishing |
IATTC, 2001 (data 1999) |
United States/IATTC tuna dolphin set purse seine |
Dolphins encircled |
2.34 million per year - number encircled, most are released, >300 per set |
See IATTC rules |
Southwest Fisheries Science Center, 2002 (data average of programme years) |
Notes
With regard to the absolute levels of cetacean and endangered species discards, it should be noted that the entanglement and mortality of, for example, a single North Atlantic right whale (population 300) is of greater concern than the capture of several common dolphins (population 200 000 in the area).
Records of discards of lesser-known aquatic animals such as saltwater crocodiles and sea snakes are uncommon.
Source: discard database.
A.6 EXAMPLES OF TRENDS IN DISCARD REDUCTION AND INCREASE
As this report gives a substantially lower estimate of global discards, further evidence of this reduction is provided in Table 27.
TABLE 27
Examples of discard reduction in selected
fisheries
Area |
Fishery |
Discard reduction |
Period |
Principal reasons |
Source |
21 |
Canada northern shrimp |
Bycatch reduced from 15.2 to 5.6% of catch. |
1991-1994 |
BRD (Nordmore); reduction in groundfish stocks, responsible fishing practices, requirement to change area |
Duthie, 1997a |
21 |
US Atlantic pelagic longline |
16.5% for pelagic shark 22.1% for large coastal shark |
2001 compared to 1999-2000 average |
Time, area closures |
NMFS/NOAA, 2003 |
27 |
France Nephrops and whitefish trawl |
86-100% of fishers believe that discarding has declined |
2000 |
|
Agricultural Economics Research Institute, 2000 |
27 |
Norway shrimp trawl |
... greatly reduced, resulting in improved catch handling times and quality of the shrimp catch |
n.a. |
Sort-XTM BRD |
MacMullen, 1998 |
31 |
Central American shrimp fisheries |
... [bycatch]...caught was still high (between 90 and 97% of the total catch) but ... utilization of the bycatch has increased |
|
Growing consumption of bycatch |
FAO workshop, Cuba, 1997 |
31 |
Gulf of Mexico shrimp trawl (United States) |
40% reduction in finfish bycatch mortality; 10% increase in shrimp catch (2001); red snapper (main discard) landings doubled |
In comparison with1998 levels |
FMP and BRDs |
Federal Register, 2003, p. 11512 |
41 |
Argentina |
Juvenile hake |
Late 1990s |
Use of BRDs |
IMARPE |
47 |
South Africa, West Coast rock lobster |
Major reduction in discards in late 1990s |
|
Increase in MLS |
Poseidon Aquatic Resource Management Ltd, 2003, p.75 |
51 |
Madagascar shrimp trawl |
Bycatch reduced by 49% |
2000 |
Use of BRDs |
Mounsey, 2000 |
57 |
India - Visak shrimp freezer trawl |
Early 1990s |
|
Freezer fleet has disappeared |
BOBP-IGO, pers. comm. |
57 |
Myanmar trawlers |
60% down to 7-8% for trawl fleet |
Mid-1990s to 2003 |
Building of fishmeal plants, use for animal/fish feed/human consumption |
Myanmar Fisheries Federation, 2003, pers. comm. |
67 |
BSAI/GOA |
See Tables 28 and 29 |
|
|
|
71 |
Western Central Pacific |
... available quantitative information indicates that there has been a considerable increase in the utilization of the fishery catch over the last decade |
1986-1996 |
|
Harris, 1997 |
87 |
Peru hake demersal trawl |
A significant reduction from 30% in 1996 |
1996 - late 1990s |
Use of juveniles and other bycatch for surimi and fish blocks |
R.G. Carrasco, IMARPE, pers. comm. |
|
United States (in general) |
In general, discard levels in the United States have declined over the past several years |
1994-1998 |
... [attributed to] ... new technologies and management measures ... decline in stocks ... increased retention of fish previously discarded |
Alverson, 1998 |
|
Various countries |
Unknown |
|
Legislation designed to reduce bycatch and/or discards in place in over
30 countries |
Poseidon Aquatic Resource Management Ltd, 2003 |
|
Global/high seas shark |
Unknown |
2000-2003 |
Implementation of the IPOA on sharks. United States, EU, Costa Rica and others require landing of carcasses |
United States legislation, Council Regulation (EC), 2003 |
A.6.1 Declining discards in Alaskan and United States West Coast fisheries
The walleye (Alaska) pollock fishery in the North Pacific is the worlds largest demersal whitefish fishery. Over 90 percent of landings are harvested by midwater trawl and the fishery represents approximately 25 percent of United States landings by volume. The following tables show the decline in certain categories of discards in recent years in the BSAI fishery.
TABLE 28
Estimated pollock and non-target groundfish
total and discarded catch in directed BSAI pollock fisheries from 1997 to 2000
(tonnes)
Year |
Total catch |
Total discarded |
Discards (% total catch) |
1997 |
1 097 657 |
41 505 |
3.78 |
1998 |
1 022 374 |
10 472 |
1.02 |
1999 |
957 713 |
9 704 |
1.01 |
2000 |
1 109 250 |
12 81 |
1.1 |
Source: Bernstein et al., 2002 (Table 7).
TABLE 29
Average rate of incidental catch of halibut,
crab and salmon in the directed BSAI pollock fishery from 1997 to
2000
Year |
Per tonne of groundfish |
||
Halibut (kg) |
Numbers of crab |
Numbers of salmon |
|
1997 |
0.243 |
0.026 |
0.062 |
1998 |
0.345 |
0.070 |
0.066 |
1999 |
0.180 |
0.003 |
0.077 |
2000 |
0.112 |
0.001 |
0.062 |
Note: all incidental catch of these species must be
discarded.
Source: Bernstein et al., 2002 (Table 9).
Reasons for the reduction in BSAI/GOA discards
The reasons for these declines are closely linked to the management regimes for the BSAI/GOA fisheries and require some understanding of the complex nature and history of these fisheries (see references for details). Some of the principal reasons for effective bycatch management are that:
BSAI/GOA fish stocks are not overfished;[134]
there are strong incentives for bycatch reduction;
enforcement is effective;
bycatch is cooperatively managed; and
fishery bycatch information is used as a real-time management tool.
Incentives
When bycatch limits on crab, salmon and halibut are reached, the legislation requires that the fishery be closed, creating a strong incentive to avoid bycatch. The bycatch of individual vessels is published, creating peer pressure on vessel operators.
Effective enforcement
A 100 percent observer coverage (larger vessels) ensures that all bycatch and discards are recorded. Demersal finfish discards are recorded by weight. Salmon and crab discards are recorded by number. Regulations require that all salmon, crab and halibut be discarded. Vessel operators actively cooperate with observers to ensure that discard records are accurate.
Cooperative management of the bycatch allocation
The Pollock Conservation Cooperative (PCC) and High Sea Catchers Cooperative (Joint Report of the Pollock Conservation Cooperative and High Sea Catchers Cooperative, 2002), operational since 1999, effectively acts as a voluntary/cooperative ITQ system, giving many of the benefits of an ITQ system to the eight PCC members, which control approximately 37 percent of the catch allocation of the directed pollock fishery.
The members contract a private firm to which observer data, including bycatch data, are uploaded once or twice a day. Two observers on board each vessel sample 98.9 percent of hauls. Groundfish discards are less than 0.5 percent. Information on bycatch levels is shared between operators in near real time, identifying bycatch hotspots and allowing vessels to move rapidly to grounds with low bycatch. The cooperative arrangement has forfeiture (penalty) clauses for breach of bycatch limits and there has been full compliance with these limits. The benefits of the cooperative management regime have included:
improved processing yield (larger fish) and more time to search for larger fish (no race for fish);
processing at optimum speed for product quality and yield (recovery rate);
reduced capitalization in vessels and processing equipment (although there was increased investment to vary product mix and meet market requirements);
substantial contributions to fisheries research;
reduced bycatch of unwanted species through movement to low bycatch areas; and
reduction of the Olympic-style fishery (race for fish), reduction of over 30 percent in effort and increased economic rent generation
Similar cooperative arrangements with regard to bycatch exist in the Pacific whiting fishery (see Box 7), Weathervane scallop fishery in the United States (Brawn and Scheirer, 2002) and the Hoki fishery in New Zealand (Hoki Fishery Management Company, 2003).
BOX 7 Pacific Whiting Conservation Cooperative (PWCC) members have achieved significant reductions in bycatch. Pacific whiting, like Bering Sea pollock, is harvested using midwater trawl nets. Bycatch rates for both fisheries are from 1 to 2 percent. The whiting catcher/processor fleet operating within the construct of a cooperative achieves even greater bycatch reductions. The bycatch rate for yellowtail rockfish decreased by more than 60 percent from 2.47 kg of yellowtail rock per tonne of whiting under the race for fish to 0.96 kg per tonne under the cooperative arrangement. During the same period, yellowtail rockfish bycatch by smaller trawl vessels delivering to mother ships increased from 3.43 to 6.51 kg per tonne. A major contributor to the reduction in bycatch is the fishers ability to discontinue fishing in high bycatch areas without sacrificing harvesting opportunities. To help avoid bycatch hotspots, PWCC members report catch and bycatch data electronically to Sea State, a private sector firm specializing in fisheries data collection and analysis. Sea State collates the data and reports back to PWCC vessels on a real-time basis, advising vessel captains to avoid areas in which high bycatch is likely to occur. Because they do not have to race for fish, boats can take the time to move to areas with low bycatch. |
A.6.2 Examples of increases in discards
There are few examples of fisheries with increasing discards. Some deepwater fisheries are producing discards that did not hitherto exist, although active market promotion is under way for such unfamiliar species. Quota restrictions in EU fisheries are resulting in high discard rates, although overfishing reduces the absolute quantity of discards. There is evidence of substantial discarding in a number of major fisheries in the Russian Far East.
[134] Out of 244 fish
stocks only two are considered to be overfished (NMFS, 2001). |