Scope for Efficient Multinational Exploitation of North-East Atlantic Mackerel
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| ||||||||||
|
|
(million) |
|
(kg) |
|
(kg) |
|
(kg) |
|
(kg) |
|
(kg) |
|
0 |
4252 |
0.00 |
0.000 |
0.0000 |
|
0.0000 |
|
0.0000 |
|
0.0000 |
|
|
1 |
3645 |
0.09 |
0.091 |
0.0000 |
|
0.0000 |
0.178 |
0.0000 |
0.178 |
0.0000 |
0.123 |
|
2 |
3709 |
0.60 |
0.191 |
0.0587 |
0.291 |
0.0033 |
0.297 |
0.0061 |
0.299 |
0.0020 |
0.191 |
|
3 |
3095 |
0.87 |
0.243 |
0.1090 |
0.389 |
0.0247 |
0.360 |
0.0298 |
0.362 |
0.0256 |
0.252 |
|
4 |
3168 |
0.98 |
0.302 |
0.1360 |
0.403 |
0.0294 |
0.418 |
0.0470 |
0.408 |
0.0344 |
0.323 |
|
5 |
1989 |
0.98 |
0.359 |
0.1729 |
0.458 |
0.0593 |
0.460 |
0.0771 |
0.456 |
0.0755 |
0.358 |
|
6 |
1213 |
0.99 |
0.409 |
0.1090 |
0.530 |
0.1026 |
0.509 |
0.1358 |
0.488 |
0.1431 |
0.416 |
|
7 |
1155 |
1.00 |
0.441 |
0.0762 |
0.540 |
0.1074 |
0.553 |
0.0828 |
0.539 |
0.1166 |
0.463 |
|
8 |
575 |
1.00 |
0.473 |
0.0593 |
0.565 |
0.1128 |
0.596 |
0.1250 |
0.566 |
0.1179 |
0.482 |
|
9 |
292 |
1.00 |
0.510 |
0.0531 |
0.601 |
0.1287 |
0.602 |
0.1286 |
0.576 |
0.1536 |
0.538 |
|
10 |
153 |
1.00 |
0.538 |
0.0662 |
0.631 |
0.1723 |
0.632 |
0.1337 |
0.629 |
0.1602 |
0.538 |
|
11 |
126 |
1.00 |
0.517 |
0.0625 |
0.632 |
0.0969 |
0.664 |
0.1033 |
0.650 |
0.0808 |
0.561 |
|
12+ |
203 |
1.00 |
0.609 |
0.0970 |
0.754 |
0.1626 |
0.734 |
0.1308 |
0.715 |
0.0904 |
0.619 |
Data in columns 2 to 4 for
,
, and
are those used in ICES (2000) medium-term modelling projections starting January 1, 2000, for the “Northern” mackerel stock made up of the western area including the North Sea and catches taken in international waters in ICES Division IIa.
Selectivity coefficients
are catch in numbers at age for Western Atlantic mackerel in ICES (2000) Table 3.2.1.1, divided by initial stock numbers in column 2, and normalised to sum to one across a. Weights in catch 
are for Western Atlantic mackerel in ICES (2000) Table 3.2.1.2.1. Data for Western mackerel rather than for North-East Atlantic mackerel as a whole are used for modelling the “Northern” stock because of the predominance of the western stock. ICES (2000) uses relative weights for calculating stock weights for North Sea, Western and Southern mackerel components of 0.02, 0.73 and 0.25 respectively.
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