Gilis, Ch.

Open Marine Archive

-205- Herring 
Near N. Seas 
% 
40 
:L[L:: 
2' 3' 4' 5' 6' ?· 8' 9' >9' L--
4o 
30 
20 
10-
SANOETTIE 
% 2• 3' 4' 5' 6' ?' o· 9' >9' 
40 =~ 
% z· 3' 4' 5' 6' r o· 9' >9' 
40 .-----
30 EAST ANGLIA 
20 
10 
-
2· 3' 4' 5' 6' r o• 9' > 9' 
Figure 16. Age composition of spawning herring in the 
Dogger, Sandettie, and Channel areas (trawl), and age 
composition of herring from the East Anglian fishery 
(drift-net). 
The Belgian Herring Fisheries in 1956-1957 
(30. July 1956- 19. January 1957) 
(Figure I 7; Tables 39- 49) 
The North Sea - English Channel 
1. Regions - fishing gear 
The statistics of the herring fishery distinguishes 
between three, more or less well-defined regions, 
viz., r) the northern area, where the fishery is 
mainly · centred in the Fladen Ground area; z) 
the central area, where fishing is carried out on 
the Gut, the Dogger Bank, and in the waters west and 
south of this bank, and 3) the southern area, 
where fishing is carried out in a rather narrow 
zone situated between the "Hinders" Bank and 
the entrance to the eastern English Channel, 
including the Sandettie area. 
In the northern and central areas of the North 
Sea fishing was carried out exclusively with the 
otter-trawl, whereas in the southern area nearly 
all catches were obtained by the pelagic trawl, 
towed by two trawlers fishing together. 
This fishery yielded in all 3,277 tons of fish, of 
which 3,038 tons were herring; 6r6 tons of the 
herring were caught with otter-trawl (20.3%) 
and the pelagic trawl took 2,422 tons (79·7%) . 
2. Otter-trawl: fishing effort- landings 
Tables 39--41 give records of fishing effort and 
yields obtained by vessels operating with the 
otter-trawl. Only 9 trawlers participated in the 
fishery and made 20 trips during the season 
(Table 39). The catches were mainly composed of 
herring (Table 40), the yield of which totalled 
6r6 tons (Table 41) or 76.5% as against r,228 
tons in the previous season. The average catch 
per roo F. H. x H. P. (47 kg.) was 35 kg. or 42.7% 
lower than in the previous season (82 kg.). 
3· Pelagic trawl: fishing effort - landings 
This fishery was localized in the extreme south 
of the North Sea and the eastern English Channel. 
Owing to the lack of remunerative catches, 
the activity of the trawlers was very restricted. 
The first catches from this region were landed 
at the beginning of October and the last on rg. 
January 1957. 
In Table 42, a survey is given of the fishery 
effort and yields, in comparison with the previous 
season. In the 1956 season 56 trawlers were engaged 
in the fishing (87 in 1955-56) and 381 (1,179) 
voyages were made. 
The total catch amounted to 2,471 tons con-
sisting of 2,422 tons herring, or g8.o2%, 2 tons 
or o.oS% mackerel, 3 tons or o.r3% other pelagic 
species, and 44 tons or 1.77% demersal species. 
Table 42 gives further details about the landings 
made with the pelagic trawl. The average catch per 
rooF. H. x H . P. reached only I3J kg. as against 
302 kg. in 1955- -56, or 54.6% less. This average 
yield varied considerably from month to month. 
It reached its maximum in January 1957 with 
194 kg. and its minimum in December with 126 kg. 
The Herring Stock 
1. Southern North Sea 
As the landings of herring from the northern 
and central areas of the North Sea were rather 
scarce and irregular it was not possible to obtain 
a sufficient number of samples for studying the 
biological composition of the stocks present there. 
Thus these studies have been limited to the stocks 
inhabiting the southern North Sea. 
-206-
Table 39· Number of trips with otter-trawl and fishing effort 
:\umber of trips Fishing effort (r,ooo F.H. x H.P.) 
Months Xorth. Centr. South. Total North. Centr. South. Total 
July . . . . . . . . . . . . . . . . . . . I 171 171 
August ........ . . . . . . .. . . 6 7 793 27 820 
September .... . .... . . ... . 
October ....... . .... . . . . . 54 54 
November. . .. . ........ . .. 4 7 11 232 35 267 
Total 1956 • • • • • • • • • • • • • 0 • 12 7 20 1,250 27 35 1 ,312 
Total 1955 . . . .. . . . . . . .... 8 25 19 52 512 889 91 1,492 
Table 40. The total yields by otter-trawl vessels Table 42. 
Species 
P elagic Herring . ....... . . .. .. . . 
Mackerel ..... .. . .. . ... . 
, Horse Mackerel ..... . ... . 
Tons Ofoo 
6r6 765 
87 107 
3 4 
Fishing effort and yield of the fishery with pelagic trawl 
Average Fishing 
Number Total catch per effort 
of catch r oo F.H. (roooF.H. 
X X 
Demersal Haddock ............ . 
Cod .. . .... .... . ..... . 
Saithe . ........ . . . .. . . 
Whiting . .. . . .. . . . . .. . 
, Others . . ... .. . . . . .. .. . 
Total pelagic species ...... . . . .. . 
Total demersal species ...... ... . . 
Ij IS 
7 9 
21 26 
45 55 
12 r6 
706 876 
lOO 124 
Months trips (tons) H.P. (kg.) H.P. ) 
October ...... 32 193 I37 I41 
November .... 241 I , j85 137 r,r6o 
December .. .. 87 503 r26 401 
]anuar .. . .... 21 141 I94 72 
Total 1956~57 381 2,422 Mean 137 1,774 
Grand Total ..... . . . ...... .. . . . 8o6 1,000 Total r955~56 . I, I 79 II,jz8 Mean 302 3,813 
Table 41. The yields of herring (otter-trawl) 
Total catch (tons) Average catch per roo F .H. X H.P. (kg.) 
Months North. Centr. South. Total North. Centr. South. Total 
July . . . . . . . . . . . . . 36 
August . . . . . . . . . . . . . . . . 303 34 
September .. . . . . . .. . . . . 
October . . . . . . . . . . . . . . . 20 
November . . . . . . . . . . . . . 211 12 
Total 1956 . . . . . . . . . . . . . 570 34 12 
Total 1955 . . . . . . . . . . . . . 243 8!4 172 
The material investigated consisted of I6 samples 
comprising r,050 fish; they were collected in Oc-
tober (r4o), November (560), December r956 (245), 
and in January I957 (I05). · . 
Table 43 shows the size distribution of the 
herring from month to month during the season. 
The average weight and the percentage of males 
are also recorded. The average size of the fish 
(25I mm.) was lower than in I955-56 (269 mm.), 
the average weight was ro6 g. as against 134 g. 
in 1955-56. 
As to the matnritv, it is evident from Table 44 
that stage V was . greatly predominant during 
October and stages VIII-II in the othermonths. 
As in earlier investigations the quantity of intesti-
nal fat was estimated. The results are shown in 
Table 45· 
36 21 2I 
337 38 125 4I 
20 37 37 
223 91 35 84 
6r6 46 125 35 47 
1,229 48 91 r88 Sz 
The age composition is shown in Table 46. 
It appears that the 3-year-old fish were predomi-
nant during all months. The sequence of the most 
important year-classes, as to their relative strength 
proved to be as follows:-I953 (5230fo0), 1952 
(r6JOfo0), and 1951 (rr6 Ofu0). 
The age composition of the catches from year to 
year is given in Table 47· This table deals with the 
4-year period from 1953--54 to rg56-57. The 
youngest year-classes seem to predominate during 
this period. 
The average length of the herring and the 
growth-rate during the first year (L1) is given in 
in Table 48. 
The number of vertebrae varies between 54 
an 6o (Table 49). The spines with 57 vertebrae 
-207- Herring 
Near N. Seas 
Table 43· Size, weight, and sex (Ofo0) 
Southern North Sea E. Chan. 
Total Total Dec.-
cm. Oct. Nov. Dec. Jan. 1956-57 rg55-56 Jan. 
31 
30 
2g 
28 
27 
26 
25 
24 
23 
22 
2! 
20 
14 23 r6 _38 23 
43 So 37 124 ;r 
50 77 37 II4 70 
136 II2 53 172 rr8 
93 86 73 133 g6 
rzr gr go 57 go 
293 r;o zoo 162 206 
207 236 294 124 215 
22 ro2 r8o ;6 g5 
14 14 20 I 2 
7 7 4 
Total . . IOOO IOOO IOOO 1000 IOOO 
Average 
length, 
mm. . 253 254 246 264 251 
Mode, 
2 
22 
2 
IOOO 
26g 
41 
;r 
82 
rrS 
;r 
88 
I 53 
253 
94 
23 
6 
IOOO 
254 
Stages 
I ... .. 
II ... . 
III ... 
IV ... . 
V .... . 
Vl ... . 
VII .. . 
VII I-ll 
Total .. 
Table 44· Stages of maturity (Dfo0) 
Southern North Sea E. Chan. 
Total Total 
Oct. Nov. Dec. Jan. 1956-57 1955-56 
Dec.-
Jan. 
rS 
6 
29 4 8 6 
36 34 !6 10 24 
57 
879 266 
4 
8 
r6 
z88 
7 2ro r 3 5s 
29 !6 II 
ZI 430 . 939 990 595 
!000 IOOO IOOO IOOO IOOO 1000 
Table 45· Quantity of intestinal fat (0 / 00) 
zg 
35 
912 
IOOO 
Southern North Sea E. Chan. 
Total Total Dec.-
Quant. Oct. Nov. Dec. Jan. 1956-57 1g55- 56 Jan. 
cm. . . 24 23 23 27 23 28 23 0 . . . . . 164 184 139 II4 I)O r6; 
818 
13 
2 
265 
712 Average I · · ·· · 743 738 829 876 797 
weight, + · · · · · 79 46 24 10 40 !2 
g. . . . . I 41 127 gg 12! I06 134 
47g 
IIO lVI..... I4 32 8 13 !2 
MalesDfoo 521 477 539 457 495 471 Total.. rooo rooo 1ooo rooo rooo IOOO 
r.8s 
IOOO 
I.76 
dominate and the vertebral average was found to 
be 56.595. 
Finally Table 50 gives the number of keeled 
scales (K2) for each month. The average number 
for the whole season was r4,82o. 
Stomach analyses were made on all herring 
investigated. Only I.7 contained food, mostly 
remains of copepods. 
2. The English Channel 
The three samples investigated were taken from 
catches made off Dieppe dming the period Decem-
ber rg56 to January 1957. A total of 170 herrings 
was studied. 
The size distribution, the average size, and the 
weight of the herring can be seen in Table 43· 
The average length of the fish vvas 254 mm., the 
average weight rro g. 
The maturity and the quantity of intestinal fat 
are given in Tables 44 and 45- The greatest part 
of the stock was just spent or recovering spents, 
and the small quantity of fat is in good agreement 
with that fact. 
The age composition is shown in Table 46. 
Here also the 3-year-old fish is predominant 
_ (5200fo0). The 3-5-year-old herring (year-classes 
I953-I95I) contributed altogether 792 Ofoo of the 
total catch. 
The number of vertebrae varies between 54 and 
58 (Table 49), with mode 57 and average 56.659. 
Index . r.g4 r.g3 I.go 1.90 1.92 
2 
3 
4 
5 
6 
7 
8 
9 
IO 
> ro 
Total ... 
Age 
2 
3 
4 
5 
6 
7 
8 
9 
10 
> IO 
Table 46. Age (Dfo0) 
Southern North Sea E. Chan 
Year- Total Dec.-
class Oct. Nov. Dec. Jan. 1956- 57 Jan. 
1954 
1953. 
rgsz 
I95I 
I950 
I949 
Ig48 
I947 
I946 
<I946 
IS Ij 9 
564 466 679 384 
iA3 175 
I20 I 19 
98 70 
30 53 
23 24 
34 
7 27 
15 
IJI 22! 
70 154 
65 39 
5 2g 
9 rg 
14 67 
9 39 
9 48 
IO 
523 
167 
rr6 
68 
29 
14 
2g 
25 
r8 
6 
520 
136 
136 
6s 
78 
32 
7 
7 
13 
IOOO IOOO IOOO IOOO 1000 IOOO 
Table 47· Age composition of the catches 
during 1953(54- 1956/ 57 (Dfoo) 
Southern N orth Sea 
1953-54 
4 
268 
225 
!28 
rq 
122 
82 
23 
r8 
r6 
Season 
22 2 
rr6 
8; 
Sz 
90 
SI 
24 
24 
rgss- s6 rgs6-s7 
13 
524 
!64 
III 
69 
35 . 
20 
z8 
21 
IS 
-208-
Table 48. Average lengths by age and the value of L1 (mm.) Table 48a. Value of L1 (mm.) 
Southern North Sea Southern North Sea 
Mean Mean Mean Mean 
Brood Oct. Nov. Dec. Jan. 1956-57 1955-56 Ll Oct. Nov. Dec. Jan. 1956-57 1955-56 
1954 210 225 231 223 205 1954 130 161 148 153 135 
1953 241 238 235 239 238 245 1953 129 !26 122 123 125 126 
1952 260 260 238 265 260 261 1952 !26 125 124 131 126 122 
1951 271 273 268 277 272 277 1951 120 !28 119 132 !26 110 
1950 282 284 283 278 283 283 1950 128 127 130 uS 127 108 
1949 283 290 z86 296 289 z88 1949 121 117 II8 133 119 II 3 
1948 294 294 292 305 295 290 1948 IIO II6 111 134 II6 Ill 
1947 296 298 291 295 zgo 1947 108 103 IIO ro8 114 
1946 294 296 294 296 296 294 1946 113 II6 8g 117 113 
Table 49· Vertebrae (V.S. Ofo0 ) 
Southern North Sea Channel 
Total Total 
V.S. Oct. Nov. Dec. Jan. 1956-57 1955-56 Dec.-Jan. 
6o ... .. . . ..... ... . 4 
59 . . ... .. .. .... ... 9 10 5 I 
ss •• • ••• • • •• •• •• 0 . 52 44 82 30 52 67 67 
57 ..... .. .... . . . . . 545 490 517 574 532 510 591 
56 .............. .. 373 429 362 366 382 393 281 
55 ••• • 0 ••••••••• • • 22 35 22 20 25 28 55 
54 • • 0 ••••••• 0 • • • • • 8 2 4 3 6 
Total ••••••••• 0 •• 0 1000 1000 1000 1000 1000 1000 1000 
Average ........... s6.61 2 56·540 s6.6g4 56.644 56·595 56.619 56.659 
Standard error ... . . 0.6584 o.6481 0.7396 0.6243 0.6531 0.6642 0.7890 
Fluctuation mean .. . 0.1917 0 .0941 0.1638 0.2095 0.0694 o.o686 0.2077 
Table so. Keeled scales (K 2) in Ofoo 
Southern North Sea Channel 
K2 Oct. Nov . 
19 .... . .... . .. . . .. 
18 .... .. ... .... . .. 2 
17 . . . . . . . . . . . . . . . . 29 22 
r6 •• • ••• ••• 0 0 •• • • • 169 152 
15 •••• • •• • • 0 ••• ••• 478 472 
14 ••••••••••• 0 •••• 280 3°7 
13 ..... ..... ... ... 44 43 
12 ••••••••••• • • 0 • • 2 
Total . ... ......... 1000 1000 
Average ........... 14.86o q .8or 
Standard error . .. .. 0.8497 0.8462 
F luctuation mean . .. 0.2458 0.1213 
Table 50 gives the number of keeled scales (K2). 
The average number for this area was found to be 
14.875· 
All stomachs were empty when examined. 
General observations 
Comparison of numerical and biological values 
of herring from the southern North Sea with 
those from the English Channel, shows a simila-
rity in composition of the populations present there 
during December 1956 and January 1957. 
Total Total 
Dec. Jan. 1956-57 1955-56 Dec.--Jan. 
4 10 4 
13 29 23 16 41 
195 114 157 155 149 
448 514 478 483 488 
278 314 295 302 286 
62 19 42 41 36 
1000 1.000 1000 IOOO 1000 
14.830 14.848 14.820 14.804 14.875 
0.8837 o.8292 o .8520 o.82o5 0.8624 
O.IC)20 0 .2728 0 .0893 0.0836 0.2244 
The difference between the average lengths 
observed in the two areas is 3 mm. only (251 mm. 
in the North Sea and 254 mm. in the Channel). 
The difference between the average weights is 
also very small, 4 g. (106 g. against no g.). 
The frequency of recently spawned herring 
maturity stages VII and VIII-II) differs hardly 
{f)659/00 and 947%0). In both areas, the 2 to 6-year-
old herring formed the majority (884 °/00 and 
863%0). In consequ ence the older year-classes were 
abnormally poorly represented. 
-zog-
% 
Herring 
Near N. Seas 
The vertebral average of the hen;ing in the two 
areas was also of the same vslue, s6.68 and s6.66 
Conclusions 
The results of the investigations tend to show:--· 
(r) that after spawning, the herring of the North 
Sea penetrated very deeply into the English 
Channel, where they probably mixed with the 
Channel herring populations; 
(2) that the majority of herring 6 and more years 
old were absent in the extreme south of the 
North Sea, through causes which are yet to 
be elucidated. 
It is presumed that these two facts may be held 
largely responsible for the poor results of the past 
herring season in this area. 
If these phenomena were to happen again next 
year, the success of the southern North Sea herring 
fishery in 1957- 58 may once again be highly 
endangered. · 
CH. Gnus 
30 
20 
10 
44 
43 
30 
20 
10 
44 
30 19SS 
20 
IO 45 
53 
so 000 
ooo 
000 
40 ooo 000 
ooo 
30 ooo 
ooo 
ooo 52 20 000 
000 
000 
10 000 
000 
so 
49 47 
ooo WZIJ+ +•• 
Figure I?· Biologica l scale of the full-herring concentra-
tions exploited by t he Belgian trawlers in 19s3-19s6. 
C. Baltic-Belt Seas 
YOUNG STAGES 
Larvae in the Kattegat and the Belt Sea 
The quantity of herring larvae was investigated 
in April by fishing with a ring-net at some few 
stations in the Belts and the southern Kattegat . 
No larvae of winter or spring spawning herring 
were caught. Atsome stations near the spawning 
places of the autumn spawning herring, north and 
east of Lres0 in the northern Kattegat, great 
quantities of larvae were obtained in November. 
AA. J. c. JENSEN 


The Belgian herring fisheries in 1956-1957 (30 July 1956 - 19 January 1957)

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