7
C. lVI. 1962
International Council for the
Distant Northern Seas Committee
Exploration of the Sea.
No. 34
gr~~.idk~,to~
8Bwnote,~e,t
Norwegian
~~pelin
investigations.
by
Dag M0ller and Steinar 016en,
Institute of Marine Research, Bergen.
At the Finnmark coast mass spawning of capelin occur fairly regularly. In most years the first spawning runs are observed in February/
March, and they are usually followed by fish in abundance, especially
cod, and by birds and whales. This event marks the start of the traditional Finnmark spring cod fisheries, but the capelin themselves
have also regularly been fished by Norwegian fishermen.
There are scattered information about the capelin fishery as far
back as 1734. Until 1916 when capelin was first used for reduction
purposes, it was a very small fishery for bait only, and yearly landings remained in the main fairly low until the post-war period.
The modern capelin fishery has during the last decade developed
very rapidly and reached a record of more than 220,000 tons in the
1961 season (Fig. 1), The chief method of fishing is purse seining
which accounts for more than 95% of the catch.
Material and methods.
In 1960 the Institute of Marine Research, Bergen, started a program
of capelin investigations. Research vessel surveys were conducted
in September 1960 and August 1961 to the Barents Sea and during the
spawning runs in February/March 1961 and February/April 1962.
The work included asdic and echo-sounder surveys, sampling with
mid-water trawls and hydrographic observations. During the 1961
capelin season an extensive sampling program of the commercial catches landed at the reduction factories was carried out (Table 1).
- 2 Total length in mm was measured to the tip of the lower lobe of the
caudal fin in "natural position". The figures given are for fresh
material. When frozen material was used a conversion factor was
applied to give the corresponding "fresh"'length.
Age determinations are .f'rom otoliths, which appear to be fairly easy
to read, except that difficulties
sometimes arise with regard to the
interpretation of the very first growth zones.
Detailed catch statistics for the most recent years are fairly complete, and yearly records of time of arrival of the first spawning
runs, and to some extent also locality, are available since 1868.
Distribution, age and length in September 1960.
During the 1960 September cruise special interest was paid to the
frontier area between cold and warm ,,,aters, i. e. the area bet,,,een
the 0
0
_
0
and 4 -isothermes in 50 m.
The capelin appeared to have a westerly distribution (Fig. 2).
Capelin larvae (O-group) were taken in abundance near Hope Island
and in smaller numbers further east on the Central Bank. On the
Novaya Zemlya grounds and in the south-western Barents Sea no capelin
larvae were taken. Concentrations of older age-groups were located
0
in areas of great horizontal temperature gradients between 75 50'
and 77°20'N, and between 26
0
0
and 41 E, particularly NE of Hope Island.
Relative to the 1- and J-yearolds, the II-group was poorly respresented (Fig. J).
The condition of the capelin taken in September 1960 was very good
and they were feeding heavily on Euphasiids.
Distribution, age and length in August 1961.
This year the invenstigations were carried out simultaneously with
three vessels, and the surveyed area and the sampling program was
considerably extended compared with the previous year.
Owing to the loss of fine-meshed gear for catching capelin larvae
insufficient data were obtained to show the distribution of the
O-group.
- 3 The older age groups appeared to be very sparsely distributed over
large areas from about 75°N and northwards (Fig. 4), and no clear,
simple relationship between distribution and temperature could be
established. Only in the north-western areas, near the ice edge
more dense concentrations were occasionally located.
The relative abundance of the various
age groups seemed to be
related to the latitude. The I- and II-groups dominated in the
southern areas of distribution, and the older capelin, as well as the
most fast growing ones of the younger age groups were more northerly
distributed (Fig. 5 and Table 2).
In samples of large capelin many females contained. large residual
eggs in the ovaries, thus giving evidence of survival from a previous spawning.
Contrary to the situation in 1960 the condition of the capelin was
poor with a low fat content, and most stomacks investigated contained little or no food.
Time and distribution of spawning at the Finnmark coast
since~,§68..~_
In fig. 6 are plotted for each year since 1868 the date of first
arrival of the spawning runs at the East- and vlest-Finmnark coasts
respectively. These are based on old records and reports of the
appearance of the capelin, recorded because of their significance
in connection with the spring cod fisheries.
The capelin have regularly visited the Norwegian coast, except for
the five-year period 1938 to
1942, and again this present spring,
when they failed to appear at the regular spawning grounds. The time
of arrival, and probably also the magnitude of the spa,vning stock,
have fluctuated greatly, but in most years the first schoolshave
reached inshore waters in February or March. It appears that a few
years of early or late arrival usually follow in succession, but
with no regular periodisity.
Early arrival seenlS to be associated with a westerly distribution
of the spawning capelin, and vice versa. As a rule, though, the first
schools usually appear
all
the East-Finrunark grounds, and this is the
area from which they latest disappear at the end of the season.
- 4 The spawning runs in 1961 .•
During the 1961 season there were three distinctiy separated spawning runs at the Finnmark coast (Fig. 7). The first schools struck
land on February 17. and were gradually distributed along the coast
west of North Cape.
During the days of February 24. to 26. a new influx was located off
the coast of East Finnmark. The first schools reached inshore waters
in the beginning of March at Vard0, and somewhat later further west
on the Varanger Peninsula. These capelin were rapidly distributed
along the entire Finnmark coast and led to a second peak in the fishery of the western districts.
The third spawning run came in the beginning of April. It was limited
to the coast of the northern Varanger Peninsula and lasted for two to
three weeks.
The spawning stock in 1961 was mainly made up of 4-yearold fish
(1957-yearclass), and the mean length was high, nearly 2 cm higher
than those for 1959 and 1960 reported by Prokhorov (1960). There
were only slight differences in age and length distribution between
the two first spa1ming runs, but the capelin of third spawning run
were somewhat smaller and contained a significant element of J-yearold females (22.6
%of
the females).
During the season there was a profound change in the sex proportion.
In the middle of February males and females were taken in about equal
numbers. In late February and during the first half of Harch the females dominated, but thereafter they were rapidly decreasing in number, and at the end of the season the males were in great majority
(Fig. 8).
The capelin taken during the 1961 season were in a very good condition.
The fat content was as high as 12
to 4 - 6
%by
%in
the first catches and decreased
the end of the season, as against around 2
% in
pre-
vious years.
The 1962 season.
In February and March 1962 capelin were occasionally found in the
- .5 stomack contents of cod at various places along the Finnmark coast,
and this is a common experience some time in advance of the first
main spawning run. This year, however,larger concentrations of cape1in were never observed near the Norwegian coast, in spite of continuous surveying with two research vessels from the beginning of
February to the middle of April.
The investigations were first started in the south-western part of
the Barents Sea, whereafter the south-eastern part was covered. The
first of March concentrations of cape1in were located over a fairly
wide area in the Goose Bank - Prestneset area. During the next four
weeks there was a slow movement in south-westerly direction and at
the same time a disintegration and dispersal of the schools (Fig. 9).
Some schools reached as far west as the Ki1din Bank, and around the
first of April there was apparently cape1in spmming at and off the
coast in the Ki1din - Cape Teriberski area. Off the coast in this
area spent cape1in were found in the beginning of April, and in the
middle of May masses of dead cape1in were observed afloat. One might
however raise the question, whether the cape1in in 1962 to a large
extent spawned farther off the coast on the banks of the southeastern Barents Sea.
Only a few samples of the 1962 spawning stock is available, mainly
of the concentrations located in the beginning of March. They show
a majority of 4-yearo1ds, but with .5-yearo1ds (19.57-yearc1ass) amounting to as much as 30%. In spite of the high mean age, the mean
length was smaller than in 1961, and the cape1in were in poor condi tion with a i'a t con tent in the beginning of March of 6 to 7
% only.
Discussion.
Paired with Soviet observations for 1959 and 1960 (Prokhorov 1960)
these investigations show age and length distributions of the cape1in spawning stock for four consecutive years (Fig. 10). These
seem to indicate that cape1in spawn at ages from two to six, but
mainly as three- and four-yearolds. Considerable fluctuations in
relative yearc1ass strength are evident and may effect the magnitude
of the spawning stock several seasons in succession. Thus, the rich
19.57-yearc1ass which yielded about 95
% of
the record catch in 1961,
also contributed substantially to the good fishing in 1960. Similarly, the 1956 yearc1ass was the main contributer to the spawning stock
- 6 in 1959 and in 1960, This does not necessarily postulate a high rate
of repeated spawning, and is probably to a great extent effected by
gradual maturing of a yearclass at different ages.
It is evident from the regular observations of large masses of dead
capelin after the spawning season and failure to find specimens older
than 6 years of age in the capelin population, that postspawning
mortality is very high, at least from age four and onwards.
Survival after spawning is demonstrated by the observation in August
1961 in the northern Barents Sea of recovering spent females maturing
for a second time, and by Soviet observations reported by Prokhorov
(1960). No data exist however, to indicate the relative magnitude of
post-spawning survival in capelin, and quite likely great yearly
fluctuations would occur, as the survival is likely to be effected
by variations in age distribution and condition of the spawning capelint
The sex proportion of the various age groups show a majority of females in the youngest age groups, but more males than females from
age five and six. This indicates a slightly lower mean age at sexual
maturity for the females and possibly also a higher survival rate for
the males.
In 1961 the larger and older fish arrived first on the spawning grounds.
This is probably a general feature for the capelin (Templeman, 1948)
as well as for other species of spawning fish. \rIe have previously
mentioned that an early spawning run seems to be associated with a
westerly distribution, and it is conceivable that the size and age
distribution of the spawning stock may have some bearing on the time
and location of spawning, as well as environmental conditions during
maturing and spawning season.
The geographical distribution of spawning in 1962 was entirely different froL1 that of the previous year. One might have expected that this
to some extent, at least, was related to a 'change in hydrographic
conditions. A comparison between the temperature distribution in these
two years, however,
(Fig. 11) does not reveal a very great difference.
In 1962 the waters at the Finnmark coast and in adjacent areas were
slightly warmer than at the same time in 1961, but not a great deal.
Consequently, also the spawning temperature for the capelin in 1962
differed much from the conditions of 1961. It seems therefore just to
- 7 conclude that the range of temperature for oape1in spawning in the
Barents Sea is wide, as has been reported for Newfoundland waters
by Temp1eman (1948), and the choice of spawning locality is probably less effected by
tempe~ature
than by other faotors.
SummaIT..!..
The modern Norwegian cape1in fishery for reduction in the post-war
period has developed very rapidly fror.1 less than 5,000 tons per year
until 1950, to more than 220,000 tons taken in 1961. The chief method
of fishing is purse seining, and the number of vessels engaged in
this fishery increaeedfrom 43 in 1951 to 168 in 1961.
The Institute of Marine Research, Bergen, started a program of cape1in investigations in 1960. Data of distribution, age and length for
all age groups were collected in September 1960 and August 1961 in the
northern and eastern Barents Sea, and for the spawning stock in winter
and spring 1961 and 1962 in coastal and adjacent waters. An extensive
sampling program of the commercial landings was carried out during
the 1961 season.
In Septer.1ber 1960 cape1in both larvae and older age-groups appeared
to have a westerly distribution.
In general the survey indicated that cape1in of one year and older
were accumulated in areas of large horizontal ter.1perature gradients.
In August 1961 all sizes of cape1in seemed to be very sparsely distrio
buted over large areas frOI~ about 75 N and northwards, and contrary
to the situation in September 1960 no clear, simple relationship
between distribution and temperature oou1d be established.
Th()re was a clear trend of an increase in size and age with increasing
latitude, and this was parallelled with a similar increase in mean
size of each age group, i. e. the largest and most fastgrowing fish
were distributed farthest to the north.
Annual records since 1868 show that the cape1in have regularly
visited the Norwegian ooast, except for the five-year period 1938 to
1942, and again this present spring. The time of arrival at the coast
of the first cape1in schools, and probably also the magnitude of the
spawning stock, have fluctuated very greatly, but in most years the
- 8 first schools have reached inshore waters in February or March. It
appears that early arrival is associated with a westerly distribution
of the spawning capelin and vice versa, and a few years of early or
late arrival usually follow in succession, but with no regular periodicity.
During the 1961 season there were three distinctly separated spawning
runs at the Finnmark coast. The first schools struck land on February
17. and were gradually distributed along the coast west of North Cape.
The next influx came to the coast of the Varanger Peninsula during the
first days of March, and thereafter moved westwards. Finally, in April
there was a new invasion limited to the coast of the northern Varanger
Peninsula.
There were only slight differences in age and length composition between the two first spawning runs with 4-yearolds averaging 94% of the
total. The capelin of the third run were somewhat smaller and contained
a significant element of J-yearold females (22.6% of the females).
During the season there was a profound change in the sex proportion.
In February males and females were taken in about equal numbers. In
March the females dominated, but at the end of the season the males
were in great majority.
In 1962 the capelin schools were first observed in the beginning of
March in the Goose Bank - Prestneset area. During the next four weeks
there was a slow movement in south-westerly direction and at the same
time a disintegration and dispersal of the schools. Some spawning
apparently took place at and off the coast in the Kildin - Cape Teriberski area where spent capelin were found in the beginning of April
and in the middle of May masses of dead fish were observed afloat. No
schools of capelin were ever observed west of the Kildin Bank.
Paired with Soviet observations in 1959 and 1960 (Prokhorov 1960)
these investigations seem to indicate that fluctuations in relative
yearclass strength may significantly effect the magnitude of the spawning stock several seasons in succession. This does not necessarily
postulate a high rate of repeated spawning, and is probably to a great
extent effected by partly maturing of a yearclass at different ages.
It is evident that at least from age four postspawning mortality is
extremely high, and no specimen older than 6 years of age was ever
- 9 -
found. The sex proportions for the various age groups might indicate
a slightly lower mean age at sexual maturity for the females and a
higher survival rate for the males.
The detailed studies of the 1961 spawning runs showed that also in
capelin the larger and older fish arrive first at the spawning grounds.
Considering that early arrival seems to be linked with a westerly
distribution it is conceivable that the size and age distribution of
the spawning stock may have some bearing on the time and location of
spawning, as well as environmental conditions before and during the
spawning
season~
The range of temperature for capelin spawning in the Barents Sea is
wide, and the choice of spawning locality is probably less effected
by temperature than by other factors.
References.
Prokhorov, V.
s.
1960. Post-spawning survival of the Barents Sea
capelin. Int. Count Exp. of the Sea, C.M.1960,
no. 165.
Templeman, W. 1948.
The life history of the capelin in Newfoundland
waters. Newfoundland Govt. Bi£1. Sta., Res.
Bull., no. 17.
- 10 Table 1.
Material capelin 1960 - 1962.
Investigation
Length-measurements
1 747
9 824
Summer 1960
Winter 1961
Summer 1961
Winter 1962
Total
Table 2.
Otolith-readings
145
2 207
949
7 775
2 781
495
22 127
3 796
Mean sizes in different localities summer 1961.
Year class
1961
1960
1958
I
1959
II
A.Hope Island W
10.16
12.55
B.Rope Island E
11 .63
12.45
C.Central Bank NE
11.83
12.45
D.Great Bank SW
12.05
13.1 ;2
14.96
E.Hope Island N
12.45
14. 31
15.80
16.86
NW
13.18
14.49
16.65
18.37
11 .88
13.23
15.80
17.62
Locality
Age group
F.Great~nk
Average
0
III
1957
IV
NO. OF ---=-r.=:=~
I
I
I
I
200
I
I
150
,,
,,
I
I
,,,
,
I
I
,""
"
..
I'
1 '
,
100
1
1
1
'I
I
I
I
I
50
I
I
1
1
tI
tI
.
1946
Fig. 1.
48
.".
-
-'"
.,
",-
':""'-
50
""
52
""
""
"
54
56
58
60
62
Catch of' capelin in Norwegian waters 1946 - 1961.
Number of' vessels in Norwegian capelin f'isheries
1951 - 1961.
.;;;;
,......
,....... ...., 30'
25'
20'
--
........35' ..-.
40'
.,..".......,
-. ...JJ,' -...
....... L~ -..Jl-,78
1
f
HOPE ISLAND
I
+
7ff
+
et0
+~
••
++
+
BEAR I SLANO
0
0
'BcP00 -
0
3-:t:::;-
+
-I-
?tj
+
++
-I-
0
-I-
-I-
++
'*
-I-
7fl
: + NEGATIVE
Ft" • .2..
Oapelin distribution September - Ootober 1960 •
.hl /\
30
,
'"
lOO
50
-
20
10
,....
-
,
'"
B
-
A
n
~'fLl
8
'I.
30
50
C
10
-
n
D
I
Fig. 3.
20
1I
m
~~
C
~
D
~I
10
15
20 cm
Age and length distributions September
1960.
A.Novaya Semlya
C.• Central Bank NW
B.Central Bank SE
D.Hope Island E
I
7f-
73~
74~
75'
'i1
o
--_ .....==. ::::.-0-.---... _
.... --- ... _-.
C-ZEZ·<·/:::·:·::·::.<::. .: ".
BEAR ISLAND
TRAWLSTATlON
)
t AOO. 1961
')
4ft
.:...0:-
5rt
NOVAJA.. ZEMLYA
4~
... :: ':::::0::-- : : ..
.:.:.::=::::::.-=0=-.... ::--0-
Capel.in distribution August 1961.
o
"TORRIS"
"G. O. SARS"
"ANNA G"
"~:':-:::::-==o
HOPE
--
~:::==:.:.:..: ..-:--:::.:
I. ..
0===.:.-:: ____ ......:. __ _
ISlAND - - c r - - " ' = = , .. "'_::::. __ ._. __
rig. 4.
J
Ti
78°
f>Vo
-0.-----
~
"/.
20~
11
'/.
10
20
30
"!.
10
20
30
"!.
10
20
30
30
Fi«_ , .
10
I
A
! \
15
20
F
E
D
c
8
A
cm
A.Hope Is1and W
C.Central Bank NE
E.Hope Island N
1961.
B.Hope Island E
D.Great Bank SW
F.Great Bank ~~
Age and l.ength distributions August
10
20
30
'I.
10
20
20
F
E
40
:r:Ii::m~
::i Dn~n
_60
D
C
B
::1 A
30j
L-__J-~~_L~~~____ "!.
so'j
'/'
20
40
sal
'I.
A
'f,
LLl.l----L.L.L_ _ _ _ _ "I.
J ~~
"/.
60
20
40
60
>-
et:
I \
/r\\
1870
"1/U
I I
I1
11
I I
I I
1 I
I I
'I
\ I
I
\
\
1\
\~
\\
80
85
\
'i
,
,
\
\
90
U
I
tI
11
I1
11
P \! I I
95
t
..
iI
: I I
\ I I I
~
~II"
.u
1900
\
\
\
\
\
!\~V
) \ !\
05
I
J
I'
(
.-
,,
I f
10
I
_I
-/
\ ~
I:
I
15
I
,
I
I
I
\
i
\
\...-1
\
LI
20
I;
1/
/',
I
'-
\
I \ "
I I 1\
I
I
/''
I
11
h
\',
~
LW'V
I
I
.
t\
25
30
35
1,0
0
Z
U')
f.
~
Z
z
0
U
<
W
ll..
...j
Z
~
~
:J:
w
Z
~
et:
0
W
(5
z
«
u
0
«
~
If)
1,5
Date of first arrival on the Norwegian coast of spawning capelin 1868 - 1961.
75
- - - WEST Ft NNMARK
\
A
\
- - EAST FINNMARK
\
\
\ "I
\ \!
!
I
I
I
Fig. 6.
:I:
~
--~I
<I
il
~
CD
I
~IJi\\f
~l
:\
~I
<
::l
z
V
1/
50
,
55
I[
,
If
I
I
I I
I
I
I
60
24- 26/2
Fig.
7.
21/3 -1/4
Capelin distribution FeGruary!April 1901.
I
16
18
Fig. 8.
I
20tSO
·1
4olso
60HO
80+20
T
olr-?l
U
I
%
22
24
26
0
28
0
2
~.
4
0
6
•
8
ro
.~
•
0
a
~
K
~
MARCH
•
m
n
~
~
• .,
-
.. .. • •
•
----------
~
e
Sex proportion of capelin during the spawning season 1961.
FEBRUARY
20
0
0
•
0
o
~
•
2
3.
4
.6.
•
8
.6.
APRil
6
.6.
- .. -
1. spawning run
• .6.
.6.
o
.2.
10
12
14
.6.
'O.O.IIARS·
1-5.3 18112
71'
70'
-~
ao'
40'
eo'
45'
"JOHAN HJORT"
IO...UI902
71'
...""
.!fit
70'
iF
l1'1B. ,.
i
•
Capelin distribution March/April 1962.
2
Fig. 10.
40~
20~
~1002
20
40
50
3
5
3,!f.
6
3~
t
10
20
~.
"
2G
~
10
20
-I
%~
30
10
12
,,
.'
14
16
18
20 22 cm
Age and 1ength distributiomof
spawningcape1in 1959 - 1962.
(For 1959 and 1960 reconstructed
from Prokhorov, 1960).
4
ff,
et
1960c:F ,...,!f.
to" 1961
20-;
4°1
-{
60-1
%j
20
!l-
20
40
lO~
30
60
as
.,.
%119S9c:r~
80-i
f
,.
Fig. 11.
...
"
7IT
-
•
..
:;r
'
\j \\
~
"
40'
1\'
.....\.~.........._
. . . .-.
:/
f l. .""
- :•
~
•
-,.
-----tttt
"-_·tIIt
-G.Q.s.,.-
Temperature distribution April.
1961 and March 1962.
30·
=="""11, '
'>.4
,
"f
• •
~
"
l'
~(
t~.
~ ,
, t"
{'
:
') \t'... ,
I'"
~72"
,