.:1.
International Commission
for 'the
Northwest Atlantic Fisheries
19 SO
,
\.
.'
.,:
~; ~ ;,
1970
"
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RESTRICTED
Seria l No.23 79
(D.c.3 )
ICNAF Res.D oc.70 /47
ANN:UAL MEETING - JUNE 1970
Depth Distr ibutio n of "Beak ed" R.edfi sh (Seba etes mente
Ua Travi n) on Flemi sh Cap Bank
by
V.A, Chekh ova
PtliRO, Murma nsk
A.
lon~'I;• .I.'a
1Dte nsi"f 'e fishi Dg fOI!" beak ed" I!edf ish on
the Kopy tov,R ozen garte n,An tOD D01!D and Flem ish Cap, bank
s did
not affe cted the age- size comp ositi on of I!edf ish (Soro
ld.n,
1963 ;SUl 'kova ,195 7;Ko nstan tinov ,196 6). 'fhe age- size comp
osition of the fishi ng put of the "bea kedlt 1!ed fish stoc k
is
stab le even i f the. fall in the tota l eatch ,mea n catc h
per
traw ling hOUl ',redU Gtion in the fishi ng pe1!1od or a full
cess ation of the fish ery is appa rent. The pape rs by Surk
ova
(196 2) and Rich tel! (196 5) sugg est a prob able tend ency
in rejuve natio n of the "bea ked" redf ish stoc k on the Flem ish
Cap
. Bank unde l!the influ ence of fishe l!y.B ut the decl! ease
in the
aver age age is I!ath el! attl! ibute d to dis~ocation of the
fish ing flee t to smal lel! dept hs Ol! to chan ge of the seaso n
and
uea of the fishe 1!y (Sav vat1m sky,1 965;C hekh ova,1 964) .
'fhe ques tion on distr ibut ion of "bea ked" Ndf ish acco l!ding to dept hs on the· cont inen tal slope · of the Nort h Newf
ound ····land Bank was discu ssed earli el! (Sido l!enk o, 1967 ). It
was
state d for the southe1!D Flem ish Cap Bank that in A.ugu
st the
mean leag th of redf ish male s and fema les was dscl! easin
g
(S.VTat~,196') with dept~
'fhe aim of tile papel ! pr0p 0ee4 is to show the pecu liuit
ies
of diffe l!en cesi n ag....1z. ca.p osit1 on of "bea ked" ·l!ed
f1sh
accol !d1ng to dept hs and seasODS.
'fhe yeal! ly cycl e of matUl'e Ndf ish bl!ea ks down into the
perio ds:
A2
- 2 -
1. Extrusion of larvae and beginning of the summer feed:i;ng - lIarch-June.
2. Summer fattening and copulation - July-october.
}. Wintering and maturation of females - November-February.
lIarch-June
Redtish males do not make any considerable migrations.
The specimens of }}-}5 em in length at an age of 12-14 years
predominate at all the depths from 201 to 700 m (Fig.1 ,2).
The changes are clearer expressed in the length composition of f'emales. Large female specimens of }7-'9 Cm long prevail at Ii depth of 201-}OO m. Though the main length
of
}4-}?
em
gro~
remains in the }O1-7OO m layer,there increases a
propotion of female.' specimens of }7 em long deeper than 501 m;
as a consiJquence of tl11s increases the average length along
with the bcrease in depth from 501 m (Table 1). Ohanges in
age composition according to depths are in agreement with those
in length composition. The propotion of male specimens at en
age of
1~14
years and female ones at an age of 14-15 years
increases'deeper than 501 m.
July-october
In: the period of the summer fattening an even distribution of redfish according to depths from }01 to 600 m is obse.rved (Table 1). The age-size composition is almost the same
.~ all the depths,though elder female specimens of larger
sizes keep to a depth of 201-,00 m (Fig~1,2). The number
of large redfishes of elder age increases deeper than 601 m.
In August,when a migration of redfish from large depths
toamalier ones continued,there was worked a series of trawl"
ings st.t>ictly keeping to depths of 201-}00 m,}01-400 m,401500 m,.501-600 m. These trawlings showed that a predominating
age and size of male and female specimens at a depth of }01600 mW$e decreaSing with depth.
Thns,July-october
may
be characterized on the whole as
a pedod of a relative stabili"t7 in the age-size composition
A3
- 3 -
at all the depths down to 600 m (600 m inclusive). The migration of redfish and differentiation of the age-size composition is still possible in the beginning of the period,the
fact we observed in August and that was noted by Savvat1msky
(1963). The predominating length and age of redfish changes
from the depth of 601 m: the deeper waters the larger redfish.
November-February
During this season the relationship between the redfish
length,their age and depth is most clearly marked (Fig.1,2)
and becomes apparent from a depth of 4Cn m.
When analySing the distribution of redfish in every season we made sure that a relationship between length,age and
the depth of inhabiting of "beaked" redfish on the Flemish
Cap Bank is distinctly marked throughout the year. In JulyOctober it is apparent deeper than 601 m and in NovemberJune deeper than 401 m.
It is evident from Table 1 that the greatest number of
trawling hours was worked in March-June at a depth of 501-600 m,
in July-october at a depth of 401-500 m,in November-February
at a depth of 301-400 m. In November-February they fished for
cod at a depth of 201-300 m,redfish were only met with in the
by-catch. At all the depths mentioned redfish males with the
mean length of 32.9-33.3 cm and female ones with the mean
length of 34.7-34.9 cm were caught.
Thus,throughout the year redfish of 33-35 cm long were
moving along the slope of the bank. The commercial fleet followed their seasonal movement changing the depth of trawling,and
therefore fDr the space of the year the fleet fished for redfish of the same size. This explains to some extent why after
some years of heavy exploitation of the fishing banks the redfish catches were reducing while the age-size composition was
stable.
A4
\.\1
U1
,.
:
:
:
•
• hour, • maJ.es
:centner:
•
: hours :
:o-r
.•
:
July-October
Mean
length,
in em
males .. feaa..lea
: Novembe1'-February
.
.
• •
:Number :Catch
: Mean length, :Number :Catch :
:01' tra": per
: in em
:of trawl~per
:
.ling: trawl- :
:illg
:trawl -:
:hours : ; n D ' ·•
e.
hours .. ~
~"''''
•.• • --0
feules
• hour, : males female,
:hour,.
:
:centner •
• • centner·
:Humber : Catch:
traw-! per
: Mean length,
: lillg : traw.l.-: in em
-1-~
llarch-June
25
25
3042
103
601-700
35,1
36",3
25
5626
lI501
189
2668
18
16
6
8
15
38,7
32,7
33,1
33,6
35,6
32,9
38,8
35,1
38,0
34,3
34,7
36,4
1052
63
1258
879
4004
23
II
13
II
6
40,4 40,4
35,2 35,3
33,3 34,9
34,2 36,7
35,2 37,7
35,6 38,0
----~------------------------------------------------
701-800
22
35,8
34,9
33,8
32,9
33,3
34,3
21
401-500
501-600
37,2
33,8
9
61
701
1843
201-300
301-400
••
••
••
••
••
••
••
••
••
••
••
••
-----------------------------------------------------
m
Depth
·:•
------~---------------~---------------~---------------
Fishery and the mean length of SeB,bastes mentella Travin at different
depths of the Flemish Cap Bank
Table 1
...
- 5 -
References
1. RICHTER,V.A. Some problems on Sebastes mentella Travin
fishery in the Newfoundland area. Rybnoye khozyaist\-,:-,
No.5,7,1965.
2. SAVVATIMSKY,P.I. The materials on distribution of redfish
(Sebastes mentella) in the North-West Atlantic. ICNAF,
Ann. meet.,June 1963,doc.59.
3. SIDORENKO,I.N. Distribution of "beaked" redfish (Sebastes
mentella Travin) at different depths on the North Newfoundland Bank. Materialy sessii Uchenogo Soveta PINHO
po rezultatam issledovaniy v 1965 godu,vyp.8,Murmansk,
1967.
4. SOROKIN,V.P. On the Influence of Fishery upon the Structure
of the Sebastes marinus and Sebastes mentella 'l'ravin
Populations. Materialy rybokhozyaistvennych issleu(WRII.Ly
Severnogo basseina. No.1,Murmansk,1963.
5. SURKOVA,E.I. Sex and age composition of the redfish (Sebastes mentella Travin) of the Kopytov area. Trudy PINHO,
vyp.10,1957.
6. SURKOVA,E.I. Size and age composition of redfish (Sebastes
mentella Travin) in the
Nortb~West
Atlantic. Sovetskie
rybokhozyaistvennye issledovaniya v Severo-Zapadnoy
chasti Atlanticheskogo okeana. Moskva,1962.
7. CHEKHOVA,V.A. Effect of the fishing upon the size and age
composition of redfish in the Flemish Cap area. Materialy sessii Uchenogo Soveta PINRO po rezultatam issledovaniy v 1962-1963. Murmansk,1964.
8. KONSTANTINOV,K.G. and NOSKOV,A.S. USSR Research Report,
1966. Internat. Commisso Nordwest Atlant. Fish,Redbook
1967,part II,Dartmouth,1967.
A6
....
,.
\
\
--
em
35
I
.. 0
\
\
,,
40
\\
,,'," ,
"-
45 em
10
a
5
10
0
5
10
25
30
601-700
!is
~
\
,
'-
---
~+
It
40
0
5
10
0
5
10
601-?00
25
30
701-800
45 em
0
5
10
0
5
10
0
0
10
0
5
10
0
,,,\
,-,
401-500
5
10
D
5
10
5
501-600
401-500
5
10
0
5
10
0
em
I
0
301- 400
25
201-300
0
10
0
5
'Yo
1
5
45
45
""-------
40
,
"-,
1,
I'
I I ',
I
,
I
%
5
301-400
25
201-300
JULY - OCTOBER
5
10
0
5
to
0/0
MAROH - JUNE
25
3
701-800
601-700
501-600
25
201-300
\
,\
\
\
...
'-
em
em
-'.. \
\
,
\
40
'--,\
\
,,.....
45
NOVEMBER - FEBR.UARY
Fig. l.
Length composition
of "beaked" redfish OIl Flemish
Cap Bank in some
periods.
'"
CO
,.
0
10
20
30
0
10
20
0
10
.,
.,
9
9
U
U
is
13
17
17
21
20
10
7.0
19
D-~~
21
0
10
20
501-601 fO
401-500
19
I-eft
15
IS
10
lO
301-400
20
%
10
20
%
0
MARCH-JUNE
?
'1
9
9
11
13
15
15
17
17
JULY- OOTOBER
19
21
601-700
SOl-600
401-500
301-400
201-300
%
.,
9
11
13
15
15
1'1
17
NOVEMBER- FEBRtlARY
2t
19
21
60~-700
401-500
301-400
f9
201-300
a.~
Fig. 2.
periods.
Bank in some
Age composition of
"beaked" redfish
on the Flemish Cap
"