C M 1996/S:26
Theme Session S
International Council for the
Exploration ofthe Sea
Changes on horse mackerel (TrachurUs trachurus)'catch distribution'
in the Northeast Atlantic
by
Borges, M.F. I ; Silva, A. I ; Abaunza, P. 2; Eltink, A. 3; Lucio, P. 4; Walsh., M.
Casey, J. 7; Iversen, S.; Skagen, D. 8; Sanchez, F. 9
2
3
4
S
6
8
9
$ ;
Poulard, J.C. 6
Institute de Investiga~o das Pescas e do Mar, Avenida de Brasilia, 1400 Lisboa
Portugal
Instituto Espanol de Oceonografia, Centro Costero de La Coruiia. Apartido 130, 15080, La
Corufia, Spain
,
Netherlands Institute for Fisheries Research. RIVO, P.O. Box. 1970AB, Ijmuiden, the
Netherlands
lristitUto de Investigacion y Tecnologia para la Pesca, Oceonografia y Alimentacion, AZTI,
48395 Sukarrieta, Vizcaya, Basque CounUy, Spain
.
SOAFD Marine Laboratory, P.O. Box 101, Vietona Rd. Aberdeen ABI 8DB,Scotland. U.K.
IFREMER. Centre de Nantes. Rue de l'lle d' YeuBP 104944037 Nantes Cedex Ol,France
'.
MAFF Fisheries Laboratory Lowestoft, Suffolk NR33 OlIT, England
Institute of Marine Research. PoStboks 1870-Nordnes. 5204 Bergen, Nonmy
Institute Espanol de Oceonografia, Centro OceonogrcUico de Santander. Apto. 240 39080
Sanmnder, Spain
Abstract
•
The distributions of international commercial catch data were mapped by ICES rectangle and
qllarter from 1983-1994. These indicate a northward expansion ofhorse mackerel'distribution in
the Northeast Atlantic since 1987. The spatial variability of the yearclass aburidance of horse
mackerel over the European shelf and shelf edge is investigated using international bottom trawl
survey data. The aim is to detennine if the northWard expansion of horse mackerel distribution is
due to the extremely strong 1982 yearclass. How the changes in oceonographic conditions since
1989 may relate to the fish northward expansion is also discussed.
Keywords: Horse mackerei, Trachurus trachurus L, distribution ch3nges, shelf edge, Ncirtheast
Atlantic.
Introduction
The Western horse mackerel '\1ntering-spa,..ning and feeding migrations have been described by
Macer (1977), Eaton (1983) and Anon. (1991). NevertheIess, doubts persist about on what extent
adult horse mackerel of south Biscay and Iberian Peninsula are joining the adult massive
northward feeding migration.
,
Spa\',ning takes place along the shelf edge off the Iberia Peninsula, the Bay of Biscay and the
Celtic Sea, commencing earlier in the south (auturnn/,..inter) and progressing northwards In
spring/summer (Anon., 1993).
The nursery areas correspond to the continental shelves of the same regions. confined
southwards of 56 OO'N latitude. After spa\\ning the adults migrate northwards along the shelf
edge and come back south also along the shelfedge (Borges, et al. 1995).
Under SEFOS project a striking result came out for this species: a northward shift in the
distribution ofhorse mackerel in the last decade is evident from (Borges, et al. 1995) results.
The present paper investigates in detail if the northward expandion of the horse mackerel
distribution was due to the extremely strong 1982 yearc1ass.
Material and l\lethods
Horse mackerel commercial catch dab., was supplied by Portugal, Spain, France, Scotland, the
Netherlands and Norway by month and ICES rectangle in a common agreed format under the
SEFOS project for 1983, 1986, 1989, 1992, 1994. A database was build in Acess Windows
database management and the data exported through an application to be mapped by quarter and
ICES rectangle using MapviewerlWin software. The map ofthe Northeast Atlantic from 3600' 64 30' N. Latitude and 08 00' E - 18 OO'W Lorigitude was supplied by the Hydrographic
Institute, Lisbon, participant ofthe SEFOS project.
A database ofbottom trawl survey from the fourth quarter was also created in a common format
under the SEFOS project. Number of fish per hour by length c1ass and sampling station is
available from Portugal, Spain, France, Scotland, the Netherlands and Norway for the period
1990-1994. As non SEFOS participant England made available to the SEFOS project horse
mackerei survey data under a special contract.
•
Length distributions were converted to age distributions using the Portuguese, Spanish age length
keys, from the corresponded survey. The Netherlands supplied the age length ke)'s by area and
quarter from commercial sampling and these were applied to the survey data of each area survey
from France, the Netherlands, Scotland, England and Norway.
Abundance indices by sampling station by age group were computed and mapped.
Data on the central and southern North Sea was not considered under the present SEFOS
project
Results
Figure 1 presents the distribution of cominercial catches by quarter in 1989 which illustrates the
general pattern ofthe distribution of cominercial catches along the year.
In the first and second quarters the fishery takes place maily around the Iberian Peninsula, in the
Bay of Biscay, .in the English Channel and along the shelf edge of the Celtic Sea and west of
Ircland. In the third and fourth quarter the fishery takes place at northern latitudes and high
catches are taken along the shelf edge north of Ireland, west and north of Scotland and off the
Norwegian coast.
Figure 2 shows that a northward expansion of the fishery is evident in the period 1983-1992. The
areas west and north of Scotland and especially the shelf edge of Norway became the main
fishing grounds ofhorse mackerel in the second half ofthe year.
The Norwegian horse mackercl abundance indices from the bottom trawl surveys are available
from 1991 to 1994. These indicate that the horse mackerel arriving in the Norwegian area are
almost entirely from the 1982 yearc1ass.
2
•
The 1982 yearelass distribution over the European shelf during the fourth quarter is shown in
Figures 3-5, bottom trawl surveys. The 1982 yearelass distribution can be eompared as agegroup 10 in 1992, age group 11 in 1993, and age group 12 in 1994 survey data during the
fourth quarter.
Discussion
The northward expansion of horse maekerel distribution might be due to the 1982 extremely
strong yearelass. As fish get larger they earn swim faster. This might explain the inerease in time
ofthe horse maekerel catehes in the Norwegian Sea.
The fishery eommenced in the Norwegian Sea since 1987-1989. This huge 1982 yearclass bad to
find other productive sites to feed than the usual sites which is indicated by a redueed growth of
not only the 1982 yearclass, but also other yearclasses (Anon. 1993).
•
Changes in oeeonographie eonditions whieh were reported to oceur sinee 1989 in this area
(Anon. 1990) might also have stimulated the northward expansion ofhorse mackereI.
Investigations on the surface temperature anomalies during this period from satellite images are
planned to be done under the SEFOS projeet.
References
Anon., 1991. Report ofthe Working Group on the Assessment ofthe Stoeks of Sardine, Horse
Maekerel and Anchovy. ICES CM 19911Assess: 22, 138 p.
Anon., 1993. Report of the MackereVHorse Mackerel Egg Production Workshop. ICES CM
19931H:4, 142 p.
•
Borges, M.F., Silva, A., Porteiro, C., Abaunza, P., Lucio, P., Eltink, A., Walsh, M., Poulard,
1.C., Iversen, S., 1995. Distribution and Migration of Horse Mackerel. ICES CM 19951H: 18
Poster.
Eaton, D.R., 1983. Scad in the North-east AtIantic. Laboratory Leaflet MAFF Directorate
Lowestoft 56, 20 p.
Macer, C.T. 1977. Some aspeets ofthe biology ofthe horse mackerel (Trachurus trachurus L) in
waters around Britain. J. Fish Bio!., 10: 51-62.
3
.
.
~,
eo
8
se
5
I
~,-'
,--'
-
.
5
,,
5
,,
5
rli...f
10• •
10• •
48
4
1_. QUARTeR
2nd ClUAATEF
48
4
44
-
....
•
4
4
, ,
4
38
3e
le
,.
'oll
'2
10
a
e
..
2
0
2
e
4
w_es
a
1&
,.
'4
12
'Olle
:z
..
__ es
:z
0
4
8
8
LCNGlTUCE
LC» ..... ca I"T''-' c::> I!S
8
8
.
"'
5
"""-
..
w
o
•
-.
s
5
5
:J
!:
5
5
1 ....
1 •••
4
..... QUARTEFl
3rd QUAATI!R
4
4
4
4
0 . . 10
10" '00
4
4
'00"
~ooo
1000_ .0000
,e ,.
''2
'0
e
.-
LONGlnJoe
202
w_oe
4
e
18
te
...
12
10
a
e
..
LONQlnJOe
Figure 1 - Distribution of commercial catches by quarter in 1989.
__ oe
202
e
----~~----
•• l,
50
<>
<>
,
-
"
52
rf'
eo
, ,
,
...
~
50
.....
~
I-.J~
62
~
'
,
I
,
..
50
...
""
,..~
.....
'rft}
..J.
-
,
,,
~
I
~
.. ,~
U
..
..
••
.
••
.
. .
",
usa
··'lo"_
~ QUA"TIi"
,
,
..
,
,.r-
f!
.
.;
J
t'l)
*
.:;:r: 7
,,"
,',
,
,g
,
"
50
"
.... QUAItTIiIt
-
,
......
;......
~
0
"
,
"
0
,
••
,
••
,
,.:?;....
~
oe
"
50
"'
..
..
,
,
-
"
~
W
Q
..
-
.ü
--
,
100
,
5.
,
.ü
/'
----------
,.
14
"
'2
'0
•
•
•
LONGlT\JOe
202
w_C
• •
,.
I
,.
.
,
,
.
14
12
,
",
..
'0
.•
•
LONGlT\JOE
.0.
• •
w_c
...
I~
82
eo
..
.
,
•
-
,'--
I
~.
54
,
~
52
C
5.
[.-
.,~
W
:J
t-
t=
~
••
,
.
•
..
,
,.
u
12,Q
•
LONGl'nJOE
Figura 2 - DisbibUtion of commercial catches in
un
,
.tto QUAItTIiIt
~~
'
,
,
,
I
..
,<
,
Uitl<n
.,
"
ma
h'
~
•
LONGlTUOE
I
CJ
I
10001010000 , I
•
1000010100000
• _c •
0
the 4th quarter of 1983,1986,1989 and 1992.
5
I
I
~ 10tollXl
10010 ~ooo
,'
•• ••
!
001010
-
,
. •• ••
oe
•
-
.'
,
••
...
.A= ~~tJ
~
"
' ~" '
I
•
,.
"'-'-'
.tto QUAItTIi"
••
..
..
" ..
~
,
..
'~.
,
,
,
•
i
62
60
(
58~
•
-w
o
z
-
.::J
-
~
-!
-
46 ~-t--+--+-t-t-+--I--+-t--+-l--l--:::~li:::..i.
~ . . ,.
.~.
.'
"~",;,,
-
44 t--+-+--+--+-l-+-I--I.
1
\
r'
1
tI
Unit°
[3
o to 10
B
10 to 100
~-
100 to 1000
I-
'.
•
W"",
12 10
8
6
4
I--
, ,
2. 0
2
LONGITUDE w-E
I
4
I
-,
6
~
,
8
Figure 3.- Distribution of the 1982 yearclass at age 10, during the fourth quarter 1992, fram battam
trawl surveys.
6
•
•
--z
w
Cl
.-
:J
~
...J
I I
46 I-!r--+--+-+---r-:--+--+-+--+--I-I--f~~-+--+-~;J
I I
D..
-
44
~~-
::
I
Ir
42
I
I
I
40
I
38
111
I
I
(,
I
'
I
I
I
1
I
I
)\
I
(
1·\ L,
I
o
o
1)1
i
I
I
I
I
..........
,
I
L&
I
,
I
'-
~
3~8 16 14 12 10 8
J/
l..
.&-
Oto10
~
•
10to 100
'-
•
100to 1000
-
~~=b:;p+==h;J~~~
1\ "'-,Fr,....J. J(
-
l-,---r-=...---..........---ri"'i
J?"'",
6 4
2 0 2
LONGITUDE w-E
Figure 4.-
lj
Unit.
I
4
,
6
,
8
Distribution of the 1982 yearclass at age 11, during the fourth quarter 1993, from bettem
trawl surveys.
7
•
64
_
T
,
J
j
.,- ..s-+-+/-:rl--+--+4z-+-+-+-+--I--l--I--+--J--+--J--+--+--PrJ-+-+--.1
~!~
V'f'\
-;'_
\
I
\
r
CI-
62
-......
-1::1"
--...
~
I-: "
--/ ,--'~'r-S
V
~~
-.,j
-
\....
1I
C>
<..,
l
/
.../1
J.;.;.A--~
V
(i'----' (
/_
\
I
•~
tx'
~~ ~_
-.:;-
.I_~
11
60
r
(
58J
•
-
Z
-.W
-
::J
I-
-
o
~
...J
;~"'"
"
~
;;
)
I
I
I
r
3
98
Figure 5.-
Unit:
1/(
40
38
)\(
,
42
}\
I
I
I
I
I
I
I
I
I
.,
T
"]
10 to 100
-
100 to 1000
I A
I I
1&
10 ,
I
16 14
o to 10
I
12 10
I
8
6
4
2
0
2
LONGITUDE w-E
4
6
I-
I
8
Distribution of the 1982 yearclass at age 12, during the fourth quarter 1994, from bottom
trawl surveys.
8
•