Fróðskaparrit - 01.01.2005, Side 123

MERKINGARROYNDIR VIÐ FØROYSKUM TOSKI 1952-1965
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5. Táning (1940) demonstrates convinc-
ingly the existence of the westward migra-
tion, probably because Faroese fishermen
at that time claimed that the fish moved
towards the east after spawning. Thus,
cod disperse both eastwards and west-
wards from “Norðhavið” after spawning
and eventually all over the Faroe Plateau
(Táning, 1940). These findings are con-
firmed by taggings on the spawning area
“Norðhavið” in March 2000 (unpubl.).
The results from the taggings on the
western spawning area “Vágahavið” rep-
i'esent new knowledge, because no tagging
had been performed there previously. They
showed that cod spawning in “Vágahavið”
in March were dispersed in the south-
western part of Faroe Plateau other times
of the year. These findings are confirmed
by taggings in March 2004 (unpubl.).
The duration of the spawning migration
only lasted a few weeks. It is not surpris-
ing because the distance to (or from) the
spawning areas is very short (ranges from
zero to 150 nautical miles, but is typically
30 nautical miles). The typical minimum
swimming speed of cod migrating from
the Icelandic spawning areas has been esti-
mated to 3-8 nautical miles per day (Jóns-
son, 1996). Assuming a similar swimming
speed for Faroese cod, the duration of
the spawning migration to (or from) the
spawning areas might be between zero and
50 days, but should more typically be be-
tween 4 and 10 days.
The location of the spawning areas
“Norðhavið” and “Vágahavið” may not
be constant (Jákupsstovu and Reinert,
1994) The spawning area “Norðhavið”
seems to have been more westerly dis-
tributed during 1994-2004 (ICES, 2004)
than in the 1930s (Táning, 1940) and in
the present tagging study (Figure 12). The
spawning area “Vágahavið” seems to be
in approximately the same location during
the present study compared to 1994-2004
(ICES, 2004).
At the coast of Norway there are sev-
eral local cod stocks, termed “Norwegian
coastal cod”, that are more reddish in ap-
pearance than north-east Arctic cod (Rollef-
sen, 1934; Jakobsen, 1987). Reddish col-
oured cod (“reyðfiskur” in Faroese) are
also common at the Faroes in shallow wa-
ters (< 100 m) near land. The material in
this study is not able to tell whether they
belong to local spawning stocks or spawn
together with other cod at “Norðhavið” or
“Vágahavið”. In the present study 43 of
them were tagged south of Mykines and
five recaptured, all near the tagging place.
Tagging experiments in December 2002
and November 2003 indicate that reddish
coloured cod have very limited migration
(unpubl.).
Migration pattern not
associated with spawning
The stationary habit of cod is in good
agreement with the earlier studies of cod
in Faroese waters (Strubberg, 1916; 1933)
and more recent experiments (Fjallstein
and Jákupsstovu, 1999). It is often ob-
served for juvenile cod in other areas, e.g.
on the Swedish west coast (Pihl and Ul-
mestrand, 1993), on the southern coast of
Norway (Danielssen and Gjøsæter, 1994),
and in western Norway fjord areas (Godø