Fróðskaparrit - 01.01.2005, Síða 105

MERKINGARROYNDIR VIÐ FØROYSKUM TOSKI 1952-1965
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to deeper waters (50-100m) close to the
islands (Fjallstein and Jákupsstovu, 1999).
When they reached commercial size (>
50 cm), they were recaptured on tradition-
al cod fishing grounds at depths between
50-150 m (unpubl.).
From 1997 to present, extensive tagging
experiments have been performed with
cod (Steingrund, 1999; unpubl.). In these
experiments, cod were larger (50-70 cm)
and usually tagged in deeper waters (90-
400 m) than in the 1952-65 material. The
results from these experiments are only
dealt with if they have direct relevance to
the 1952-65 material.
Materials and methods
Tags
Cod during many of the experiments (see
Appendix 1) were tagged with ebonite
discs as described in Strubberg (1933).
Lea’s hydrostatic tag was otherwise used
(Anon., 1953; Jónsson, 1996). The ebon-
ite discs were attached to the operculum
and the Lea tags in front of the first dorsal
fin.
Tagging procedure
The tagging experiments were normally
perfbrmed twice a year, during spring
and autumn. In the period 1952-64, small
open boats or cutters were hired, whereas
the research vessel “Svabo” was used dur-
ing 1964-65.
The fish were mainly caught by hand-
line, using natural bait, and sometimes by
hand-jigging, using artificial bait. Lon-
gline or trawl was used in a few cases.
Only fish in excellent condition were
tagged. The length was recorded (usually
rounded down to whole centimeters) and
the fish released.
When catch rates became too low in a
particular place, the boat moved to another
place. Weather conditions sometimes de-
termined which places were selected for
tagging experiments.
Publicity and rewards
There was a regular communication with
fishermen both by articles in local news-
papers and personal communication. The
reward was usually 5 DKK per tag, corre-
sponding to about 100 DKK today (about
$17). We assume that the reward, person-
al contact and communication to Faroese
fishermen has been sufficient in order to
keep the interest in the project on a high
level. It is possible, however, that foreign
fishermen (from England and Scotland)
may not have had the same interest.
Recaptured fish
We tried to collect as much information
about recaptured fish as possible, i.e. date,
position, fish length, weight, sex, maturity
and age (from otoliths).
The position of recapture was often
reported as a distance from one or two
landmarks, or as a name of a fishing site,
and coordinates (latitude and longitude)
were set later by the first or fourth author.
No coordinates were set if the description
was too imprecise, e.g. when two far-away
locations were equally likely. The posi-
tions near land reported mainly by Faroese
fishermen were normally considered to be
accurate. This was not always the case for