Íslenskar landbúnaðarrannsóknir - 01.09.1978, Side 110

108 ÍSLENZKAR LANDBÚNAÐARRANNSÓKNIR
onc.e. Each lot contained about 1.000 fish
each, for a total number of 8.000 fish tag-
ged. One group consisted of wild smolts
captured on their downstream migration;
a second group consisted of hatchery fish
held and tagged at the Ellidaár; a third
group consisted of hatchery fish tagged at
Kollafjördur Fish Farm and released di-
rectly into the Ellidaár; and a final group
was a control group for the direct release
tagged at Kollafjördur and held at Ell-
idaár prior to release. For convenience,
these groups will be referred to as wild
fish, handled hatchery fish, direct Ellidaár
release, and control hatchery fish.
Control group and direct release.
Both the direct Ellidaár release and the
control hatchery fish were microtagged at
Kollaíjördur during the first days of May.
On May 5, the control group was hauled
to the Ellidaár and placed in a concrete
raceway-type pond a few meters from the
river’s edge (Fig. 3-bottom). This group
was held for a month and fed to satiation
two or three times daily with Swedish
Ewos dry feed. The fish were liberated
from May 28 tojune 10. Thedirect release
fish were kept at the hatchery for the
month following tagging and were fed in
the same way as the control fish. On June
4 they were hauled directly from the
hatchery and liberated into the river.
Wild fish.
A fyke net with extended wings was used
to fish the entire main branch of the Ell-
idaár between May 23 and June 8 (Poe
1975). All smolts were funneled into a live
box from which the fish were removed
hourly. The captured fish were placed in a
bucket and quikly taken to and placed in a
compartment of a holding pond. The
minor branch of the Ellidaár was fished
with an eel trap; some smolts were also
taken from it.
After capture, the wild fish were held for
1-5 days and then tagged. Following
tagging they were held one additional day
and then liberated. During the period of
captivity, they were offered food but rarely
ate. -
Handled hatchery fish.
The handled hatchery fish were hauled to
the holding ponds on May 5 without being
tagged. They were then treated as closely
as possible like the wild fish. Specifically,
they were tagged, a few hundred fish at a
time, over the period of May 23—June 8.
The day prior to tagging, they were dip-
netted out ofone compartment and placed
into an adjacent compartment of the
raceway. The day following tagging, they
were liberated.
Method of recovery
The recovery of microtagged fish at Ell-
idaárin 1976 and 1977 was primarily from
the sports fishery, although considerable
numbers of tags were obtained from the
trap closures which took place in August
1976. According to regulation of the
Reykjavík Sports Club, which leases the
river, each salmon must be brought to the
fishing hut at the end of the fishing period
to be weighed and recorded by the fishing
inspectors. The fishing time at Ellidaár is
divided into V2 days and the salmon are
brought to the fishing hut at 1:00 P.M.
and 9:00 P.M.
A representative from the Institute of
Freshwater Fisheries was always present
at that time to examine the fish and to