Íslenskar landbúnaðarrannsóknir - 01.09.1978, Side 131

GROWTH RATES OF TROUT AND CHAR 129
Fig. 2. Brown trout from Laxá in Northeast Iceland. Photo Rafn Hafnfjörd.
The stomach content was analyzed by
combining the stomach content from all
fish samples taken in the lake, Table 4.
Chironomids are a dominant food item
together with the snail, Lymnea peregra. No
attempt was made to examine the food
web througout the season, but it is known
that bottom crustaceans, especially
Lepidururs arcticus and perhaps Eurycercus
lamellatus, play an important role in late
summer and fall.
Substantial catches were made only in
Fossvatn. A maximum of 11,800 fish is
recorded for 1975 in the catch statistics of
the Fisheries Association. The fish weigh
150-250 g and the yield is about 20-30
kg/ha/yr. This is very high compared with
the yield of 5—7 kg/ha/yr of brown trout for
Norwegian lakes.
ARCTIC CHAR IN EAST FRID-
MUNDARVATN
East Fridmundarvatn is located 435 m
above sea level with a surface area of 2.36
km2. It is a shallow lake with a maximum
depth of 1.15 m and an average depth of
0.8 m. Two small springs empty into the
southern end and a small brook drains
from the northern end to lake Gilsvatn.
The bottom of the lake is soft mud, mostly
covered with Myriophyllum sp. and the
bluegreen algae Nostoc sp. The annual
primary production has been estimated to
be in the range of 200-400 g C/m2/yr
(Aðalsteinsson, personal communica-
tion).
The fish populations consist predomin-
antly of Arctic char, (Fig. 3), a few brown
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