Náttúrufræðingurinn - 1951, Qupperneq 34

nAttúrufræðingurinn
80
the Kögur section was calculated. The movement of the Irminger Current is found to
be strongest at the slope whereas the movement of the polar water increases in velocity
as the continental shelf of Greenland is approached. The values obtained agree fairly
well with those previously reported by Helland-Hansen and Nansen.
The influx of Atlantic water off the north coast of Iceland in different years is
discussed. The distribution of this water in three periods during the summer of 1948
is shown. The diagrams showing the variations in temperature and salinity during July
in different years at a position 12—13 nautical miles off Siglufjörður demonstrate the
abnormally weak influx of Atlantic water during the sttmmer of 1949.
A section extending from Langanes to Jan Mayen operated twice during the summer
months of 1949 confirms the opinion expressed by Helland-Hansen and Nansen that
the movement of the East-Icelandic Current is chiefly limited to the slope on the right
side of the current. Near the Jan Mayen bank a westward movement is indicated.
Compared to earlier years there appears to have been unusually large masses of cold
arctic water in the area between Langanes and Jan Mayen during the summer of 1949.
In 1948, however, the extension of the East Icelandic Current was much less than some
previous years as indicated by Danish and Norwegian investigations.
The author discusses the hypothesis recently formulated by Devold tliat the failure
of the herring fishery on the North Icelandic grounds during recent years is due to
unusual strength of the East-Icelandic Current. The author points out tliat the hydro-
graphic material from the summer of 1948 which was one of the poorest herring
seasons seems to contradict Devold’s hypothesis..