Met UR 
5) 
THURSDAY, AUGUST 3, 1899. 
‘NORWEGIAN MARINE INVESTIGATIONS. 
\Bergens Museum. Report on Norwegian Marine In- 
vestigations, 1895-97. By Dr. Johan Hjort, O. 
Nordgaard and H. H. Gran. (Bergen: John Grieg, 
1899.) 
HIS Report contains two papers, the first, on the 
“Currents and Pelagic Life in the Northern 
Ocean,” by Drs. Hjort and Gran, and the second, ‘“‘A 
Contribution to the Study of Hydrography and Biology 
on the Coast of Norway,” by O. Nordgaard. 
In the first paper, the authors give the general results 
of their observations on the hydrography and pelagic 
life of the Northern Ocean obtained during recent years. 
More detailed results of their observations in Nor- 
wegian waters, with especial reference to the herring 
fishery, are reserved for future publication. 
It may at once be said that this work, though only an 
instalment, is a very important contribution to ocean- 
ographical knowledge, and well sustains the character of 
Scandinavian research. 
The first chapter deals with the hydrographical condi- 
tion of the Northern Ocean, and the second chapter con- 
tains plankton studies in the same region. Then follow 
voluminous and detailed tables of the actual observations, 
These tables are illustrated by a series of seven plates, 
which show easily and very clearly the peculiarities of 
the region under description. 
The Northern Ocean, as a deep-water basin, lies on 
the polar side of a curved line passing through Iceland, 
the Far6 Islands, and reaching the Norwegian coast at 
the point where its trend changes from north to north- 
east. The shallow water portion includes all the Nor- 
wegian littoral waters and the portion of the North 
Sea between Norway and Scotland lying north of lati- 
tude 57° or 58° N. The Wyville Thomson ridge connect- 
ing Iceland with the Farés and the Orkney Islands is 
debatable ground separating the Atlantic from the Arctic 
areas. The position and the bathymetric characteristics 
of the different regions are very well shown in Plate L., 
taken from Mohn’s “ Northern Ocean.” 
Along the entire Norwegian seaboard there are three 
deep regions of well-marked hydrographic characters : 
_ (1) The region of periodical changes to a depth of 200 or 
250 metres ; (2) the Atlantic region to a depth of 500 
metres ; and (3) the Arctic region. Referring to this 
classification, the authors say : 
“ Of these regions it is chiefly the uppermost that is of 
interest to us, as it is our main purpose to unravel all the 
conditions which may influence the migration of fishes ; 
and it may well be presumed that the great changes pro- 
duced by currents, by summer warmth and winter cold, 
and the variations from year to year of the different 
factors, may be of the greatest importance to the 
periodical fisheries.” 
In pursuing the investigations of these conditions, five 
sections of the sea off the coast between Stavanger and 
Lofoten were made in 1895 by Hjort, and the same ground 
was gone over by Nordgaard in the winter of 1896. The 
NO. 1553, VOL. 60] 
results of these investigations are shown graphically in 
Plates VI. and VII. ‘The figures in these plates take the 
form of sections running out from the Norwegian coast 
toa depth not exceeding 4oo metres, and showing the 
distribution of depth, temperature and salinity. Of these, 
the most interesting are those made in the same locality 
in summer and in winter. The difference of season 
affects principally the water at and near the surface, and 
is dependent on the rainfall in Norway. If the west 
coast of Norway were a perpendicular cliff, and the whole 
of the rain which falls on it ran eastwards, the fluc- 
tuation of conditions with which this paper deals would 
be either non-existent or insignificant. The physical 
observations of the papers are mainly directed to chron- 
icling the variations in the salinity of the coast waters, 
and especially in the quantity of water of low salinity, 
which has a tendency to cover the surface and monopolise 
the summer heat received from the sun, of which it con- 
tributes next to none to the layers immediately below it. 
This view, that the freshening of the coastal waters, with 
all its consequences, is due to the mixture of Atlantic 
water with fresh water from the continent, and not to 
the addition of water from the Arctic ocean, is developed 
in considerable detail in the paper. In so far the paper 
is of a polemical and, indeed, of a more or less national 
character, because the opposing view is_ especially 
identified with Sweden, and the one supported by the 
authors with Norway. It is, however, a ferm of polemic 
from which nothing but profit is likely to result to 
science. With regard to the evidence afforded by 
plankton studies, which have been held to favour the 
Arctic theory, the authors say in their 7észmeé :-— 
“As all inflowing bodies of oceanic water are of an 
Atlantic kind, the Arctic organisms, which may be met 
with at certain times, must in any case pass through 
Atlantic water if they really are derived from the Arctic 
currents, but their subsequent appearance in the colder 
and fresher waters on the coast is no proof of the 
coastal water’s Arctic origin.” 
The concluding paper by Nordgaard, dealing mainly 
with the food of the cod, is very interesting, but not of a 
kind to be easily abstracted. In presenting the results 
of his investigations, he makes some important remarks. 
He admits that the fluctuations of the herring fishery are 
largely, though not exclusively, due to changes in the 
physical conditions of the sea in the spawning regions. 
Referring to the cod, he says :— 
“We are thus led to the conclusion that a principal 
factor in the produce of the Lofoten fisheries is the number 
of the fish that migrate inwards, and as the migration 
from the ocean, according to the observations hitherto 
made goes on in such a great depth that the annual 
variations in the physical conditions are very insignificant, 
we are obliged to look for another explanation of the 
change, in the numbers of the immigrations. I am apt 
to think that much can be derived from changes in the 
numbers of the fish staying on the outer banks. In the 
same way in which we speak, for instance, of a bad 
grouse season, by which we mean that the number of 
grouse is small, we may certainly also speak of a bad 
cod season.” 
It will be seen that this, as well as the preceding 
papers, are of a very detailed character, and they well 
repay careful study. Worn. 13% 
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