i "ini ination. 



249 



comparison be made with statistics for 1859—85, it will be seen 

 that the years 1886 — 95 were particularly favourable ones, while 

 from 1896 up to the present time, there have been unusually bad 

 seasons. In this clearly defined state of things, there lies an in- 

 creased possibility of getting at the causes thereof, and I have tried, 

 in various ways, to connect facts, but it was a long time before I 

 succeeded in finding anything which seemed to point to a law. 

 During my work, however, the opinion has gained upon me 

 that the movements in the sea itself have a great effect upon 

 the direction taken by the fish. A. Boeck, to whom much is due 

 for his study of the spring-herring fishery, was of the opinion 

 that the herrings went against the stream, but later observers 

 do not agree with him in this matter, and I believe that both 

 herrings and cod most probably, as a general rule, move with 

 the stream. So that a very careful study of the currents in the 

 sea is of great practical import. In recent years, V. Bjerknes, 

 Sanhstkom and Hellaxd-Haxsex have developed the analytic 

 apparatus to be used in calculating the movements of the sea, but 

 it would seem that these scientists have taken no account of the 

 wind. In his well known work on the Norwegian Sea, Mohn, has, 

 on the contrary, very strongly emphasized the importance of the 

 wind as a cause of currents, and this opinion is shared by many 

 foreign hydrographers. With regard to the mutual dependence of 

 winds and currents upon each other, it may, generally speaking, 

 be said that a constant off-land wind causes a corresponding current 

 from land, while during a constant sea-wind, the water is forced 

 in towards the coasts. In the spring (March and April) the water 

 on the west coast of Norway is particularly low, the supply of 

 fresh water being slight, but more especially does the continual 

 land-wind blow a quantity of water away from the coasts. At the 

 end of March this year (1904), there was in Bergen continually 

 easterly winds, which were so strong that they kept the tide waves 

 so much at bay as to make the difference between ebb and flow 

 very slight indeed. Similarly, a strong sea-wind in the late autumn 

 is able to keep the water for days at an unusually high level. It 

 is, however, clear, that, during the movements to or from the coast 

 of the surface water, a compensating current must be set in motion 

 in the deep water; it has long been a recognized phenomenon in 

 the fiords, that the surface and under-currents go in contrary 

 directions. If we now take it for granted that both herrings and 

 cod are to a certain extent drawn along by the currents, it natur- 

 ally follows that one must try to find out whether it be the motions 

 in the surface-layers or the deeper situated compensation-currents 

 which exert a special influence on the direction taken by the fish. 

 Keeping this question to the fore, I have gone through a large 

 number of fishery reports, and it seems from these to be fairly cer- 

 tain that the herrings move coastwards especially in the surface 

 layers, while the „skrei" travels along in the deeper layers. This 

 would imply that herrings are most influenced by the surface-cur- 

 rents, cod by the compensation-currents. In reports on spring- 

 herring fishery, it is, for instance, mentioned that small lots of 

 herring (the so-called „Aater") are ofteii seen drifting along with 

 the stream, and there are many remarks made by skippers about 

 the sea being of a peculiar colour just beyond the spring fishery 

 district, and that this is caused by the large number of herrings 

 which are there present, and this fact denotes that the fish cannot 

 be at any great depth. There is, however, no reason why the 

 herrings should not lower themselves deeper in the water, but as 

 a general rule, I think one may conclude that they move principally 



in the upper layers. On the other hand, no one has observed 

 shoals of ..skrei" oft" the coast, and the first ..skrei" of the year 

 is, in fact, usually taken from a depth of 100 — 150 meters. It 

 must, therefore, be supposed that as cod and herrings, to a certain 

 extent, depend upon contrary current phases, a particularly good 

 spring-herring fishery would prevent a correspondingly good cod 

 fishery in the same district : for a strong tendency of the upper 

 layers towards the coast certainly takes herrings along in the cur- 

 rent, but this at the same time causes a compensation current in 

 the deep water, ami this current hinders the cod in its passage to 

 the spawning places. It is indeed specially mentioned in reports 

 on spring-herring fishery, that, in really good herring years, cod 

 does not, as a rule, occur in any quantity. 



The „skrei" fishery takes place in Lofoten in the months 

 January— April. 



Let us have a look at Mohn's Climate tables (Vol. IV), so as 

 to get an idea of the winds prevalent at this time of year. We 

 find that at Skomvaer, from October— April, the prevailing wind is 

 from S. At Andenes station, there is prevalent southerly wind 

 from September— April, and at Fruholmen station from SE in the 

 months of October— March. From this, it would follow that, as a 

 rule, the wind and the surface current go in a contrary direction 

 to that taken by the cod from the northern banks, while the under- 

 currents probably go in the same course as that which the cod 

 has to follow. On looking through the remarks on the weather 

 which are found in the annual reports of the Lofot fishery, I have 

 got the impression that the cold-bringing easterly winds by no 

 means retard the fishing, as has been stated, but that they, on the 

 contrary, assist it. For instance, the following paragraph is found 

 in the chief controller's report on the excellent season 1895: — 



„Easterly and north-easterly winds were prevalent, with clear 

 skies and frost, north-westerly and westerly winds and snow were 

 not unusual either, but southerly winds and rain were rare." When 

 easterly winds prevail, it is found that the surface temperature on 

 the Lofoten banks falls considerably, and the principal reason for 

 this fact is that the wind sweeps along the cold surface water 

 from the fiords, while the under-currents undoubtedly go in a con- 

 trary direction and carry along the cod. 



As a result of the foregoing, it is quite natural to conclude 

 that the fluctuations in the Lofot fishery really are due to the 

 distribution of atmospheric pressure, or, in other words, the direction 

 and strength of the winds. As, however, there are many difficulties 

 to be surmounted in studying the changes in the influence of winds, 

 I have chosen another thing, which is greatly affected by them, 

 namely downpour. I take it for granted that the annual downpour 

 must, taken generally, give a measure of the influence of the winds. 

 By noting the changes in downpour from year to year, one must 

 be able to form an opinion of the relation of the sea and land 

 winds to each other; for upon this, according to the theory stated 

 above, depends the success of the fisheries. In the „ Observations 

 of the Downpour in Norway" published by the Norwegian meteoro- 

 logical institute, we have an excellent aid in studying the fluctu- 

 ations in downpour. From this work, I have taken the necessary 

 data to enable me to give the following table, which shows the 

 annual average height of downpour in millimeters, at a series of 

 coast stations, during the years 1886 — 95 and 1896 — 1902, as well 

 as the calculated normal height. 



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