' ■} ^1 



D. Final Remarks. 



PEOPESSOB G. 0. Saks has, in my opinion, given the scientific 

 statement of the fundamental causes of tlie great Norwegian 

 fislieries. The biological investigations with which Mr. Sahs introduced 

 the practical scientific work, must be said to have given promises of 

 great results that were to come. It is, however, a matter-of-course 

 that a long series of special investigations still remain to be made. 

 It will have appeared from what has been previously said, that 

 both public authorities and private men liave had tlieir attention 

 drawn to the difficult problem of the causal relation between the 

 migrations of the fishes and the changing physical condition of the 

 sea. Especially a great number of temperature measurements have 

 been undertaken. The material of observations brought forward in 

 the course of the years is rather considerable. We can now have 

 a general idea of the distribution of temperature in normal years, 

 and the measurements have also given us some notions about the 

 swinging limits when the conditions take an unusual turn. 



Professor 0. Pettekson has drawn attention to certain aperi- 

 odical changes of temperature in the Gulf Stream, supposing these 

 to infiuence the regulation of the climate of Scandinavia*). In a 

 later work the same author has put the irregularities of Scandina- 

 vian winter fisheries in connection with the greater or smaller 

 volume of the Gulf Stream in winter. This is certainly a grand 

 idea, and if it should prove to be correct, it will at once also be | 

 made possible to form an approximate opinion of the predestination 

 of each year's fisheries, which would of course be of great economic 

 importance. 



It is Tinfoi'tunately true that we are at present rather far from 

 bein'"'' alile to "prophesy" the course of the Lofoten fisheries; for, 

 to my knowledge, there has not yet been proved any direct con- i 

 nection between the variations in the physical condition of the sea [ 

 find the fluctuations in the cod fisheries. The very circumstance I 

 that our herring fisheries show greater irregularities than the cod 

 fisheries, points at the cod being more capable than the herring 

 of withstanding negatively acting causes. It consequently becomes 

 more difficult to determine the result of the effects on the cod 

 fisheries than on the herring fisheries. 



*) "Om mOiligheteii af vaderleksforut^iiigelser for liingre tid". 



So much, however, seems to be certain, that the great conflux 

 of cod and herring to the coasts cannot be principally dependent 

 on hydrographic conditions, but on instincts in the animals them- 

 selves. The physical conditions consequently can only act in a 

 modifying way on the instinctive migrations. That however the 

 effects are strong enough to decide in many cases the fate of 

 the herring fisheries, has been proved by the excellent Swedish 

 investigators. 



On the other hand, the attempt to explain the irregularities 

 in the Lofoten fisheries by hydrographic causes has not succeeded. 

 It appears also that the migration of the cod to Lofoten occurs 

 one year after another under quite uniform conditions, because 

 temperature and saltness in the deeper layers undergo very small 

 changes indeed. It is true that it cannot be denied to be possible 

 that the migration up on the Lofoten banks themselves may be 

 delayed in such years when there is a comparatively sharp limit 

 between the water of 5 — 6 degrees and that of 3 degrees, and 

 that in consequence the catcfies in January and February will be 

 smaller than usually. But from what I have seen, I must conclude 

 that in the months of March and April the arrival of the cod and 

 the spawning will occur in spite of the lower degree of temperature, 

 and that a good fishing will then take place. In the month of 

 March they take in Lofoten 6U — 70 per cent of the total catch, 

 which no doubt depends on the circumstance that March is the 

 spawning month proper, when the migration in upon the banks 

 becomes general. 



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 in- 

 significant, we are obliged to look for another explanation of the 

 changes in the numbers of the immigration. I am apt to think 

 that much can be derived from changes in the number of 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 



