11 



rather deep water. The reason is supposed to be that the fish 

 does not like to enter up into the colder water on the banks. 

 There may be something true in this, but it is also possible that 

 the stay of the fish on the edge for some time before spawning is 

 caused by the circumstance that most food is found there. It has 

 been supposed that the cod during the spawning time eats next to 

 nothing. It is certainly true that a great number of the stomachs 

 examined have been empty and contracted, but this may as 

 much be caused by want of food as by want of appetite. Several 

 circumstances, however, bear evidence that the cod eats even 

 close before spawning, and it is therefore likely that it stays 

 where most food animals are found, i. e. on the edge. When 

 the spawning time approaches, the fish goes up on tlie banks 

 to shed its roe and milt; it is then of course caught in more 

 shallow water. That temperature has any essential influence on 

 the migration from the edge to the spawning grounds, I do not 

 think can be maintained, after the observations hitherto made. 

 From the reports of the supervision cliiefs it is clear that in some 

 years large shoals of cod, already at the beginning of the fishing 

 season, migrate into fjords and bays, where the fishing then takes 

 place in comparatively shallow water. At the same time the exi- 

 stence is reported of some "aate", e. g. herrings or cuttlefish, and 

 it seems undoubtful that the disturbance in the normal migration 

 of the cod is caused by this "aate''. But this also proves that 

 food is of as much importance as temperature. Nor have we 

 hitherto any observations to support the idea that the presence of 

 "aate" in this case is owed to exceptional physical conditions of 

 the upper layers ; on the contrary the few temperature observations 

 we have from such years do not at any rate testify to anytliing 

 unusual. 



At the present standing of the investigations, the opinion seems 

 therefore most reasonable that the temperature of the water exer- 

 cises little influence on the fishing in Lofoten. The year 1892 for 

 instance gave a moderate produce, notwithstanding that the 5 

 degrees curve lay high up in the water. 



Dr. N. Knipowitsch*) has published a list of fishes existing 

 in the Murman Sea and the White Sea. According to this author 

 the cod is very general in the White Sea; ''Am haufigsten im 



") Annuaire du mus6e zoologique de I'academie imperiale des sciences de 

 St.-Petersbourg. 1897, no. 2, p. 144—1.58. 



Golfe von Kandalakscha, NW-Theil des Weissen Meeres." Great 

 quantities occur at the Murman coast, where it is the object of 

 large fisheries. The most easterly place on the said coast where 

 cod-fishing is carried on on a large scale is Wostotschnaja Liza 

 (Knipowitsch). Thus, generally speaking, it may be said that the 

 White Sea forms the limit of the extension of the cod to the East. 

 This is certainly not accidental. Mr. Knipowitsch (1. c, p. 155) 

 notes the Murman coast as belonging to the warm area. Tlie 

 bottom temperature is nearly without exception above 0" C. during 

 the warm season ; there is little formation of ice in winter, and no 

 drift ice. In the White Sea the summer temperatures in the upper 

 layers are rather high, but during the long winter large masses of 

 drift ice exist, and in the deeper layers the temperature in certain 

 places is all the year round below 0" C. To the east of the 

 White Sea the bottom temperature, even in the warmest months 

 of the year, is below 0° C, and during the greater part of the 

 year drift ice occurs in great masses. Temperature thus puts a 

 limit to the horizontal distribution of the cod ; it is exclusively 

 confined to the warm area; the 0-point is not exceeded. 



If this is applied directly on the conditions in Lofoten, it may 

 at once be noted that the temperature on the usual fishing banks 

 is never 0", but as a rule 2 — 5 degrees above zero. So far, the 

 temperature of the water should never be a hindrance to the fishing. 

 Such a conclusion, however, must be made with a great deal of 

 reserve. Allowing it to l3e it a fact that 0" C. is the lower limit 

 to the accomodating power of the species, we dare not directly 

 conclude that individuals usually living in water of 4° — 6° C. would 

 volunteer up into water the temperature of which greatly approaches 

 tlie boundary that puts a limit to the horizontal distribution of the 

 species. I do not think, however, that between the migrations of 

 the cod and the physical conditions of the water layers exists that 

 close connection that the investigations of recent years have ascer- 

 tained in the case of the herring. An abundant occurrence of food 

 animals certainly contributes far more to keeping the cod gathered 

 in one place than the circumstance that the water is 5" C. Nor 

 is it improbable that fluctuations in the fishing, partly at any rate, 

 may be ascribed to changes in the amount of lower animals gathered 

 on the banks. Bottom trawling in one and the same place, one 

 year after another, has produced facts indicating that the fauna in 

 some degree changes character. Our knowledge of these things,, 

 however, is very deficient. 



