208 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



results of the herring-fishery, the most remarkable one is this, that the 

 spring-herring fishery has not at all times commenced at the same 

 period of the year, but that at times it has had a tendency to extend 

 farther and farther into spring, which became particularly evident 

 toward the end of the so-called " herring-periods." The difference in 

 the time of the spring-herring's arrival on the coast may be a month 

 and a half from some time before New Year till some time in February. 

 From these experiences, Boeck could also in a certain manner predict 

 the decrease of the spring-herring fisheries which has taken place now. 

 This circumstance has so far been entirely unexplained ; if the herring 

 had its proper home in the deep sea-basins near the coast, what should 

 cause it to leave these later and later every year, or to come early after 

 the lapse of many years ? It could, on the other hand, easily be under- 

 stood that its arrival caused a shorter stay, and a disinclination to go 

 near the coast, so that the result of the fisheries would naturally be less. 



Sars supposes that on account of the varying strength and direction 

 of the currents in the open North Sea, which depend on the differences 

 of the weather, the distribution of small crustaceans in the sea will dif- 

 fer very much in the different years ; and, as the herring naturally stays 

 where it finds food, it will, when its migratory instinct awakens, be 

 nearer the coast, and consequently arrive sooner than in another where 

 it has been farther out and when its journey toward the coast required 

 longer time. As the movement toward the coast, in this case in a 

 southeasterly direction, will probably always occur about the same sea- 

 son of the year, (some time before the roe and milt, which likewise 

 develop at a certain season, are ready for spawning,) it follows of itself 

 that the spring-herring which comes in early is of a better quality, stays 

 longer near the coast, and will be able to go farther up the bays and 

 sounds ; in other words, that the fishery will yield a much better, richer, 

 and safer result than in the opposite case, when the herring only re- 

 mains for a season near the outermost coast, and is much thinner and 

 more exhausted, and when only occasionally a small school is chased 

 near the land by large fishes of prey. The herring-fishery may there- 

 fore yield a very different result, even if the same mass of herrings has 

 year after year been outside the coast and has produced the same quantity 

 of young ones. The final cause of the irregularity in the spring-herring 

 fisheries must therefore be sought in the changes of weather, cur- 

 rent, and temperature of the water in the outer sea, not so much during 

 the fishing-season as during the rest of the year, particularly during 

 the preceding autumn and summer. 



Whether there is in this respect a periodicity which corresponds with 

 that of the herring-fishery will be more satisfactorily explained by fu- 

 ture observations than by the study of the past. For the present, it 

 cannot be denied that such a thing is possible. " It is a fact that the 

 occurrence of small crustaceans during summer on the western coast 

 of Norway differs very much in the different years. Some years the 



