HOËK— INTRODUCTORY _ VIII 



is found, it is represented by ver}' numerous individuals, but in the main, only at 

 a fixed season. The period of its occurrence lasts sometimes only a few weeks, 

 sometimes several months; apart from this period, the herring does not occur at 

 the usual places. In the different parts of the North Sea and Norwegian Sea the 

 herring swarms are found at very different seasons, and at certain places two 

 different races appear in the course of the year: one in spring and one in autumn 

 or winter. It is always definite races of herring which approach the coasts or 

 other fishing grounds, each race at its own definite season. 



Whilst the herring live pelagically, and the fishing thus takes place in the 

 open sea with drifting apparatus, the eggs are laid demersally on the bottom. 

 The spawning-grounds of the herring were discovered many years ago on the 

 German and Danish (Baltic) coasts, also at Scotland, some places on the English 

 as well as on the Dutch (Zuidersee) coasts. These have been studied in detail at 

 various places and described in various papers. The various herring-races spawn 

 at different periods of the year and under different physical conditions, which 

 are however definite and fixed for each race; it holds good in general, that the 

 herring spawning in spring come to the grounds lying near the coasts, where 

 the water is often brackish, whilst the herring spawning in summer and autumn 

 have their spawning places in deeper water and further from the coast, where the 

 salinity is higher. 

 The cod as a Ou thc otlicr haud, the cod, likewise the cod-group of fishes in general, is a 



migratory fish ^ottom-fisli which is taken , not with drift-nets, but with lines and trawls. Also, 

 it is only in part correct to say, that the cod is not caught on the same grounds 

 throughout the whole year. Whilst this holds good for the Norwegian fishing- 

 grounds, where the spawning cod ("Skrei") are taken in March and April especially, 

 and the feeding cod ("L,odde") in April and May, and likewise for the Icelandic 

 waters, where a true summer fishery for cod takes place, the case is different for the 

 cod on the Dogger Bank and so-called Fisher Banks, in so far that, it would be diffi- 

 cult to say, at what time the cod fishing (lines and trawl together) actually takes 

 place. Although the winter fishery of the cod in the North Sea, taken as a whole, 

 is more important than the summer fishery, (a 'difference, which occurs chiefly from 

 an examination of the coastal banks, as appears from Prof. Henking's analysis 

 of the hauls of Geestemünde steamers), yet in general, the cod is present in the 

 North Sea throughout the whole year in such large quantities, that it forms the 

 object of a definite fishery (the line fishery) in all months, as well as an important 

 part of the catches of the trawls. 



The presumption thus arises, that different races or forms are present here 

 also, and that, for example, the North Sea cod, which Prof. Heincke from his 

 investigations considers a stationary fish (i. e. localised), represents a different race 

 from that of the Norwegian cod of the lyofoten banks. It appears, however, as if 

 the cod races were not quite so sharply marked off from one another as those of 

 the herring; instead of having demersal eggs laid at fixed spawning grounds, like 

 the herring, the cod has so-called pelagic eggs, distributed far and wide; it is not 

 possible to divide the cod into spring and autumn spawners^, nor to distinguish 



I See, nevertheless, the note by Dr. Wemyss Fulton on the cod spawning in the North Sea in 

 autumn, in Public, de Circonstance Nr. 8—9, Copenhague. 1904. 



