SPAWNIITG OF THE HERRING. 559 



earlier, so that finally the fisheries (jommenced before New Years; and that this change was followed 

 by another, the Herrings coming later and later, till the fisheries did not commence before Feb- 

 ruary. This peculiarity, however, was thought to be a consequence of the irregularity with vvhich 

 the Herrings visited the same places on the coast. It was not till Axel Boeck began to investigate 

 the matter that this whole question was treated from a more scientific standpoint. He showed 

 that the coming of the herrings to the coast at different times during the period was subject to 

 certain rules, and that this regularity in the movements of the Herrings was observed not only 

 during the Norwegian spring herring fisheries of the seventeenth aud eighteenth centuries, but 

 also during those herring fisheries which were going on on the coast of Bohuslan during the 

 second half of the fifteenth and seventeenth centuries. This peculiar phenomenon has therefore 

 become far more important than it was thought to be in former times ; and it may well be said to 

 contain the key to the question of the periodicity of the great Scandinavian herring fisheries. 

 Boeck was not able to assign any cause for these entirely regular changes in the time of the 

 Herrings' visits to the coast. This has been attempted, however, by G. O. Sars and myself, and 

 an account of these attempts will be given below. 



In a paper entitled "The Great Bohuslan Herring Fishery,"^ A. N. Ljungman gives a very 

 interesting account of the periods of abundance of Herring in Sweden and of the herring fisheries 

 of that region from 1000 A. D. to the present date. 



Eepeodtjction. — There are several interesting series of observations upon the spawning 

 habits of the Herring, the hatching of the egg, and the development of the young ; all of which 

 may be found in the later volumes of the Report of the United States Commissioner of Fisheries. 



In his lecture on the Herring, Professor Huxley describes in a very concise and lucid way 

 their spawning habits. He remarks: "We have hitherto met with no case of full or spawning 

 Herrings being fonnd, in any locality, during what may be termed the solstitial months, namely, 

 June and December^ and it would appear that such Herrings are never (or very rarely) taken in 

 May, or the early part of July, in the latter part of November, or the early part of January. But 

 a spring spawning certainly occurs in the latter part of January, in February, in March, and in 

 April; and an autumn spawning in the latter part of July, in August, September, October, and 

 even as late as November. Taking all parts of the British coast together, February aud March 

 are the great months for the spring spawning, and August and September for the autumn 

 spawning. It is not at all likely that the same fish spawn twice in the year; on the contrary, the 

 spring and the autumn shoals are probably perfectlj^ distinct; and if the Herring, according to 

 the hypothesis advanced above, come to maturity in a year, the shoals of each spawning season 

 would be the fry of the twelvemonth before. However, no direct evidence can be adduced in 

 favor of this supposition, and it would be extremely difficult to obtain such evidence. 



"I believe that these conclusions, confirmatory of those of previous careful observers, are fully 

 supported by all the evidence which has been collected; and the fact that this species of fish has 

 two spawning seasons, one in the hottest and one in the coldest month of the year, is verj' curious. 



"Another singular circumstance with the spawning of the Herring is the great variety of the 

 conditions, apart from temperature, to which the fish adapts itself in performing this function. On 

 our own coast, Herrings spawn in water of from ten to twenty fathoms, aud even at greater depths, 

 and in a sea of full oceanic saltness. Nevertheless, Herrings spawn just as freely not only in the 

 narrows of the Baltic, such as the Great Belt, in which the water is not half as salt as it is in the 

 North Sea and in the Atlantic, but even in such long inlets as the Schlei in Schleswig, the water 



' A translation of which is published in United States Fish Commission Keport, part vi ; pp. 221-239. 



