262 THE LIVING ANIMALS OF THE WORLD 



and very excellent fish they proved in camp. The TwaITE Shad is a somewhat smaller fish, 

 attaining to a maximum weight of perhaps a couple of pounds. It is not known to differ 

 materially in habits from the larger species. 



Reverting for a moment to the herring as a t}-pe of the family, a few words may be said 

 on some very interesting facts in connection with its life-history and commercial uses. In 

 the first place, the fact that the spawn sinks to the bottom is of more importance than 

 would at first sight appear, since it not only exposes this spawn to disturbance by the trawl, 

 but also subjects it to the voracity of cod, haddock, and other ground-feeding fishes. Some 

 little protection is afforded by a natural provision which enables the eggs to adhere to stones 

 and weeds, but this cannot in the long-run be of much service against prowling fishes. The 

 eggs of the shad, which likewise sink (in fresh-water), do not adhere in this way. 



The migrations of the herring, again, have furnished almost as much material for argument 

 to marine biologists as the migrations of birds in ornithological circles. Older naturalists 

 described marvellous Arctic journe)-ings with careful attention to detail, much of which is 

 now repudiated. Later theories hold that the shoals of herrings simph- move, according to 



fhM if IV. Say<lU-Ktnt, F.Z.S.] 



BARRELLED ARAPAIMA 



Krwzvn also ai the Daivion Rifer SahKon ^ on account of the colour and jia'vour of it> jiesh 



\,Mil/trJ-cn.Sta 



changes in the weather and temperature, backwards and forwards between the shore and the 

 deeper water outside; and so far as the fishermen are concerned, the mere fact of the fish 

 moving at anj- season of the )'ear be\'ond reach of their drift-nets, which work at only 

 moderate distances from the land, would be quite sufficient to con\ince them that the absent 

 fish had departed on world-wide travels. Much of the former acceptance of these extensive 

 migrations may have been due to confusion between the goings and comings of the different 

 races of herrings now recognised by biologists. It is also probable that, when the identity and 

 movements of these different "races" are more firmh- established, we shall be able to clear 

 up many of the difficulties at present surrounding the spawning-time of the herring, and to 

 show that it does not, as sometimes alleged, deposit its spawn at every season of the \'ear 

 indiscriminatel}', but that some herrings spawn at one season, some at another. Although 

 the herring is not, individually and by comparison with some other sea-fish, an enormously 

 fertile fish, its numbers must be fairly large, when we bear in mind that something like 

 50,000 crans a week are, in good seasons, packed in Shetland alone. Taking, as an average, 

 750 fish to the cran, this gives a weekly curing of not far short of 40,000,000 of herrings 

 in a single fishery. Owing indeed to the property, already noted, of adhering to stones 



