262 THE LIVING ANIMALS OL 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 type 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 e.xposes 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 journeyings with careful attention to detail, much of which is 
now repudiated. Later theories hold that the shoals of herrings simply move, according to 
Photo by W, Saville-Kent^ T.Z.5.] YMilford^on^Sea. 
BARBELLED ARAPAIMA 
Kno^n also as the Daivson Ri'ver Salmon^ on account of the colour and fia'vour of its flesh 
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 any season of the year beyond reach of their drift-nets, which work at only 
moderate distances from the land, would be quite sufficient to convince 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, w^hen the identity and 
movements of these different “ races ” are more firmly 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 year 
indiscriminate!}', 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 
