Finally, there is no evidence that herrings are to be met with in the extreme north of their range, at other times, or in greater abundance, than they are to be found elsewhere.
In the matter of its migration, as in other respects, the herring compares best with the salmon. The ordinary habitation of both fishes is no doubt the moderately deep portion of the sea. It is only as the breeding-time draws near that the herrings (not yet advanced beyond the matie state) gather together toward the surface and approach the land in great shoals for the purpose of spawning in relatively or absolutely shallow water. In the case of the herring of the Schlei we have almost the connecting link between the exclusively marine ordinary herring and the river-ascending salmon.
The records of the herring-fisheries are, for the most part, neither very ancient nor (with the exception of those of the Scotch Fishery Board) very accurately kept; and, from the nature of the case, they can only tell us whether the fish in any given year were readily taken or not, and that may have very little to do with the actual strength of the shoals.
However, there is historical evidence that, long before the time of Henry I, Yarmouth was frequented by herring-fishers. This means that, for eight centuries, herrings have been fished on the English coast, and I can not make out, taking one year with another, in recent times, that there has been any serious fluctuation in their numbers. The number captured must have enormously increased in the last two centuries, and yet there is no sign of diminution of the shoals.
1864 we had to listen to dolorous prophecies of the coming exhaustion of the Scotch herring-fisheries. The fact that the returns showed no falling off was ascribed to the improvement of the gear and methods of fishing, and to the much greater distances to which the fishermen extend their operations. Yet what has really happened? The returns of subsequent years prove, not only that the average cure of the decade 1869-'78 was considerably greater than that of the previous decade, but that the years 1874 and 1880 are absolutely without parallel in the annals of the Scotch herring-fishery, 1,000,000 barrels having been cured in the first of these years, and 1,500,000 in 1880. In the decade 1859-'68, the average was 670,000 barrels, and the highest 830,000.
In dealing with questions of biology, a priori reasoning is somewhat risky, and, if any one tells me "it stands to reason" that such and such things must happen, I generally find reason to doubt the safety of his standing.
It is said that "it stands to reason" that destruction on such a prodigious scale as that effected by herring-fishers must tell on the supply. But again let us look at the facts. It is said that 2,500,000,000, or thereabout, of herrings are every year taken out of the North Sea and the Atlantic. Suppose we assume the number to be 3,000,000,000, so