This supposed overfishing of the herring has resulted chiefly from our ignorance of the natural history of that fish—ignorance which has long prevailed, and which we are only now beginning to overcome. Indeed, much as the subject has been discussed during the last ten years, and great as the light is that has been thrown on the natural and economic history of our fish, considering the elemental difficulty which stands in the way of perfect observation, there are yet persons who insist upon believing all the old theories and romances pertaining to the lives of sea animals. We occasionally hear of the great sea-serpent; the impression of St. Peter’s thumb is still to be seen on the haddock; “Moby Dick,” a Tom Sayers among fighting whales, still ranges through the squid fields of the Pacific Ocean; and I know an old fisherman who once borrowed a comb from a polite mermaid! Not very long ago, for instance, the old theory of the migration of the herring to and from the Arctic Regions was gravely revived in an unexpected quarter, as if that romance of fish-life was still believed by modern naturalists to be the chief episode in the natural history of _Clupea harengus_; indeed in the present edition of the _Encyclopædia Britannica_ this migratory theory is still sustained (see article “Ichthyology”). The original migration story—which was invented by Pennant, or rather was constructed by him from the theories of fishermen—old as it is, is worthy of being briefly recapitulated, as affording a good point of view for a consideration of the natural and economic history of the herring as now ascertained: it was to the effect that in the inaccessible seas of the high northern latitudes herrings were found in overwhelming abundance, securing within the icy Arctic Circle a bounteous feeding-ground, and at the same time a quiet and safe retreat from their numerous enemies. At the proper season, inspired by some commanding impulse, vast bodies of this fish gathered themselves together into one great army, and in numbers far exceeding the power of imagination to picture departed for the waters of Europe and America. The particular division of this great _heer_, which was destined annually to repopulate the British seas, and afford a plenteous food-store for the people, was said to arrive at Iceland about March, and to be of such amazing extent as to occupy a surface more than equal to the dimensions of Great Britain and Ireland, but subdivided, by a happy instinct, into battalions five or six miles in length and three or four in breadth, each line or column being led, according to the ideas of fishermen, by herrings (probably the _Allis_ and _Twaite shad_) of more than ordinary size and sagacity. These heaven-directed strangers were next supposed to strike on the Shetland Islands, where they divided of themselves, as we are told; one division taking along the west side of Britain, whilst the other took the east