Herring (Clupea harengus, Häring in German, le hareng in French, sill in Swedish), a fish belonging to the genus Clupea, of which more than sixty different species are known in various parts of the globe. The sprat, pilchard or sardine and shad are species of the same genus. Of all sea-fishes Clupeae are the most abundant; for although other genera may comprise a greater variety of species, they are far surpassed by Clupea with regard to the number of individuals. The majority of the species of Clupea are of greater or less utility to man; it is only a few tropical species that acquire, probably from their food, highly poisonous properties, so as to be dangerous to persons eating them. But no other species equals the common herring in importance as an article of food or commerce. It inhabits in incredible numbers the North Sea, the northern parts of the Atlantic and the seas north of Asia. The herring inhabiting the corresponding latitudes of the North Pacific is another species, but most closely allied to that of the eastern hemisphere. Formerly it was the general belief that the herring inhabits the open ocean close to the Arctic Circle, and that it migrates at certain seasons towards the northern coasts of Europe and America. This view has been proved to be erroneous, and we know now that this fish lives throughout the year in the vicinity of our shores, but at a greater depth, and at a greater distance from the coast, than at the time when it approaches land for the purpose of spawning.
Herrings are readily recognized and distinguished from the other species of Clupea by having an ovate patch of very small teeth on the vomer (that is, the centre of the palate). In the dorsal fin they have from 17 to 20 rays, and in the anal fin from 16 to 18; there are from 53 to 59 scales in the lateral line and 54 to 56 vertebrae in the vertebral column. They have a smooth gill-cover, without those radiating ridges of bone which are so conspicuous in the pilchard and other Clupeae. The sprat cannot be confounded with the herring, as it has no teeth on the vomer and only 47 or 48 scales in the lateral line.
The spawn of the herring is adhesive, and is deposited on rough gravelly ground at varying distances from the coast and always in comparatively shallow water. The season of spawning is different in different places, and even in the same district, e.g. the east coast of Scotland, there are herrings spawning in spring and others in autumn. These are not the same fish but different races. Those which breed in winter or spring deposit their spawn near the coast at the mouths of estuaries, and ascend the estuaries to a considerable distance at certain times, as in the Firths of Forth and Clyde, while those which spawn in summer or autumn belong more to the open sea, e.g. the great shoals that visit the North Sea annually.
Herrings grow very rapidly; according to H. A. Meyer’s observations, they attain a length of from 17 to 18 mm. during the first month after hatching, 34 to 36 mm. during the second, 45 to 50 mm. during the third, 55 to 61 mm. during the fourth, and 65 to 72 mm. during the fifth. The size which they finally attain and their general condition depend chiefly on the abundance of food (which consists of crustaceans and other small marine animals), on the temperature of the water, on the season at which they have been hatched, &c. Their usual size is about 12 in., but in some particularly suitable localities they grow to a length of 15 in., and instances of specimens measuring 17 in. are on record. In the Baltic, where the water is gradually losing its saline constituents, thus becoming less adapted for the development of marine species, the herring continues to exist in large numbers, but as a dwarfed form, not growing either to the size or to the condition of the North-Sea herring. The herring of the American side of the Atlantic is specifically identical with that of Europe. A second species (Clupea leachii) has been supposed to exist on the British coast; but it comprises only individuals of a smaller size, the produce of an early or late spawn. Also the so-called “white-bait” is not a distinct species, but consists chiefly of the fry or the young of herrings and sprats, and is obtained “in perfection” at localities where these small fishes find an abundance of food, as in the estuary of the Thames.
Several excellent accounts of the herring have been published, as by Valenciennes in the 20th vol. of the Histoire naturelle des poissons, and more especially by Mr J. M. Mitchell, The Herring, its Natural History and National Importance (Edinburgh, 1864). Recent investigations are described in the Reports of the Fishery Board for Scotland, and in the reports of the German Kommission zur Untersuchung der Deutschen Meere (published at Kiel).
