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SHAD

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Originally appearing in Volume V24, Page 758 of the 1911 Encyclopedia Britannica.
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SHAD , the name given to certain migratory See also:

species of See also:herrings (Clupea), which are distinguished from the herrings proper by the See also:total See also:absence of See also:teeth in the jaws. Two species occur in See also:Europe, much resembling each other—one commonly called allis shad (Clupea alosa or Alosa vulgaris), and the other known as twaite shad(Clupea finta or Alosa finta). Both, like the See also:majority of herrings, are greenish on the back and silvery on the sides, but they are distinguished from the other See also:European species Clupea by the presence of a large blackish blotch behind the gill-opening, which is succeeded by a See also:series of several other similar spots along the See also:middle of the See also:side of the See also:body. So closely allied are these two fishes that their distinctness can be proved only by an examination of the gill-apparatus, the allis shad having from sixty to eighty very See also:fine and See also:long gill-rakers along the See also:concave edge of the first branchial See also:arch, whilst the twaite shad possesses from twenty-one to twenty-seven stout and stiff gill-rakers only. In their habits and See also:geographical See also:distribution also the two shads are similar. They inhabit the . coasts of temperate Europe, the twaite shad being more numerous in the Mediterranean. While they are in See also:salt See also:water they live singly or in very small companies, but during May (the twaite shad some See also:weeks later) they congregate, and in See also:great See also:numbers ascend large See also:rivers, such as the See also:Severn (and formerly the See also:Thames), the See also:Seine, the See also:Rhine, the See also:Nile, &c., in See also:order to See also:deposit their spawn. A few weeks after they drop down the See also:river, lean and exhausted, numbers floating dead on the See also:surface, so that only a small proportion seem to regain the See also:sea. At See also:Elbeuf on the Seine above See also:Rouen there was formerly a hatchery for the artificial See also:propagation of shad. The eggs are spawned in May and See also:June, and are similar in the two species; they are heavier than the fresh water in which they develop, but unlike the See also:herring's eggs they are not adhesive. They remain See also:free and See also:separate at the bottom of the river, carried down by the current or up by the See also:tide. In the See also:Elbe the twaite shad spawns below See also:Hamburg, the allis shad above See also:Dresden.

In See also:

November the See also:fry have reached 3 to 5 in. in length, but very few specimens in their second See also:year have been found in rivers. The majority seem to descend to the sea before their first See also:winter, to return when mature. On rivers in which these fishes make their periodical See also:appearance they have become the See also:object of a See also:regular See also:fishery. They are much esteemed on the middle Rhine, where they are generally known as " Maifisch." The allis shad is caught at a See also:size from 15 to 24 in., and is better flavoured than the twaite shad, which is generally smaller. Other, but closely allied species, occur on the See also:Atlantic coasts of See also:North See also:America, all surpassing the European species in importance as See also:food-fishes and economic value, viz., the See also:American shad (Clupea sapidissima), the gaspereau or See also:ale-wife (C. mattowocca or vernalis), and the See also:menhaden (C. menhaden).

End of Article: SHAD

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