160 FIRST LW8S0NS IN ZOOLOGY. 



wife ; and the menhaden or pogy (Brcvooriia tyrannun), 

 which extends from the coast of Maine to Cape Hatteras. 

 These, with the cod, hake, haddock, salmon, and a few 

 other species, comprise our most yaluable marine food- 

 fishes. The fisheries of the United States yield about 

 $43,000,000 annually, whilst those of Great Britain amount 

 in value to about 18,000,000, and those of Norway to about 

 114,000,000. 



The herring (Pig. 164) is a deep-water fish which visits 

 the coast in spring in immense schools, in which the females 

 are three times as numerous as the males, to spawn, select- 

 ing shoal water from three to four fathoms deep in bays. 



Fia 164.— The Herrii^, Clwpea harengus. (One third natural size.) 



where the eggs hatch. At this season, and early in the 

 summer, hundreds of millions are caught, especially on the 

 Canadian, Newfoundland, and Labrador coasts. The Eng- 

 lish whitebait is the young of the herring. The herring is 

 caught in deep nets with meshes large enough to capture 

 individuals of ordinary size, the nets having a finer mesh 

 than those used for the mackerel-fishery. 



The alewife and shad are said to be anadromons, from 

 their habit early in spring of visiting the coast and ascend- 

 ing rivers in vast numbers to spawn. The eggs are of 

 moderate size ; the ovaries are said to contain about 35,000, 

 and at times as many as 100,000 or 150,000, eggs. They 

 are discharged near the surface, sinking slowly to the bot- 

 tom. The shad eats little or nothing in fresh water, being 



