OUB ECONOMIC SEA FISHES. 397 



they take to swarming in the inshore and estuaries — in this 

 respect the opposite of the ways of the Cod. 



With regard to the Clupekla (Herring family), Mcintosh and 

 Masterman say that : — " In the case of the four common Clupeoid 

 species — the Herring, Sprat, Pilchard, and Anchovy — the most 

 superficial examination of their eggs with the naked eye is 

 sufficient to distinguish them. The opacity and thick adhesive 

 membrane of the first, the translucence and delicate capsule of 

 the second, the clear peri-vitelline space and oil-globule of the 

 third, and the unique shape (ovoid) of the last are all characters 

 readily recognizable without the assistance of the lens." 



Size alone distinguishes the Gadoid eggs. The Herring's 

 egg belongs to the sunken type (demersal), a feature not shared 

 by its immediate family allies, nor of the Cod and flat-fish 

 families ; these groups embracing the chief economic British 

 fishes. It is this very exceptional circumstance, together with 

 the occasional eccentric periodic migratory habit of the fish itself, 

 that has compelled the Government repeatedly to recognize the 

 necessity for inquiry into the creature's ways, as a matter in- 

 volving the nation's fisheries' welfare. 



The fluctuations in the Herring fishery can scarcely yet be 

 satisfactorily accounted for, though the hue and cry against 

 trawling is met by the reply that the spawning areas, so far as is 

 known, are not those usually frequented by the trawlers. 



There is a slight excess of males among Herring. The female 

 carries from 20,000 to 50,000 ova. Spawning time varies round 

 the coast. Experiments instituted by Dr. Meyer, of Kiel, and 

 corroborated by other observers, prove that temperature of the 

 water materially influences the hatching process. Though seven 

 to ten days is the normal period, cold may vary this to forty days, 

 and pari passu the size of larvae. When first hatched the larva 

 is more advanced than in the Sprat, a buoyant egg-form. The 

 larval Herring has a biggish head, attenuated colourless body, 

 and the gut passes to proximal tail-end ; a broad fin-membrane 

 extends posteriorly from yolk-sac uniformly over back and belly. 

 In the early post-larval stages growth is lengthwise, thickening 

 of body not increasing in the same ratio. There is yet absence 

 of scales or silvery sheen. Later on, however, fins differentiate, 

 the anus acquires a more forward position, the body deepens, 



