200 SALT-WATER FISHES 



The spawning of the sprat has been observed in the Firth 

 of Forth, and generally takes place nearer the land than that 

 of other marine Clupeida;. The spawning of anchovies has 

 been observed in the Zuyder Zee in summer time, and its 

 floating eggs were taken in the tow-net off Lytham (1896) 

 by Mr. Ascroft, who hatched out the larva;. 



The spawning of shad is sufficiently familiar in many of 

 our rivers, and is, moreover, easily studied in private hatcheries 

 both on the Continent and in America. In the latter country 

 the eggs are artificially hatched on an immense scale, and it 

 has been found that the action of direct sunlight accelerates 

 the hatching by at least twelve hours, and without apparently 

 weakening the larvte. 



The herring, sprat, pilchard, and anchovy may be dis- 

 tinguished at almost any stage of their growth without much 

 difficulty. In the adult fish, which chiefly concerns us here, 

 the herring has the commencement of its back fin just 

 half way between the tip of the nose and the start of the 

 tail fin ; in the sprat the dorsal fin starts a little nearer 

 the tail ; in the pilchard a little nearer the nose. Given the 

 aid of a yard measure, it would be difficult to indicate a 

 simpler means of recognition in comparing three individuals. 

 Other differences are found in the larger scales of the pilchard, 

 and more serrated belly edge of the sprat. The pilchard 

 and shads also have radiating lines on the gill-covers, 

 which are not found in any of the rest. The backbone 

 furnishes an excellent distinction between the sprat and herring, 

 for the former has never more than forty-eight vertebrae, 

 and the herring has never less than fifty-six. Shads are 

 rather like pilchards in their greenish colour, but they have 

 smaller scales, and their lower edge is also rougher. They 

 resemble each other somewhat closely, but the twaite shad 

 has a line of dark spots nearly half way along the sides, and 

 its gill-rakers are fewer, longer, and thicker than those of 

 the allis. 



