THE HERRING FAMILY 



167 



The transformation of the sprat larva into the perfect, fully- 

 developed sprat has not been carefully studied, but it is known 

 to resemble closely that of other fish of the herring family. But 

 concerning the growth and general history of the young we have 

 a considerable amount of evidence. The interesting observations 

 of Ewart and Matthews on Thames whitebait, already used in 

 connection with the herring, contain equally valuable information 

 concerning the young of the sprat. The condition and pro- 

 portional numbers of these are shown in the following table : — 



The number of small scaleless sprats gradually increased 

 during the last month, until 90 per cent, of the samples con- 

 sisted of these. This shows that the new brood of the year 

 began to appear in June, and increased to the end of August. 

 The transformation was completed when the fish were i| inch 

 long. We have no direct observations of the period of spawning 

 at the mouth of the Thames, but may infer that it extended from 

 March to June, the fish being first caught when about two months 

 old. We see therefore that the little sprats 2 to 3 inches long 

 taken at the beginning of the season in February, March, April, 

 and May, were just about a year old. 



The smallest ripe or nearly ripe sprats seen by Matthews in 

 the Firth of Forth were 4 to 4;^ inches long, and here again it is 

 probable that this length and the commencement of sexual 

 maturity is not reached before two }'ears of age. 



Young sprats fully developed, known locally as " britt," are 

 exceedingly abundant at Plymouth and other places on the south 

 coast of England, and are greedily devoured by mackerel, other 

 fishes, and sea-birds. They are commonly seen in summer time. 

 I have examined specimens in November 2*2 to 2"6 inches long. 

 In December I saw a large number killed in Millbay Docks by 



