I 62 



MARKETABLE BRITISH MARINE FISHES 



It is evident from this that larval herring not yet transformed 

 to the fully developed condition began to appear in April, were 

 most numerous in May, and were still a large proportion of 

 the whole in June, while the older scaled forms became 

 more numerous in June and July, and in August no larval 

 forms remained, all the young herrings being over 2 inches in 

 length. All this points strongly to the occurrence of a spring 

 spawning at the mouth of the Thames in March and April, but 

 unfortunately such spawning has not been sufficiently investi- 

 gated. But in Yarrell's BritisJi Fishes, first edition, vol. ii., p. 117, 

 there is an account of certain herring which that author found in 

 the Thames. They were captured by the sprat fishermen, and 

 were heavy with roe at the end of January, spawning in February. 

 They were small, only yh inches long, and Yarrell considered 

 them to be a distinct species. The fishermen of Leigh, on the 

 north shore of the Thames estuary, maintain that the herrings 

 they catch in winter, which they call " yorlings," a corruption 

 apparently of yearlings, are not the same as sea herrings, but a 

 different variety. These are apparently the same which Yarrell 

 described, and probably are a race of spring, brackish-water 

 herrings belonging to the mouth of the Thames. It is probably 

 from these herrings, whose spawning may continue in March and 

 April, that the young which form so large a proportion of Thames 

 whitebait are derived. The actual place, however, where the 

 spawn is deposited has not been ascertained. 



The history of the larvse hatched on the spawning beds of 

 the Isle of May in the Firth of Forth, has not been completely 



