Sprats Inferences Drawn ; Spawning Grounds. 85 



fish first become mature; (c) that breeding condition is not 

 attained until they are well nigh four inches in extreme length ; 

 (d) that a large proportion of the younger fish are temporarily 

 resident, and distributed hither and thither in the estuary and 

 creeks from autumn till spring, the majority of yearlings then 

 join and migrate with the adult shoals ; (e) that while no racial 

 distinction exists, yet practically the fishermen's notion of sea 

 versus river sprats deserves consideration.* 



The location and area of the sprats' spawning ground, viz., 

 those frequenting our district, is not known to the fishermen 

 no more than that of the herrings. It is presumed to be seaward 

 by the eastern movement of the breeding fish. These just leave 

 us at the critical juncture of sexual maturity, accompanied by 

 the immature sprats, which have been temporarily sojourning 

 in the shallow brackish waters. There is a strong probability 

 of the spawning area being at only a very moderate distance 

 from land, possibly near or within territorial limits. Judging 

 by the sets of the tidal currents and likely action on buoyant 

 eggs, spawning may occur outside any portion of the North Sea 

 facing Essex. 



The opinion of fish-experts differs considerably. Professor 

 Mclntosh and Mastermanf believe that, from the place of cap- 

 ture of eggs in the Firth of Forth, the sprat spawns well up 

 the reaches of the estuaries. Cunningham J reasons from his 

 observations in the Plymouth neighbourhood that the sprats 

 go some distance oft shore in order to spawn, and Holt's 



* Mobius and Heincke evidently hold such opinion, inasmuch as in their account 

 of fishes of the Baltic, they state that there are two local races of sprats, spring and 

 autumn spawners, similar indeed to the herring races (Commis. Untersuch deutsch 

 meere, 1883). According to this view on our coast the larger fish caught at Dover 

 might represent sea sprats (autumn spawners), the smaller Thames sort to be equiva- 

 lent to brackish water form (spring spawners). But there is no decided testimony to 

 this effect. Hence, for the present we can but regard our S.E. Anglian sprats HS 

 exhibiting no prominent racial distinction. From the mode of fishing at Dover, the 

 sprats there caught, plausibly are a selection of the oldest, best conditioned, premature 

 breeders, the bulk of those frequenting the Thames ripening slower here taking their 

 inshore autumn visit in precedence. But, if such is the case, it tends to render ambig- 

 uous the significance of herring races. 



t Brit. Mar. Food-Fish, 1897 ; and llth and 16th Ann. Reps. S.F.B. for 1892 

 and 1896. 



I Marketable Mar. Fish, 1896. 



Jour. Mar. Biol. Assoc., April, 1898, Holt & Scott, Tabs. p. 156 onwards. 



