qf the Fishery Board for Scotland. 



235 



middle districts are represented, showing that in these months the eggs 

 of the sprat have become very generally distributed over the inner waters 

 of the Firth. 



In 1893, from a study of the eggs of 1892 and 1893, the following 

 remark was made: — 'The eggs of the sprat . . . seem to be most 

 plentiful in the upper reaches of the Firth, and are abundant in the Inch- 

 keith district, but they become less common out to, and beyond the 

 Island of May' (11th Scottish Fishery Board Report, p. 251). A com- 

 parison, such as is here instituted, of the various stations through several 

 years, enables us to corroborate this and also to go further. 



The facts, point out most clearly that the sprat commences to spawn in 

 the middle stations, and shortly after, abundant spawning takes place in 

 the inner stations, Stations L, II., II., and IV., with Cross-section III., 

 throughout May, June, and July. Then the same characteristic is present 

 as in the whiting, the spawning commencing further out and con- 

 tinuing further inshore. There is no indication that sprats spawn to any 

 extent outside the Firth, in the extra-territorial waters. The eggs 

 spawned in the middle stations, in March and April, probably are drifted 

 up the Firth by the prevalent easterly winds, though a few find their 

 way outwards to Station IX. 



With an increasing mean temperature, as the season proceeds, and the 

 cessation of violent easterly winds, the eggs of the sprat can be laid with 

 impunity higher up the Firth. (Cunningham found the eggs of the 

 sprat to hatch in three days at a temperature not exactly stated, but 

 given as from 45° F. to 60° F.) These eggs, laid higher up, probably drift 

 to and fro for a few days with the changes of the tide and the softer 

 winds of the summer months, and they appear to be thus gradually 

 distributed over the surface of the *Firth. The eggs occurring in the 

 middle stations in the later part of the spawning-season, to judge by their 

 state of development and their relative numbers, have drifted outwards 

 from the inner stations. All the July observations are in one year, so 

 one cannot be too sure of a general rule here, but the facts would be 

 explained very well if the predominant winds during July were westerly, 

 or it might be that, in the absence of easterly winds, the resultant action 

 of the tide would be to carry the eggs out seawards. One of these 

 alternatives is, I thmk, capable of explaining the facts. 



We may thus state that (1) the spawning-areas of the sprat are first in 

 the middle stations, and shortly after in the inner district. (2) The 

 spawning-time extends from the end of March to about the middle of 

 August, in its extreme limits, with a maximum from mid-May to the end 

 of June. (3) After spawning, the eggs spawned in the middle stations, 

 as a whole, drift westwards up the Firth, and those spawned later in the 

 inner stations spread over the Forth out to the middle, and some even 

 to the outer stations. 



The sprat, therefore, forms the end of the series formed by the plaice, 

 cod, and haddock, whiting, and poor-cod. The accompanying diagram will 

 assist in the demonstration of this fact. Whereas the plaice, cod, and 

 haddock all spawn in the outer stations, but not further in, they also 

 spawn earliest of the series ; the three species also fall into a lesser series 

 in the same way, but less marked. The whiting (and poor-cod) spawn in 

 the outer stations, but rather later, and later still in the middle stations, 

 whilst the sprat do not probably spawn to any great extent in the extra- 

 territorial waters, but are slightly later than the whiting in the inner 

 stations. 



The sprat is essentially an estuarine fish, and, like many others of the 

 clupeoids, it shows a predilection for brackish or fresh water. The 



