EATE OF GROWTH OF SOME SEA FISHES. 243 



as seems more probable, that 90 per cent, of tlie sprats alone were 

 young larval forms. We may, I think without much error, assume 

 that the larval sprats were about two months old, as in the case of 

 the herring-, and it follows that the spawning of the sprats took 

 place chiefly in June, but occurred also in April and May. I do 

 not know at present to what extent the larger fish are separated 

 from the total catch of the stow-nets before the whitebait are sent 

 to market. But at any rate we know of only one spawning season 

 for sprats, which extends over three or four months, and, therefore, 

 the sprats taken in February, measuring 2 to 3 inches, were doubt- 

 less spawned between April and June in the previous year. Thus 

 they were seven to ten months old. Again we may reasonably argue 

 that the sprats taken in April and May before the larv£e of the 

 season had begun to appear, were derived from the previous year's 

 spawning, and were, therefore, about one year old, so that the 

 average size of year-old sprats is not much above 2^ inches. Un- 

 fortunately, the size of the year-old sprats taken in June and July 

 is not given ; those of 2j inches, taken in June must have been a 

 year old, but larger ones may have been picked out before the 

 samples of whitebait were taken. It is clear in any case that a 

 great number of sprats do not exceed 2| to 2^ inches at the age of 

 one year, but what the maximum growth may be is not determined. 



My own observations on young sprats at Plymouth are not 

 numerous; I have only obtained specimens on the following occa- 

 sions : 



November 21st, 1889, thirty-three specimens 5'5 to 6'6 cm. (2"2 

 to 2 "6 inches) taken in shrimp-trawl in Cawsand Bay. 



December 4th, 1889, four specimens, 5*7 to 6*2 cm. (2-2 to 2*4 

 inches) a sample from a large number killed in the Millbay Docks 

 by blasting under water when I was present. 



April 3rd, 1891, thirteen specimens, 8'5 to 9*8 cm. (3*3 to o"8 

 inches), caught in a bucket from the side of a boat off Eame Head ; 

 sample from a much larger number. 



At Plymouth the sprat commences to spawn at the end of January, 

 and the floating ova are found in February, March, and April, so 

 that I think the above specimens registered above were a little less 

 and a little more than a year old respectively. 



The only evidence at present available as to the size at Avhich 

 sprats become sexually mature is that of Matthews in his paper in 

 the second Report of the Scottish Fishery Board. He states that 

 of the sprats he obtained from the Forth, only one was 6 inches long, 

 and only two or three 5^ inches, all those near maturity measuring 

 4 to 41 inches. It appears, therefore, that small as the adult sprat 

 is it does not reach its mature size in one year, that it is 4 inches 



