492 REPORT ON TRAWLING AND OTITEK INVESTIGATIONS 



" The females are grouped under the same three headings as the males. 

 Maturing females mean those in which the ova are developing, as far 

 as the stage where a few ova are clear, i.e. ripe, but have not yet made 

 their way into the oviduct. Spawning females include all those which 

 have ripe ova in the oviduct, no matter what stage the ovary may 

 be in as regards depletion or emptiness. Spawned females are those in 

 which the ovary is flaccid, and very few, if any, ripe ova still remain. 



"The number of maturing females diminishes from 93 per cent, in 

 December to 65 per cent, on the 15th of January, and lastly to 16 per 

 cent, on the 10th of February. The spawning females are at no time 

 numerous, the highest percentage being 19 on the 15th of January. 

 The percentage of spawned females increases from 3"5 in December 

 to 16 on the 15th, 57 on the 25th of January, and 70 on the 10th of 

 February. 



" The maximum spawning period may be said to have been reached 

 when 50 per cent, of the specimens observed have spawned, and to 

 have passed when 70 per cent, is attained. On the other hand, if more 

 than 60 per cent, of the specimens have not yet begun to spawn it 

 is evident that the maximum spawning period has not yet arrived. 

 Consequently, the spawning of the plaice on the south-west coast of 

 England is at its height during the third and fourth weeks of January. 

 This holds good for the year under observation, viz. 1902, and if we 

 allow one week on either side for probable fluctuations in other years, 

 we conclude that the maximum spawning period lies between the third 

 week of January and the second week in February. 



" From the fact that a number of specimens had not yet begun to 

 spawn on the 10th of February we may conclude that the spawning 

 period is prolonged into March. No specimens were examined during 

 the latter month, but all those seen during the first fortnight of April 

 had finished spawning. 



" The number of specimens examined during the present investigations 

 is sufficiently large to test the suggestion made by Holt* that the 

 largest fish of a species spawn the earliest as a rule. The single 

 specimen which was found to have spawned in December was 40 cm. 

 (16 inches), and of the numbers examined in January the small (from 

 11 to 15 inches) and the large (over 15 inches) are equally distributed 

 amongst the maturing and spawning specimens, but the large clearly 

 preponderate amongst the spawned. Holt's conclusion is justified only 

 partly therefore, and the records for February point in the reverse 

 direction, as the largest specimens examined, 53, 55, and 65 cm. (21 to 

 26 inches), have not yet begun to spawn. Here, as elsewhere, con- 

 siderable variation occurs and definite conclusions are hard to find. 

 * Journ. M. B. A., vol. ii. p. 370. 



