22O MARKETABLE BRITISH MARINE FISHES 



At Plymouth I have not found the young plaice of the year's 

 brood in any great abundance, but have taken some in Whitsand 

 Bay in June. The largest number obtained there in one day 

 by the shrimp trawl was thirty-nine, the depth at which they 

 were caught being 5 to 7 fathoms, and their lengths from ii to 

 2.V inches. Ten specimens obtained by a small seine from the 

 Cattewater in May measured from 4^ to 7 inches in length, and 

 these must be considered as representing the year-old fish. 

 Satisfactory evidence concerning the two-year-old fish is not 

 at present available, but as a very small proportion of females 

 are mature at 9 inches, and a large proportion immature, while 

 three-year-old fish are mostly mature, we may conclude that the 

 female plaice in the Channel at two years of age are about 

 9 inches and at three years about 1 3 inches long. 



More extensive observations on the sizes and growth of plaice 

 have been made in the North Sea. The great majority of the 

 small plaice taken by the hand-net shrimpers at Cleethorpes on 

 the shore of the Humber estuary at the end of April were found 

 to be from i to 2,\ inches long. These must be derived from 

 the spawning period immediately preceding. The experiments 

 on the rate of growth of flounders and plaice, which were made 

 in the Plymouth tanks, are sufficient to show that even Channel 

 plaice must be much more than 2 inches long on the average 

 when a year old, and the North Sea plaice being larger must 

 grow more quickly. We know that multitudes of newly trans- 

 formed young flounders are found in Mevagissey Harbour, in 

 Cornwall, in April. These are \ inch long, and after their trans- 

 formation grow rapidly. The plaice begins to spawn some weeks 

 before the flounder in the North Sea, and we know that millions 

 of plaice eggs are hatched there in January. We arc forced to the 

 conclusion therefore that the multitudes of small plaice found at 

 the mouth of the Humber at the end of April, whose average 

 length is 2 inches, are between three and four months old. With 

 them are taken a few larger plaice from 3 to 9 inches long, which 

 of course belong to the brood of the preceding year. The small 

 plaice are equally abundant in May and June, the swarms of 

 little fish appearing on the shore in succession as they are de- 

 veloped from the eggs shed in February and March. In later 

 months plaice of this size get scarcer because they grow larger, 

 but some specimens less than 3 inches in length were obtained 



