236 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Sizes of the Fish Caught. 



As a general rule the fish caught on board the 

 " John Fell " and the Bailiffs' cutters are not measured 

 individually; only the largest and smallest fishes caught 

 are measured and recorded. On the present occasion, 

 however, an attempt was made to determine the character- 

 istic sizes of the plaice on the " large-plaice " grounds 

 which we were seeking. Hauls 2, 7, 8, 9 and 10 were 

 made on this ground ; it is obvious from an inspection of 

 the tables that Hauls 4, 5, G and 11 were made on a 

 ground which was different in respect of the distribution 

 of plaice. In Hauls 2, 7, 8, 9 and 10 all the plaice 

 caught were measured and the sizes recorded. 



The average size of the plaice taken in these hauls 

 is 1444 inches. But this number gives us no clear idea 

 of the sizes of the fishes present on the ground, and I 

 have therefore prepared a chart (p. 93) which shows the 

 numbers of plaice taken in these hauls arranged in groups 

 in which the size varies from inch to inch. 



This Chart shews that the greater number of fish 

 taken in the hauls selected were from 11J to 1G^ inches 

 in length. Few were caught which were smaller than 

 11^ inches or larger than 16^ inches. The " mode " or 

 predominant size of the plaice present is 13^ inches. If 

 the curve is " smoothed " the position of the " mode " 

 changes slightly and is about 14 inches. 



It should be observed that no one form of fishing 

 apparatus used alone gives a representative sample of 

 the fish present on a fishing ground. In the haul of the 

 shrimp trawl quoted it will be seen that only four plaice 

 were caught which were larger that six inches. This is 

 because the " draught " of water through the shrimp net 

 is so much less than through the 7-inch mesh employed 

 in the other hauls that very few large fishes were retained 



