178 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



shrimps put aside, and we believe that they really wish to 

 preserve the life of as many of the immature fish caught 

 (which are not marketable, and are of no use to them) as 

 possible. And we have seen that the contents of the net 

 can be very rapidly sorted out. But in a large catch the 

 process is somewhat tedious, and as the deck space in a 

 shrimping boat is very limited, part of the catch may be 

 put into fish baskets unsorted, while the remainder is 

 being dealt with. In these circumstances the immature 

 fish in the reserved portion have little chance of life. 



It is clear that with long drags, with large catches, and 

 in warm weather the mortality among the immature fish 

 taken in the trawl is much greater. Considering all 

 things, there is not much doubt that of the immature fish 

 taken in the course of shrimp trawling, as at present 

 carried on, a large proportion must necessarily be 

 destroyed. 



We have made an attempt to determine the distribu- 

 tion from year to year of the four fishes considered above. 

 The average hauls for each fish for the third quarters of 

 each of the years 1893-9 have been calculated, and these 

 are the values compared. The third quarters (July, 

 August, September) are selected since those are the 

 periods during which the greater number of hauls were 

 made, and because they contain the maximum catches for 

 all the years and fishes considered. The values dealt 

 with, therefore, are those representing most probably the 

 condition of the fishery in each year. The results are 

 tabulated in Table VI., and they are represented graphi- 

 cally in the corresponding set of curves (VI.) on Plate C. 



During this period the average catches of plaice have 

 decreased from the maximum catch (2,045) in 1893 to the 

 minimum (176) in 1899. The decrease from 1893 to 

 1894 was very great. From 1895 to 1897 the catches were 



