80 



I. Discussion of the Statistics. 

 We have taken advantage, however, of the ten years 

 series of observations to split up the whole period into two 

 quinquennial parts, and to compare the average catches 

 of immature iishes and shrimps during the first period 

 (1893-7), with those of the second (1898-1902). It is 

 hoped that by this treatment of the figures, irregularities 

 due to conditions referred to later, are smoothed out, and 

 that the data really represent the average condition of the 

 grounds during the two five-yearly periods. The greater 

 number of hauls have generally been made during the 

 three months July, August and September, and as it is 

 during those months that fish are most numerous on the 

 grounds, they are the most convenient periods of the years 

 to compare. But to confirm the results, the 4th quarters 

 of the years, October-December, in the case of the 

 Blackpool grounds, and the 2nd quarters, April-June, are 

 also compared. 



Blackpool Closed Grounds. 

 Average catches of immature fishes and shrimps made 

 with a shrimp trawl during the 3rd and 4th quarters of 

 the two quinquennial periods, 1893-7 and 1898-1902. 



