18 



THE IMrOVERISHMENT OF THE SEA. 



surveys. On the other hand, by adopting such an extension of the 

 first period the averages could be less confidently claimed to represent 

 the condition of the areas immediately subsequent to tlie prohibition of 

 trawling. But it appears to me to be in any case indispensable that the 

 figures for the Forth and for St. Andrews Bay should be kept distinct, 

 as well as the figures for the different species of fish. 



I have therefore prepared a table (II.) of quinquennial averages 

 based upon these principles. The averages are not, it is true, based 

 upon the original numbers of fish taken in each haul of the trawl, but 

 upon the monthly averages per haul of the trawl published in each 

 year's report of the trawling experiments. In the case of St. Andrews 

 Bay the closed area embraced four trawling stations, so that each of the 

 monthly averages published for this area represented usually the mean 

 of four hauls of the trawl. The closed area of the Firth of Forth 

 embraced seven such stations, the monthly average therefore represent- 

 ing the mean of seven hauls. The figures in my table represent the 



Table II., showing the Average Monthly Numbers of Fiat-Fish -per Haul 

 of the Trawl taken by the " Garland " in the closed waters during 

 each (juinqucnnicd period, distinguishing the different areas and the 

 different kinds of Fish. 



St. Andrews Bay. 

 Plaice. 



