KEPORT OF THE COUNCIL. 61 



4. The average rate of growth of plaice in the southern part 



of the North Sea at different ages, and the difference 

 between the sexes in this respect. 



5. The relative numerical proportions of the two sexes at 



successive ages. 



6. The age and size at first maturity. 



Food of Fishes. The stomachs of over 10,000 fishes belonging to 

 34 species have now been examined, and a second detailed report on 

 the food of fishes is in the press. 



Among the more important observations it contains may be mentioned 

 those on 



1. The predominant extent to which Crustacea serve as food 



for almost all useful species of fish during their earliest 

 stages, and the degree to which the diflerent species of 

 fish diverge in their selection of food as they grow older. 



2. The cessation of feeding by flat-fish, especially plaice, 



during the winter months, and the relation of this 

 phenomenon to spawning and other conditions. 

 4. The competition between plaice, haddock, and dabs for 

 mollusean food, especially on the Dogger Bank, and the 

 great destruction of mollusean fry by these species, 

 particularly by the haddock. 



Bottom Fauna and Bottom Deposits. — The analysis of this 

 material has made continual progress, and the results are in process of 

 collation. 



Herring Investigations. — Several additional samples, each of 100 

 fish, including one sample from the Cornish coast, have been examined 

 in conformity with the scheme described last year. All the samples 

 show a high degree of uniformity as regards the number of vertebrae. 



C. FISHERMEN'S EECOEDS. 



This branch of the work has been continued on the same lines and 

 on the same scale as hitherto. 



The records of Lowestoft trawling smacks so far as concerns the 

 catch of plaice and soles have been worked up for each of the past four 

 years so as to show the average catch per haul for each month in 

 succession, and for each of nine grounds into which the total area has 

 been subdivided. 



The results show clearly the seasonal fluctuations in the catch 

 on different grounds, and harmonize remarkably well with the results 

 of the Huxley's marking and other experiments in the same region. 



