454 



REPORT ON TRAWLING AND OTHER INVESTIGATIONS 



hour, and the percentage frequencies of the fish of different size. The 

 limits between the various size-groups are the same as those previously 

 adopted by Mr. Holt, although the groups themselves are presented in 

 this report in slightly different form. The groups are as follows : — 



I. Unsaleable, or small immature — under 8 ins. in total length. 

 II. Immature medium-sized — from 8 ins. to 11 ins., both inclusive. 



III. Medium-sized mature — from 12 ins. to 14 ins. inclusive. 



IV. Large — 15 ins. and upwards. 



The study of Table F throws important light on various matters of 

 detail, especially on the succession of changes which took place in the 

 distribution of fish during the autumn and early winter of 1901 ; but 

 the relatively short duration of the hauls made in certain of the months 

 prevents the monthly summaries from possessing an equally representa- 

 tive character. It is accordingly desirable to summarise the results 

 still more closely in quarterly periods. This has been done in the 

 following table, which shows the average catch of plaice per hour for 

 the different size-groups, and also the percentage frequency of the 

 fish of these sizes during the five quarterly periods covered by the 

 investigations. 



Table V., showing, for Start Bay, the Average Catch of Plaice per Hour, 

 and the Percentage Frequency for each size, over all stations comhined, 

 for each quarterly period. 



Catch per Uour. 

 Total , 

 Season. 



July, Aug., Sept.,'01 

 Oct., Nov., Dec. „ 

 Jan., Feb. '02 



April, May, June „ 

 July, August ,, 



Total. 0-7" 8-11" 12-14" 15"+ 



19 

 20 

 11 

 18 

 23 



2 

 0-2 

 1 

 1 

 1 



3 

 3 



4 



4 



11 



10 

 4 



0-7'' 



9 

 1 

 10 

 4 

 3 



Percentages. 

 8-11" 12-14" 15"+ 



18 

 18 

 36 

 23 



47 



44 

 47 

 32 

 45 

 35 



29 

 34 

 22 

 28 

 15 



The investigations began in the summer period, and it will be seen 

 that the total catch of plaice, irrespective of size, increased slightly 

 during the autumn period, fell to a minimum in the winter, and then 

 increased steadily through the following spring and summer, the maxi- 

 mum in the summer season of 1902 being distinctly higher than during 

 the corresponding season of the previous year. 



The quarterly average catch of small plaice never exceeded two fish 

 for an hour's fishing. The immature medium-sized fish steadily increased 

 throughout the period of the investigations from an average catch of 

 3 per hour in the summer of 1901, to a catch of 11 per hour in the 

 summer of 1902. The mature medium-sized fish began in the previous 

 summer with an average abundance of 8 per hour, which increased to a 

 maximum of 10 per hour in the autumn, declining conspicuously to 



