464 



REPORT ON TRAWLING AND OTHER INVESTIGATIONS 



experiments on this point. Why the larger fish should have displayed 

 this disinclination to enter the hay remains unexplained. It is not 

 improhahle that variations in the " foulness " of the ground in Torbay 

 may be largely responsible for such fluctuations in the numbers of 

 summer immigrants, as well as for emigrations of the normal inhabit- 

 ants of the bay, as suggested below by Dr. Kyle in the case of Teign- 

 inouth Bay. 



We may now compare these results witli the distriliution of the 

 different sizes of plaice in Torbay, as recorded by Mr. Holt for 1895-8. 



Table XII., shoicing the Catch j^er Hour and the Percentage Frequency of 

 Plaice of different sizes in Torhay during 1895-8, based on the 

 records of the " Thistle " and " Busy Bee " {compiled from Mr. Holt's 

 report). 



Bearing in mind the reservations previously expressed with regard 

 to the comparability of these records (p. 456), it is nevertheless apparent 

 that in July, 1898, the Busy Bee, in spite of its somewhat smaller catching 

 power, caught a larger average number of plaice from 8 to 11 inches 

 than did the Oithona in the summer season of either 1901 or 1902, and 

 that the higher catch of the Oithona in 1902 more closely approached 

 the Busy Bee's record than did the smaller catch of 1901. We may 

 therefore conclude that in Torbay, as in Start Bay, the numbers of 

 plaice of this size were abnormally low in 1901, but were increasing 

 to more normal proportions in the course of 1902. The June records of 

 the Busy Bee in 1897 suggest the further point that the smallest plaice 

 (especially the 5-inch fish) were more abundant in that year than sub- 

 sequently. As these fish, after one year's growth, would form the 

 greater part of the 8-to-l 1-inch group in the succeeding year (see 

 p. 489), it appears to be in the highest degree probable that the observed 

 abundance of the 8-to-l 1-inch plaice in July, 1898, is traceable to the 

 corresponding abundance of the smallest plaice in the preceding year. 

 In a similar manner the increased abundance of the larger immature 

 plaice in the summer of 1902 was preceded, according to the Oithona's 

 records (Tables XI. and D), by a high average catch of the smallest fish 

 (4 and 5 inches) throughout the preceding autumn and winter, an average 

 much higher, it will be noted, than the Busy Bee's catches in July and 

 November, and almost as higli as the Thistle's catch in January to March. 



