478 REPORT ON TRAWLING AND OTHER INVESTIGATIONS 



pretty regularly with the size of the fish, the immature fish from 

 7 to 10 inches having been found mostly inshore, and the fish of the 

 largest size-group only offshore. The smaller mature fish, i.e. from 

 11 to 14 inches, show, however, no such regularity when the season 

 of the year is taken into consideration. During the first half-year, 

 which, it will be borne in mind, included the winter period, twenty- 

 one fishes were recovered outside, as against only six inside the bay. 

 During the second half-year, extending from May to November, as 

 many of these fishes were recovered inside the bay as outside. 



The explanation of these facts becomes obvious upon a perusal of 

 the detailed tables in which the localities of capture are recorded in 

 chronological order. It will be seen that during October and November 

 the fish were mostly found in Start Bay, but during December, January, 

 and March most of the recoveries were made at considerable distances 

 from the bay in deep water, especially on the Spion Kop ground, 

 eight to ten miles off Beer Head, and on the Biscuit Dust ground, 

 some twelve to fifteen miles off the same headland. During April and 

 May the fish were still being recovered offshore, but nearer to the bay 

 than during the preceding period, the ground locally known as the 

 Corner being apparently the chief rendezvous of the fish at this 

 season.* During the latter part of May and the succeeding summer 

 months until October a considerable number of the fish were again 

 recovered inshore, mostly in Start Bay, but one at any rate (No. 293) 

 in Torbay. 



There can be no doubt, therefore, that a large proportion of the 

 plaice to be found in Start Bay make a periodical migration to the 

 offshore grounds on the approach of winter. Out of a total of twenty- 

 six fish recovered from December to April (both inclusive) four at most 

 were found in the bay, and two of these were taken on December 1st, 

 while the outward migration was still in progress. It has already been 

 seen that this migration is for the most part limited to the fishes of 

 11 inches and upwards, i.e. to those which have attained the average 

 size of maturity, and Dr. Kyle observed that the majority of the plaice 

 recovered offshore from January to April in this experiment were either 

 spawning or spent. 



Analysis of the records also shows that there is no one route of 

 migration, but rather a series of lines radiating fanwise from the bay 

 in directions varying between N.N.E. and E. The smaller mature 

 fish (between 11 and 13 inches) appear to have taken the shallower 

 gradients to the northward, ultimately reaching the Spion Kop ground 

 after passing Torbay and Teignmouth Bay (cf. Nos. 260, 279, 203, 

 210, 217, and 130). The larger fish, on the other hand, of about 15 



* Also of the trawlers, who follow the fish iu their migrations (cf. p. 440). 



