277 



The Extent and Direction of Migration. 



First Quarter. — Li May, 2 females were recaptured, the position of 1 being 

 vaguely indicated as " Moray Firth " ; the other was taken 20 miles to the north- 

 east, off Noss Head. 



Li June, a female was recovered, the place of capture being still more vague, 

 namely, " North Sea " ; it was landed at Geestemiinde. 



Second Quarter. — In September, 5 females were taken, the position of 3 being 

 given as " Moray Firth " ; the fourth was found 20 miles to the north-east, off 

 Noss Head, and the fifth, 36 miles to the south and west, at Burghead. 



Li October, a female was recaptured in Cromarty Firth, at 45 miles distant 

 to the south and west. 



Third Quarter. — Li December, a female was recaptured in the " Moray Firth," 

 and landed at a foreign port. 



Fourth Quarter. — In February 1912, a male was taken 10 miles to the north 

 and west, off Clythness, and a female was got on Smith Bank, in the place where it 

 was h berated. 



A male was recaptured in March 1912, 36 miles to the south and west, in the 

 Dornoch Firth. 



Thus, within the 12 months following liberation, 13 of the fish, or 92-8 per cent., 

 were recaptured, the positions being known for only six, or 42*8 per cent. 



The 1 remaining fish from the experiment was got in September 191 2, in Burghead 

 Bay, 35 miles to the south and west. 



Distances travelled. — Only 1 fish went a distance of 10 miles, and none was 

 found between 10 and 20 miles. Six fish (85-7 per cent.) were recaptured at distances 

 of from 20 to 45 miles, 2 males and 4 females. The males and 2 of the females 

 were found to the south and west, the other 2 females to the north and east. 



Maturity. 



Males. — The condition of the testes was recorded for 2 of the males. One was 

 " ripe" ; it was taken in February 1912, 10 miles to the north-w^st. The other 

 was "very immature," although captured in March 1912, and measuring 29-34 '5 

 cm. ; it was taken in the Dornoch Firth, 36 miles to the westward. 



Females. —The condition of the ovaries was ascertained in 4 of the 1 1 recaptured. 

 One, taken in September 1911, 20 miles to the north and east, was described as 

 " half ripe." All the others were " immature." 



experiment IV. 

 19th September 1911. 



In this experiment, 101 plaice were marked and liberated, viz. 36 males, 63 

 females, and 2 whose sexes were not ascertained. The males measured from 29 

 to 48 cm., and 5 were under adult size on liberation. The females ranged from 

 29 to 76 cm., and 15 were under adult size on liberation. 



The numbers liberated and recaptured, arranged in 5-cm. groups, are as 

 follows : — 



Some of the fish used in this experiment were recaptured by the " Goldseeker " 

 in Dornoch Firth, and marked, on the 18th between 5. .30 and 6 p.m., but most were 

 taken on the 19th in Burghead Bay ; they were liberated about 6 p.m. on the 19th. 



