232 



Sinclair Bay, near Wick, 89 niiles to the south and west, and the other measuring 

 33-5-34-1 cm., caught in March 1911, near Buchan Ness, 130 miles to the south 

 and west. One female, which measured 38-38-2 cm., taken in January 1911, south- 

 east of Noss Head, 88 miles to the south and west, was " immature." 



EXPERIMENT IV. 



16th September 1910. 



In this experiment, 30 plaice, taken by the ," Goldseeker " in the locality, 

 were liberated 13 miles S.E. by E. J E. of Fair Isle (59° 26' N. ; 1° 14' W.), com- 

 prising 10 males and 20 females. The males measured from 33 to 40 cms., and all 

 were of adult size ; the females ranged from 33-5 to 43-5 cms., and 7 were under 

 adult size on liberation. 



The numbers Kberated and recaptured, arranged in 5-cm. groups, were as 



follows : — 



cm. cm. cm. cm. cm. 



2.5-30-5 31-35-5 30-40-5 41-45-5 46-50-5 Total. 



F. Lib. ... — 3 14 3 — 20 



F. Kecap. . . — 2 8 2 — 12 



M. Lib. ... — 6 4 — — 10 



M. Recap. . . — 3 4 — — 7 



The number recaptured was 19, or 63-3 per cent., 7 males (70 per cent.) and 

 12 females (60 per cent.). 



Six of the males were of adult size on recapture, averaging 38*2 cm., as compared 

 with 37-5 cm. when Hberated ; they were at liberty for from 137 to 630 days, the 

 mean being 301 days ; they migrated distances of from 1 to 134 miles, the mean 

 being 78-8 miles, and the mean rate was 2-6 miles. Eleven of the females were of 

 adult size when recaptured, averaging 42-6 cm. as against 39-4 cm. ; they were at 

 liberty for from 45 to 417 days, the mean being 233 days ; they migrated distances 

 of from 4 to 167 miles, the mean being 45-8 miles, and the mean rate 1-4 miles. 



The Extent and Direction op Migration. 



First Quarter. — In October, 2 females were taken, one 18 miles to the south 

 and west, and the other 42 miles to the north and west, to the north of the Shet- 

 lands. A female was caught in November, east south-east of Sumburgh Head, 

 32 miles to the north and east. 



In this quarter these were the only 3 fish obtained (15*8 per cent.). 



Second Quarter. — In January, a male was recaptured 1 mile off Whitehills, near 

 Banff, in the Moray Firth, 113 miles to the south and west. 



Third Quarter. — Two females and a male were taken in April, a male 1 mile 

 to the north and east, and both females to the south and west, near together, at 

 35 and 36 miles east of the Orkneys. 



In May, a male and 2 females were recaptured, the male 46 miles to the north 

 and west, near Foula, and both females to the south and west, 1 east of the Orkneys, 

 at a distance of 53 miles, and the other off the north coast of Scotland, 10 miles 

 north-east of Whiten Head, 105 miles distant. 



In this quarter, 6, or 31-6 per cent., were recaptured, 4 (66-6 per cent.) to the 

 south and west, and 1 each to the north and east, and north and west. 



Fourth Quarter. — Two males and 2 females were taken in June, 1 of the females 

 5| miles to the west, all the others to the south and west, a female at a distance 

 of 32 miles east of the Orkneys ; 1 male in the Moray Firth, north and west of 

 Banff, at 106 miles, and the other male 4 miles east -north -east of Cape Wrath, on 

 the west coast, at a distance of 134 miles. 



These were all the fish taken in this quarter. 



In the 12 months, 14 fish, or 73-7 per cent., were recaptured ; 9 (64-3 per cent.) 

 to the south and west ; 2 each to the north-east and north-west, and 1 to the west. 

 The date of recapture of 2 other fish was not ascertained ; 1, a female, was taken 



