169 



The plaice for this experiment were captured on the 20th September, in the 

 Dornoch Firth (Moray Firth), where the " Goldseeker " had been working, and were 

 kept in tanks, after being marked, until 2.40 p.m. on the ?lst, when they were 

 liberated. 



The number recaptured was .36, or 36 per cent., which is a very small percentage 

 compared with other experiments ; the number of males was 12 (32-4 per cent.), 

 and the number of females, 24 (39-3 per cent.). 



Eleven of the males were of adult size on recapture, viz. from 33-4-42'7 cm., 

 with an average of 38"6 cm., compared with a range of from 31-37'5 cm., and an 

 average of 35-4 era. on liberation ; they were at liberty for from 21 to 666 days, the 

 mean being 359 days ; the distances migrated were from 5 to 42^ miles, the mean 

 being 27'3 miles and the average rate of travel '76 mile. 



Twenty of the females were of adult size, averaging 43-4 cm., and ranging from 

 38"5 to 50"5 cm., compared with an average of 40"2 cm., and a range of from 32*5 

 to 51 cm. on hberation ; they were at liberty for from 22 to 629 days, the mean 

 being 316 days, and travellecl from 45 to 123 miles, the average being 29*4 miles, 

 and the mean rate, "9 mile. Four of the females were under adult size, averaging 

 36'3 cm., as compared with 34-6 cm. ; they were at liberty for an average of 205 days, 

 and migrated a mean distance of 35*8 miles, the average rate, per 10 days, being 

 1*75 miles. 



The Extent and Direction of Migration. 



First Quarter. — None was recaptured in September. In October, 3 males and 

 3 females were got ; 2 of the males were found to the south and west, 1, measuring 

 37*5-37'2 cm., after 24 days, at a distance of 5 miles ; another, which was 3.3-.33'4 

 cm., after 19 days, at a distance of 22 miles, towards the Firth of Forth ; the third, 

 which measured 36*5-36 cm., after 21 days, 22 miles to the south and east ; one of 

 the females, measuring 44-43*3 cm., was recaptured, after 22 days, 11 miles to the 

 south-east ; another, of 40*5-40 cm., was taken at Aberdeen Bank, after 31 days, 

 at a distance of 30 miles northward ; these two females were described as " half 

 ripe," the remaining fish, which measured 34*5 cm. on hberation, but whose size 

 on recapture was not recorded, was taken, after 20 days, 11 miles to the south-west. 



Two females were taken in November, both "immature"; 1, measuring 

 38-38*5 cm., was caught south of Aberdeen Bank, at a distance of 25 miles, after 

 53 days ; the other, which measured 36*5-36*8 cm., was taken near the Bell Rock, 

 at a distance of 44 miles to the north and west, after 45 days. 



None was recaptured in December. 



Thus, in this quarter, 8 fishes, or 22*2 per cent., were taken, 3 (37*5 per cent.) 

 to the south and west, 2 to the south and east, 2 to the north and west, and 1 to 

 the north and east. 



Second Quarter. — In January 1913, a male, of 31-30*4 cm., was taken, after 121 

 days, 34| miles to the south and west, to the east of the Isle of May. 



A male and two females were recaptured in February, the male, of 36-36*5 cm., 

 and " nearly ripe," after 161 days, east of the Isle of May, at a distance of 30| miles 

 to the north and west ; one of the females was taken, after 150 days, 37 miles to the 

 north-east, at Aberdeen Bank ; it measured 42*5-43 cm., and was " nearly ripe " ; 

 the other, which was 51-50*5 cm., was got, after 151 days, south of Aberdeen Bank, 

 at a distance of 27 miles to the north and west. The condition of the reproductive 

 organ of this fish was not recorded. 



In March, a male and a female were recovered, the male, of 37*5-38*9 cm., and 

 " spawning " (" partly spent ") after 186 days, off St. Abb's Head, at a distance of 

 32 miles to the south and west, and the female, of 45-45*3 cm. (the condition of the 

 ovaries unrecorded), after 186 days, near Aberdeen Bank, at a distance of -30 miles 

 to the north and west. 

 6* 



