248 



The 2 males were recaptured to the north-east of the Bell Kock, not far apart, 

 1 at a distance of 65 and the other at 69 miles to the north and west. 



Within the first 12 months after liberation, then, 16 fishes, or 55'2 pe rcent., 

 were recaptured, 7 (43"75 per cent.) to the north and west, and 5 (31 "25 per cent.) 

 to the south and west. 



Of the remainder, 7 were taken in 1913, and 6 in 1914. Two females were 

 recovered in June 1913, both off Aberdeen, not far apart, at distances of 60 and 63 

 miles respectively to the north and west. A female was recaptured in July, 132 

 miles to the south and west, 2 miles S.W./W. | S. of the Tees Buoy. A male was 

 taken in September, south-east of Aberdeen, at a distance of 39| miles to the 

 north and west. In October, 2 males and ] female were caught, the female near 

 the place of liberation, at a distance of 4 miles to the south and east ; 1 of the males 

 had migrated westward for a distance of 88 miles, and was recaptured east of the 

 Isle of May ; the other was caught to the south-east of Buchanness, at a distance of 

 40 miles to the north and v^est. 



In April 1914, a male was taken to the east of Aberdeen, at a distance of 48 miles 

 to the north and west, " immature." A male and a female were recaptured in July, 

 the male 50 miles to the N.W., south-east of Aberdeen, the female 39 miles to the 

 west and north. In August, a male was recaptured 21 miles to the north and west 

 of the station. In September, a male was got north-east of May Isle, at a distance 

 of 82 miles. The last fish to be recovered in the experiment was a female, measuring 

 33 cm. on liberation, but of unknown size on recapture, which was taken in December 

 1914, after 912 days, off Banff, in the Moray Firth, at a distance of 119 miles. 



The chart shows that almost all these fish migrated towards the shore from the 

 deeper water, where they were liberated, to the shallower water near the coast, 

 and with a rapidity much greater than usual. The only exceptions are 3, 1 which 

 moved to the north and east, and 2 which went to the south and east. 



Distances travelled — 10 miles and under. — Only 1 fish, or 3"4 per cent., was 

 taken under 10 miles — a female, which was found 4 miles to the east and south. 

 This, indeed, was the only fish recaptured within 20 miles of the station. 



20 to 50 miles. — Nine, or 31 per cent., were taken at distances of from 21 to 50 

 miles, 7 males (50 per cent.), with an average of 41 '3 miles, and 2 females (13"3 per 

 cent.), with a mean distance of 40*7 miles. They all migrated towards the coast, 

 the 2 females and 6 of the males to the north and west, and 1 of the males to the 

 south and west. 



50 to 100 miles. — Sixteen fishes, or 55*2 per cent., were found at distances of 

 from 52 to 100 miles, 7 males (50 per cent.), with an average of 77*9 miles, and 9 

 females (60 per cent.), with an average distance of 69*7 miles. With 2 exceptions, 

 they all travelled towards the coast, to the west or north-west, but 4 of the females 

 went to the south and west ; of the 2 exceptions referred to, 1 went north and east.. 

 and was recaptured far offshore, to the north and east of Buchanness, and the 

 other went south and east, also offshore. 



Over 100 miles. — Three of the females were taken at distances over 100 miles, 

 1 in the Firth of Forth, 117 miles to the west, another, in the Moray Firth, off Banff, 

 at a distance of 119 miles, and the third, off the Tees, 132 miles to the south and 

 west. 



Maturity. 



Males. — The condition of the testes in 12 of the 14 recaptured was ascertained. 

 They were all " immature " ; 9 were above adult size, but only 1 was recaptured 

 within the limits of the spawning season, viz. on 21st April 1914, at a distance of 

 48 miles to the north and west, off the coast of Aberdeen ; it measured 30'5~36'5 cm. 



Females. — The condition of the ovaries was ascertained in only 9 of the 15 

 females recovered. None was " spawning " or " ripe " ; 1, of 54— 53*3 cm., taken 

 in July 1912, near Tod Head, 80 miles to the west and north, was " spent." All 

 the others were " immature," and none was taken within the limits of the spawning 

 season. 



EXPERIMENT II. 



13th June 1913. 



In this experiment, 101 plaice were marked and liberated, viz. 42 males, 58 

 females, and 1 whose sex was not determined. The males ranged in size from 



