141 



The plaice used in this experiment were taken on Station II., Firth of Forth 

 (Kirkcaldy Bay), on the same day as they were marked and Uberated. 



The number recaptured was 39, or 54'9 per cent., namely, 20 males (47-6 per cent.) 

 and 19 females (65"5 per cent.). Sixteen of the males were over adult size, ranging 

 from 33-3 to 45* 8 cm., and averaging 37-7 cm., as compared with a range of 30*5 to 

 46-5 cm., and a mean of 34'9 cm. on liberation ; the periods of freedom varied from 

 28 to 599 days, the mean being 269'5 days ; the distances migrated were from 6-5 

 to 187 miles, and the mean rate of movement, per 10 days, was r4 miles. Of the 

 four recaptured males under adult size, the average was 30"2 cm., compared with 

 28-7 cm. on liberation ; they travelled a mean distance of 43'8 miles in an average 

 period of 184 days, at a mean rate of 2-4 miles per 10 days. 



Nine of the females were over the adult size on recapture, the range being from 

 38-5 to 44 cm., and the average size 41*5 cm., as compared with 29 to 44 cm. and an 

 average of 35'4 cm., on liberation ; they were absent for from 19 to 761 days, the 

 mean being 503 days ; their range of miles travelled was 13 to 83, averaging 43 miles ; 

 they had travelled at a mean rate of '85 mile per 10 days. 



Ten were under the adult size, namely, from 27 to 33*2 cm., the mean size being 

 30'8 cm., as compared with 26'5 to 33 cm. and an average of 29*7 cm. on hberation ; 

 the periods of freedom varied from 42 to 379 days, averaging 132'4 days, and they 

 travelled journeys of from 6 to 59 miles, the mean being 30*2 miles, and the average 

 rate of movement, per 10 days, 2'3 miles. 



The Extent and Direction op Migration. 



First Quarter. — In July (which is here included in this quarter), 1 male, measur- 

 ing 34-33'3 cm., was taken, after 15 days, 10 miles to the westward, in the direction 

 of the Isle of May. 



In August, 1 male and 3 females were recovered ; the male, of 37-36'9 cm., was 

 taken, after 28 days, to the east of the Bell Rock, at a distance of 6| miles in a 

 north-easterly direction ; 1 of the females, of 39-38*6 cm., was caught, after 19 

 days, to the south-east of Aberdeen, at 23 miles distant ; another, measuring 26*5- 

 27 cm., was taken, near Buchan Ness, at a distance of 59 miles ; the third female, 

 of 32-32*7 cm., was recaptured, after 46 days, offshore, to the south-east of Long- 

 stone Light, at a distance of 56 miles. 



Five fish were recaptured in September, 2 males and 3 females ; 1 of the males, 

 of 46-5-45"8 cm., and described as " about half ripe," was taken, after 57 days, 

 12 miles to the south and west ; the other male was caught at the same place, on the 

 same day, and measured 33*5-35 cm., and was " immature " ; 1 of the females, 

 measuring 33-32-1 cm., was recaptured, after 71 days, 12 miles to the southwards ; 

 another female, of 28-29*2 cm., was got, after 77 days, to the south-east of the Bell 

 Rock, at a distance of 19 miles ; the third female, measuring 29*5-31*5 cm., was 

 recovered, after 68 days, near the Isle of May, at a distance of 33 miles to the 

 westward. 



In this quarter, therefore, 10 fishes, or 25*6 per cent, of the total recaptured, 

 were obtained, namely, 4 males (20 per cent.) and 6 females (31*6 per ce:it.). 



Second Quarter. — In October, 4 of the marked plaice were recovered, 3 males and 

 1 female ; the female, measuring 30*5-32*3 cm., was taken, after 106 days, off Fife 

 Ness, at a distance of 34 miles ; one of the males, measuring 32*5-34*5 cm., was 

 recovered, after 82 days, east of the Isle of May, at a distance of 24 miles from the 

 Station ; another, of 30*5-30*5 cm., was taken, after 84 days, 24 miles to the west- 

 ward, off Fife Ness ; the third male, of 35-35*2 cm., was got, after 100 days, 31 miles 

 to the south and west, towards the mouth of the Firth of Forth. 



In November, a female, measuring 44-43*8 cm., was recaptured, after 139 days, 

 offshore, near Aberdeen Bank, at a distance of 40 iniles. 



In December, two males and two females were caught, but the position of one of 

 the males and of one of the females was not recorded ; the other male, which 

 measured 32-37 cm., was taken, after 144 days, at a distance of 24 miles to the 

 south and west, towards the mouth of the Firth of Forth ; the female, of 29*5-30*2 

 cm., was caught, after 154 days. 6 miles to the north and west. 



