17;^ 



Sixteen of the males were of adult size on recapture, measuring from 33'3 to 

 39"7 cm., and averaging 35"9 cm., as compared with a range of from 32 to 37'5 cm., 

 and a mean of 35'4 cm. on liberation ; they were at liberty for from 3 to 495 days, 

 the mean being 134 days ; they migrated distances of from li- to 166 miles, the 

 average being 39"5 miles, and the mean rate of movement, 2"9 miles. Three of 

 the males were under the adult size on recovery, averaging 31*3 cm., as against 

 31 cm. on liberation ; they were free for a mean period of 100 days, and migrated 

 distances of from 12 to 84 miles, the average being 39 miles, and the mean rate of 

 travel 3* 8 miles. 



Four of the females were of adult size on recapture, averaging 41*8 cm., as 

 compared with 36*1 cm. on liberation ; they were at liberty for an average period 

 of 502"5 days, and migrated an average distance of 35"5 miles, the mean rate being 

 •8 mile. Seven were imder the adult size, ranging from 26"9 to 36-5 cm., and 

 avcT'aging 31'8 cm., as compared with a range of from 27"5 to 35"5 cm., and a mean 

 of 31*6 cm. on liberation ; they were free for from 22 to 117 days, the mean being 

 67 days ; they travelled distances of from 1| to 38 miles, the average being 13 miles, 

 and the mean rate, per 10 days, 1-9 miles. 



The Extent and Direction of Migration. 



First Quarter. — In December 1913, 5 males and 2 females were recaptured, 

 1 of the females at a distance of 12 miles to the south and east, 1 male 12 miles 

 to the north and east, and all the others to the south and west, near the shore, in 

 St. Andrews Bay, at distances of IJ and 2 miles. 



A female was captured in January 1914, 2^ miles to the south-west, also close 

 inshore, and in February, 2 males and 1 female were taken, all outside the Bay, 

 to the south and east, at the following distances : — -One male at 15 miles, the other 

 at 20 miles, and the female at 11 miles. 



In this quarter, 11 of the marked plaice, or 37*9 per cent., were recaptured, 

 6 (54-5 per cent.) to the south and west, 4 (36'4 per cent.) to the south and east, 

 and 1 to the north and east. 



Second Quarter. — Six males and 4 females were recaptured in March 1914, 4 of the 

 males and 2 of the females to the south and east, at distances of from 12 to 20 miles ; 

 1 female had moved up the coast, to the neighbourhood of Tod Head, a distance 

 of 38 miles to the north-east ; 1 female migrated round Fife Ness, to within the 

 mouth of the Firth of Forth, a distance of 13 miles, while a male was taken, after 

 99 days, in the Moray Firth, close to Tarbet Ness, a distance of 166 miles north- 

 wards, the rate of movement in this case being 16-7 miles per 10 days ; another 

 male was caught quite close to Rattray Head, after 92 days, a distance of 84 miles 

 to the northward ; its mean rate of movement was 9*1 miles per 10 days. 



In April, 2 males were taken, both at a distance of 12 miles to the south and east. 



None was recovered in May. 



Thus, in the second quartei, 12 fishes, or 41*4 per cent., were recaptured, 9 

 (75 per cent.) at a mean distance of 15 miles in the mean direction S. 57° E., and 

 3 (25 per cent.) at an average distance of 96 miles in the mean direction N. 47° E. 



Third Quarter. — ^A female and a male were recaptured in June, the female to 

 the eastwards, at a distance of 34 )niles, and the male in the Moray Firth, near 

 Berriedale Ness, at 159 n\iles distant, the mean rate of movement being 8'4 miles. 



None was taken in July and August, so that these 2 fish represent the total 

 for the third quarter (6'9 per cent.). 



Fourth Quarter. — Only 2 fish were taken in this quarter, namely, a male in 

 September. 7 miles east from the Bass Rock, at 19 miles distant to the south and east, 

 and another male in November, at a distance of 15 miles to the south and east. 



Within the 12 months after liberation, 27 of the marked plaice, or 93*1 per cent., 

 were recaptured, 16 (59-2 per cent.) to the south and east, 6 (22-2 per cent.) to 

 the south and west, and 5 (18^5 per cent.) to the north and east. 



The remaining 3 fishes of the experiment were taken as follows : — A male, in 

 April 1915, in the Moray Firth, close to Clyth Ness, at a distance of 158 utiles to 

 the northwards, a female, in July 1915, 26 miles to the south-east, south-east of 

 May Isle, and a female, in December 1916, after 1105 days, 30 miles E.S.E. of 

 Aberdeen, at a distance of 67 miles to the north and east. 



