55 



the distances migrated were from 4| to 90 miles, the average being 44"3 miles, and 

 the mean rate of movement 1"04 miles per 10 days. 



Four of the females were under the adult size, the average being 36' 1 cm., 

 compared with 33"6 cm. on Uberation ; the average period of freedom was 166 days ; 

 the distances migrated ranged from 4J to 113 miles, the mean being 46-3 miles, 

 and the mean rate of movement, 2'8 miles. 



The Extent and Direction of Migration. 



First Quarter. — A female, of 38-37'8 cm., was caught in June 1911, after 8 days, 

 at a distance of 18 miles to the east, off the Isle of May ; another female, of 32*5-33 

 cm., was taken in July, off St. Monans, in the Firth of Forth, a distance of 4 miles, 

 after 24 days ; in September, after 84 days, a third female, measuring 40 cm. on 

 Hberation, and of unrecorded size on recapture, was caught b)^ the " Goldseeker " 

 on Station VI. (where it was originally taken). This fish was again liberated 40 

 miles east of May Isle on 12th September (see page ). 



Only 3 fish, all females, were thus got in the first quarter, 2 within the Firth 

 of Forth. 



Second Quarter. — In November, after 136 days, a male, of 28'5-28'4 cm., was 

 taken, near Newhaven, in the Firth of Forth, at a distance of 15 miles. Two males 

 were recaptured in December, 1, measuring 32'5-35"5 cm., and " half -ripe," after 

 177 days, 26 miles to the north and east, north-west of the Bell Kock ; the second, 

 of 37-40"9 cm., and "nearly ripe," near Buchanness, 87 miles distant, after 185 

 days. 



Thus, only 3 fish were recaptured in this quarter, 1 within the Firth of Forth. 



Third Quarter. — In this quarter, which includes most of the spawning season, 

 9 marked plaice were recaptured. In January 1912, 2 females were taken, 1, of 

 34-38'9 cm., and " rather immature," at Aberdeen Bank, 63 miles distant, after 

 219 days ; the other, of 35"5-38"7 cm., was " spawning " (" partly spent '), and 

 was caught, after 225 days, near Buchanness, at a distance of 90 miles. 



Two females were also recaptured in February, 1 of 40"5-42'3 cm., and " partly 

 spent," to the east of the Isle of May, at a distance of 18 miles ; the other, measuring 

 45 cm. on liberation, somewhat farther to the north, at a distance of 25 miles, after 

 245 days ; its size on recapture and the condition of the ovaries were not recorded. 



Five were taken in March, a male and a female, off Pittenweem, 5 miles distant, 

 after 274 days and 260 days, respectively ; the male, measuring 34'5-38'2 cm., 

 is described as " immature " ; the female measured 37"5-41"2 cm., and was also 

 "immature." Two males were recaptured near Buchanness, at distances of 88 

 and 85 miles, after 257 and 265 days ; they measured 31"5-37'4 cm., and 40-44" 1 cm. 

 respectively, and both were " ripe." Another male was taken, after 272 days, 

 at a distance of 211 miles, off Strathie Point, on the north coast of Scotland ; it 

 also was " ripe." 



In this quarter, all the 9 fish went to the north alid east, for an average distance 

 of 66 miles, but 2 of them were taken in the Firth of Forth. 



Fourth Quarter. — Three were recovered in April, all to the north and east. A 

 female, of 32"5-37'2 cm., and " immature," was found, after 301 days, off Tod Head, 

 at a distance of 50 miles ; another female, of 42-43*6 cm., and " ripe," was taken, 

 after 302 days, to the north of Aberdeen Bank, at a distance of 78 miles ; a male, of 

 36-38'4 cm., and " spent," was got, after 305 days, at a distance of 67 miles, in 

 the same direction. 



In May 1912, after 331 days, a female, of 3r5-36'3 cm., and " immature," was 

 taken to the north-east of Rattray Point, at a distance of 113 miles. None was 

 taken in June. 



Four fish, therefore, were recovered in this quarter, and all had gone to the 

 north and east, for an average distance of 77 miles. 



In the 12 months following liberation, 19 of the fishes, or 70'4 per cent., were 

 recaptured, viz. 8 males (66*7 per cent.) and 11 females (73"3 per cent.). Seventeen 

 (89*5 per cent.) travelled to the north and east, and 1 each (5"2 per cent.) to the south 

 and east, and south and west. 



Of the remainder, 3 were taken in 1912, 3 in 1913, and 2 in 1914. Two were 

 found in July 1912, a male and a female, and both in the Moray Firth ; the male, 



