66 



females were under the adult size on recapture, ranging from 32-2 to 37-1 cm., 

 the mean being 35-5 cm., compared with from 30 to 34-5 cm., and an average 

 of 324 cm. on liberation ; the fish were at Uberty from 9 to 492 days, the average 

 being 212 days ; the distances migrated ranged from 2| to 136 miles, averaging 

 28-4 miles, and the mean rate of movement per 10 days was 1-34 miles. 



The Extent and Direction op Migration. 



First Quarter. — In May 1912, 4 plaice were recaptured, 1 male and 3 females, 

 all within the Firth of Forth, 3 near Ehe, about 2 miles distant, and 1 off Pitten- 

 weem, at a distance of 4 miles. One of the females, measuring 44-44-3 cm., got 

 off Pittenweem, was " spent " ; all the others were " immature." In June a 

 female, of 39-5-39-4 cm., was taken 24 miles distant, to the east of the Isle of 

 May. In July 4 females were caught, all eastwards of the Firth of Forth, at 

 distances from the station of 11, 12, 17, and 24 miles ; 1, measuring 42-5-44-1 cm., 

 was "half-ripe," and all the others "immature." The number recaptured in the 

 first 3 months after liberation was, therefore, 9, or 12-7 per cent., 4 within the 

 hmits of the Forth, and 5 off the mouth of the Forth. 



Second Quarter.— In August 1912, 2 fishes were recaptured, a male, of 33-5- 

 36"5 cm., to the north-east of the Isle of May, at a distance of 16 miles, after 

 114 days, and a female, of 40-5 cm., when hberated, but of unknown size when 

 recaptured, which was taken to the south-east of St. Abb's Head, at a distance 

 of 54 miles, after 120 days. Four, all males, were taken in September, 2 at 16 

 and 17 miles distant, to the east of the Isle of May, after 140 and 134 days, and 

 measuring 36-5-38-8 cm., and 36-37-5 cm. respectively ; 1, of 36-38-6 cm. 

 (described as " nearly ripe "), was caught 34 miles to the north-east after 145 days, 

 and another, measuring 35-5-37-7 cm., in the same direction, at a distance of 

 68 miles, after 150 days. Three were recaptured in October 1912, 1 male and 

 2 females. The male, of 33-5-38-5 cm., and described as "half -ripe," was taken 

 32 miles to the north-east after 177 days ; 1 of the females, of 32-35-5 cm., and 

 therefore under adult size was caught, after 184 days, 15 miles to the north and 

 east ; the other, measuring 34-5-38-3 cm., was found, after 179 days, at a distance 

 of 77 miles to the north-east, off Aberdeen. 



In this quarter, therefore, the total number recaptured was 9, or 12-7 per 

 cent., and all were taken outside the Firth of Forth, 8, or 88-8 per cent., to the 

 north and east, and 1 to the south and east. 



Third Quarter. — A female, of 38-41-3 cm., and described as "nearly ripe," 

 was recaptured in November, after 218 days, east of the Isle of May, at a distance 

 of 16-5 miles ; the rate of movement was 41-3 miles per 10 days. In December 

 4 marked plaice were taken, 2 males and 2 females, 3 to the north-east, and 1 

 far to the south-east. One of the males, measuring 35-39-1 cm., was caught, 

 after 250 days, 71 miles to the northwards, off Aberdeen Bay ; another, of 35- 

 39-2 cm., and " nearly ripe," was caught off Banff, in the Moray Firth, at a distance 

 of 134 miles, after 243 days. One of the females, measuring 33-36-9 cm., and 

 thus under adult size, was taken, after 222 days, 38 miles northwards, close in, 

 near Montrose ; it was described as " nearly ripe." The other female, measuring 

 45-47-5 cm., and also "nearly ripe," was caught, after 237 days, at a point 2 miles 

 north-east of the E. Goodwin Light (51° 17' N. ; 1° 30' E.)" a distance of about 

 357 miles ; this fish was taken by a Kamsgate smack, and landed at Ramsgate, 

 and it is of much interest, as showing that plaice from the Firth of Forth may, at 

 rare intervals, migrate to the southern part of the North Sea. All these fish had 

 moved with rapidity, the one taken on the Goodwin Sands showing an average 

 rate of 15 miles per 10 days, the male caught in the Moray Firth an average rate 

 of 5-5 miles, the male taken at Aberdeen Bay a rate of 2-8 miles, and the female 

 caught at Montrose an average rate of 1-7 miles. In January 1913, 3 males were 

 captured, all to the northwards, 2 in the Moray Firth, and 1 south-east of the 

 Pentland Skerries. The 2 caught in the Moray Firth were taken close together, 

 north-east of Tarbet Ness, at distances of 155 and 156 miles each, after 281 days ; 

 they measured respectively 34-37 cm., and 35-5-37-4 cm., and botli were " spawn- 

 ing." The male caught off the Pentland Skerries, at a distance of 164 miles, 

 after, 268 days measuring .34-5-37-3 cm., and was " nearly ripe." The rates of 



