287 



24 miles to the south and east ; 1 was got in March 1913, 18 miles to the north and 

 west, south of Clyth Ness, and 1 in March 1915, 39 miles to the south and west, at 

 the entrance to the Dornoch Firth ; the fourth was recovered in February 1914, 

 20 miles to the west, south-east of Berriedale Ness. One was described as 

 " ripe " ; it was taken in December 1912, off Dunnet Head, on the north coast, at a 

 distance of 58 miles to the north and west. One, recaptured in January 1913, near 

 Tiirbet Ness, 37 miles to the south and west, was " nearly ripe." 



Females. — The condition of the ovaries was described in 4 of the 12 recaptured. 

 All were " immature." 



EXPERIMENT VIII. 



27th March 1913. 



In this experiment, 30 plaice were marked and hberated at 58° 10' N. ; 2° 35' W., 

 viz. 9 males and 21 females. The males measured from 31-5 to 365 cm., and 

 2 were under adult size. The females measured from 32 to 44-5 cm., and 15 

 were under adult size. 



The numbers liberated and recaptured, arranged in 5-cm. groups, were as 

 follows : — 



cm. cm. cm. 



31-35-5 36-40-5 41-45-5 Total. 



F. Lib. ... 5 13 3 21 



F. Eecap. ... 2 2 1 5 



M.Lib. ... 8 1 — 9 



M. Recap. ... 4 1 — 5 



The fish used were taken by the " Goldseeker " in the Firth of Forth, at Station 

 VI., off St. Monans, on the afternoon of the 26th March, and they were liberated, 

 after 21 hours in running water, all being in good condition. 



The number recaptured was 10, or 33*3 per cent., 5 males (55-5 per cent.) and 5 

 fpmales (23-8 pei cent.). Four of the males were of adult size, averaging 38-3 cm. 

 as against 33-6 cm. on liberation ; they were at liberty for a mean period of 329 

 days, and migrated from 22 to 92 miles, the average being 65-2 miles, and the mean 

 rate was 2 miles. Three of the females were of adult size, averaging 42-1 cm., as 

 compared with 39-3 cm. ; their periods of freedom averaged 177 days, and they 

 travelled from 16 to 20 miles, the mean being 18 miles, and the average rate -9 

 mile. 



The Extent and Direction op Migration. 



A male and a female were recaptured in April, the male 10 miles to the north 

 and east, and the female 13 miles to the north and west, off Berriedale Ness, A 

 female was taken in June. 1 7 miles to the north and east, and in July another female 

 was found, but its exact position was not ascertained. In September, a male 

 went 18 miles W.N.W. of Stack Skerry (Lat. 59° 3' N.; Long. 5° 5' W.), 92* miles 

 to the north and west. Two females were taken in October, 1, 16 miles to the 

 south and west, and the other 20 miles to the north and east. 



In March 1914, 2 males were recaptured, 1 by a foreign frawler in the " Moray 

 Firth," and the other 8 miles E. by N. of Sule Skerry (Lat. 59° 15' N.; Long. 

 4° 30' W.) 80 iniles to the north and west. The last fish to be recaptured was a male, 

 in June 1914, 22 miles to the north and west. 



Distances travelled. — None was taken under 10 miles from the station, but betTcen 

 10 and 20 miles there were 4, or 50 per cent., 1 male and 3 females, the male 

 and 1 of the females to the north and east, a female to the north and west, and 1 to 

 the south and west. Two were caught between 20 and 50 miles, a male 22 miles 

 to the north and west, and a female 20 miles to the north and east. Two migrated 

 between 50 and 100 miles, both males, which moved to the north and then west- 

 wards, distances of 80 and 92^ miles. 



