299 



Maturity. 



Males. — The condition of the testes was ascertained in 20 of the 28 recaptured. 

 Seven were described as " spawming " ; 3 were taken in February 1914, all to the 

 north and east, at 11, 14, and 28 miles respectively ; 2 in Marcb 1914, 1, 16 miles 

 to the north and west, and 1,16 miles to the north and east ; the remaining 2 were 

 recaptured in February 1915, 1, 13| miles to the north and west, and the other 27 

 miles to the north and east ; all but 2 of these spawning males were taken at the 

 mouth of the Dornoch Firth, the two exceptions being got farther along the coast. 

 Six were "ripe," 1 captured in January 1914, at an unspecified locality, in the 

 Moray Firth, 2 in February 1914, 1, 24 miles and the other 37 miles to the north 

 and east, 2 in March 1914, off Burghead, and the remaining fish in April 1914, 

 38 miles to the north and east. One was described as " spent " ; it was caught 

 in February 1914, 11 miles to the north and west. Another, taken in December 

 1914, on the north coast, off Whiten Head, was " nearly ripe." 



Females- The condition of the ovaries was determined in 20 of the 25 females 

 recaptured. Two were " spawning," 1 taken in February 1914, 11 miles to the north 

 and east, at the mouth of the Dornoch Firth, and the other in March 1914, off 

 ^Vhiten Head, on the north coast, at a distance of 105 miles. Four were described 

 as " ripe," 1 caught in July 1914, at an unknown place ; another, in February 

 1914, on the north coast, off Side Skerry, at a distance of 106 miles ; a third in 

 April 1914, also off Sule Skerry, at a distance of 107 miles ; and the fourth, in 

 December 1913, 12 miles to the northward, at the mouth of the Dornoch Firth. 

 Eleven were said to be " spent " ; all but 1 were recaptured in the locality, at 

 distances between 2 and 5 miles, the exception being taken at the mouth of the 

 Dornoch Firth, at a distance of 16| miles ; another female, caught in December 

 1913, at the mouth of the Dornoch Firth, was described as " not qi^ite ripe." 



Experiment at Nairn Bay, Station II. 

 IWi November 1913. 



On 12th November 1913, 50 ir.arked plaice, comprising 25 males and 25 females, 

 were liberated in Nairn Bay, in the Moray Firth (Lat. 57° 37' N. ; Long. 3° 54' W.). 

 The males ranged in size from 24 "5 to 44 cm., and 10 were under adult size on 

 liberation. The females were from 26 to 58'5 cm., and 17, when liberated, were 

 under adult size. These fish were captured partly at Burghead Bay and partly at 

 Nairn Bay, on the same day. 



Nineteen, or 38 per cent., were recaptured, namely, 12 males (48 per cent.) and 

 7 females (28 per cent.). Eight of the males were of mature size on recapture, 

 averging 40 '2 cm., as against 38*7 cm., on hberation ; they were at hberty for 

 from 83 to 1185 days, the mean being 321 days ; they migrated distances of from 

 7| to 46 miles, the average being 24*2 miles, and the mean rate '6 mile. Four 

 of the males were of immature size, averaging 28*8 cm., and migrating a mean 

 distance of 5 miles. Two of the females were of adult size, and 5 under, on recap- 

 ture, the latter traveling from 2| to 4 miles, the average being 3'2 miles. 



The Extent and Direction of Migration. 



None of the fish was recaptured in the first, third, or fourth quarters, but 14 

 were taken in February, March, and April, the second quarter. 



Eight males and 1 female were taken in February, the female 3 miles to the 

 south and east, off Nairn, 2 of the males 2 miles to the south and west, off Fort 

 George ; a third, 13 miles to thesouth and east, in Burghead Bay; a fourth ,8 miles W. 

 by S. of Burghead, at a distance of 7| miles ; 2 were got off Brora, Dornoch Firth, 

 at 22 and 23 miles distant ; the seventh, south-east of Clyth Ness, at 46 miles to the 

 north and east ; and the eighth, at an unspecified locality in the Moray Firth. One 

 male and 3 females were taken in March, the male off Nairn, at a distance of 3 

 miles ; 2 of the females off Nairn, at 2^ and 4 m.iles ; and the third at Fort George, 

 2| miles to the north and west. In April, a female was recovered off Nairn, 4 miles 

 to the north and west. 



