297 



a distance of 124 miles. Four were " ripe," 3 recaptured in February 1912, all 

 at the mouth of the Dornoch Firth, at distances of 11, 11, and 15| miles, and 1 

 in March 1912, in the same locality, at a distance of 15| miles. Two were described 

 as " spent," 1 found in March 1912, and 1 in February 1914, the former at the 

 entrance to the Dornoch Firth, at a distance of IH miles, and the other 13 miles to 

 the north and east. Two were " nearly ripe," 1 taken in February 1912, 26 miles 

 to the south and east, and the other in December 1912, 36 miles to the north and 

 east. 



Females. — The condition of the ovaries of 21 of the 33 females was recorded. 

 One was " spawning " ; it was caught in February 1913, off Clyth Ness, 17 miles to 

 the north and east, and it measured only 37*7 cm., and would have been classified 

 as under the adult size. Two were " ripe," both caught in March 1912, 1, 11 miles 

 to the north and west, and the other on the north coast, off Strathie Point, 80 miles 

 distant. Three were "spent," all got in April 1912, 1 off Noss Head, 37 miles to 

 the northwards, another off the north coast, at Stormy Bank, at a distance of 

 74 miles, and the third near Cape Wrath, on the west coast, at a distance of 122 

 miles. 



Experiment near Burghead, Moray Firth. 



^2th December \%\^. 



On 12th December 1913, 100 plaice were marked and liberated off Burghead, 

 on the south coast of the Moray Firth, at a position 2^ miles N.W. by W. \ W. 

 (Lat. 57° 42' N. ; Long. 3° 34' W.) in a depth of 6 fathoms. The males ranged in 

 fize from 38 to 46-5 cm., and all were thus of adult size. The females varied from 

 39 to 56 cm., all being of adult size. 



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

 follows : — 



The fish used were taken in Burghead Bay by the " Goldseeker." 

 The number recaptured was 53, or 53 per cent., viz. 28 males (58-3 per cent.) 

 and 25 females (48-1 per cent.). The sizes of the males ranged from 38-5 to 47 cm., 

 and averaged 42-6 cm., as compared with a range of from 38 to 46*5 cm., and a 

 mean of 42-5 cm. on liberation ; they were at hberty for from 13 to 441 days, the 

 average being 123 days; they travelled distances of from 2i to 187 miles, the 

 mean being 29-3 miles, and the average rate was 2-3 miles. The females ranged in 

 size from 38-5 to 53-5 cm., and the average was 46-5 cm., as against a variation of 

 from 39 to 50 cm., and an average of 44-3 cm. on hberation ; they were free for 

 from 12 to 965 days, the mean being 283 days : they migrated from 2 to 139 miles, 

 the average being 31*2 miles, and the mean rate was LI miles. 



The Extent and Direction of Migration. 



FirH Quarter. — A male and 2 females were recaptured m the remainder of 

 December, all 12 miles to the northwards, to the mouth of the Dornoch Firth. 



Li January 1914, 3 males were captured, but the position of 1, which was landed 

 at Grimsby, was given merely as " Moray Firth " ; the other 2 were found to the 

 northwards, 1 off Tarbet Ness, near the entrance to the Dornoch Firth, at 11 miles 

 distant, and the other at a distance of 40 miles, off Clyth Ness, near the edge of 

 Smith Bank. Ten males and 5 females were got in February ; 5 of the males and a 

 female were taken near Tarbet Ness, towards the Dornoch Firth, 4 at a distance 

 of 11 miles, 1 at 13| miles, and another at 14 miles ; a male and a female were 

 recaptured south-east of Berriedale Head, at 23 and 24 miles to the northwards ; 

 a male a little farther to the north, south of Lybster, 30 miles distant, a female 



