128 



The numbers liberated and recaptured are shown, in groups of 5 cm., in the 

 following table : — 



F. Lib. 

 F. Recap 



M. Lib. 



M. Recap. . 



?Lib. . . — — 2 — — — 2 



The fish which were marked in this experiment were caught at Station VI., 

 Firth of Forth (oif St. Monans), at 4 p.m. on the 6th December, and were Hberated 

 the same evening about 8 o'clock, all in good condition. 



The number recaptured was 132, or 65-3 per cent, of those liberated, comprising 

 55 males (70-5 per cent.) and 77 females (63-1 per cent.). The date of recapture 

 of one was not ascertained. 



Of the males caught, all but 4 were over 33 cm. in length, and may accordingly 

 be considered adult. These, 51 in number, had been free for periods ranging from 

 12 to 670 days, the average being 283 days ; their sizes on liberation ranged from 

 27-5 to 43 cm., the mean being 35-5 cm., and on recapture they ranged from 33-4 to 

 446 cm., with an average of 37-5 cm. The positions of recapture were ascertained 

 for 48 of them ; the distances travelled varied from 1-5 to 239*5 miles, the mean 

 being 43-7 miles, and the average rate of travel per 10 days 1-9 miles. Of the 

 4 immature males, the average period of freedom was 85 days, the average size on 

 liberation 31-6 cm., and on recapture 31-3 cm. ; they had migrated distances of 

 from 26 to 138 miles, the mean being 84 miles, and the average rate of movement 

 9-8 miles. 



Of the females, 49 were of adult size, and the positions of recapture of all except 

 1 were ascertained. The sizes on liberation varied from 31-5 to 54-5 cm., the average 

 being 40-1, and on recapture from 38-5 to 55-4 cm., with an average of 43*7 cm. ; 

 they were at liberty for periods varying from 3 to 965 days, the mean being 344 

 days, and the distances travelled ranged from 3 to 176 miles, the mean being 

 56-1 miles, and the average rate of travel per 10 days 1-7 miles. Of the 28 females 

 of immature size, the positions of recapture were ascertained for 26. They were 

 free for from 3 to 383 days, the mean being 150 days ; they moved from 2 to 191 

 miles, the average distance being 44| miles, and the mean rate of migration per 10 days 

 was 2-8 miles ; on liberation, their sizes varied from 27-5 to 37 cm., averaging 

 33*4 cm., and on recapture from 28 to 37-8 cm., the mean being 35-1 cm. 



The Extent and Direction op Migration. 



First Quarter. — Of the 202 fishes set free, 7 were recaptured in the same month, 

 6 females and 1 male, and the position of recapture was determined in each case, 

 except in that of one of the females. Four of the fishes, including the male, had 

 migrated for a distance of 5 mi'es, 3 to the south-east, and 1 to the south-west ; 

 the other 2 had moved north-east, 1 for a distance of 21 miles in 3 days, and the 

 other for 62 miles, being taken, after 20 days, off the coast of Aberdeen. This 

 fish measured only 34-3 cm. on recapture, and was " immature." 



Seven were taken in January 1913, the next month after liberation, 5 males 

 and 2 females. One, a male, was got 17 miles to the north-west, after 42 days ; 

 another, a female, was found 3 miles to the south-east ; and 4, 1 female and 

 3 males, to the north-east, off the coast of Aberdeen, at distances ranging from 

 42 to 73 miles ; the position of recapture of the remaining male was not ascertained. 



In February, 17 plaice were recaptured, 8 females, and 9 males, the 

 position of capture being ascertained in all cases. One female moved 12 miles 

 to the south-west, 5 migrated north-west distances of from 17 to 32 miles, 10 

 moved to the north and east, distances ranging from 44 to 239 miles. Most of these 

 were taken off the coast of Aberdeen; 3 were found in the Moray Firth, and 

 1, a male which measured 35 to 35-2 cm., was taken off Cape Wrath, at a distance 

 of 239-5 miles, on the 28th February, after 84 days, the rate of travel in this case 



