261 



cm., and 1 only was uiidei adult size on liberation ; the size of the females was 

 from 32 to 59 cm., and 2 were mider adult size. Tiie number recaptured was 6, 

 or 23-1 per cent., 1 male and 5 females. The male was recaptured iii March 1912, 

 94 miles to the south and west. One of the females was taken in October 1912, 

 12 miles to the south and west, and another, also in Oc'tober, 37 miles to tlie south 

 aud east; the third was found in November 1911, 110 miles to the south and 

 west ; the fourth, in January 1912, 217 miles to the south and west, 159 miles 



E. I 8. of Spurn Head ; and the last, at a distance of 220 miles to the south and 

 east. 



On 17th June 1910, 17 plaice, captured in the vicinity, were marked and 

 hberated at the position 57° 20' N. ; 3° 39' E., viz. 6 males, Gfemales, and 5 whose 

 sexes were not ascertained. Only 2 were recaptured, a male in May 1911, 10 

 miles to the south and west, and 1 of unknown sex in August 1910, 11 miles to 

 the north and west. 



On the day following, 6 fish, 2 males aj\d 4 females, were hberated at 57° 1' N. ; 

 3° 52' E., and on the 20th, 4 plaice, 3 males and a female, at 56° 58' N. ; 4° 15' E., 

 but no fish from either of these 2 experiments was recaptured. 



On 21st June 1910, 12 plaice, caught in the locality, were marked and set free 

 at the position 56° 37' N. ; 3° 42' E., 5 males, 6 females, and 1 of unknown sex. 

 Three were recaptured, a male in July 1910, 45 miles to the north and west, 

 another male in Februarj^ 1911, 86 miles to the south and west, and a female in 

 October 1910, 34 miles to the south and east. 



On 13th June 1912, 98 maiked plaice were hberated at the position 57° 12' N. ; 

 4° E., viz. 38 males, 57 females, aud 3 whose sexes were not ascertained. The 

 fish used were taken by the " Goldseeker " on the 11th June, m Kirkcaldy Bay, 

 were marked on the 12th, and Ubeiated on the 13th ; 6 fish died in the ta,nks in 

 the ijiterval. The males ranged in size from 27 to 42 cm., and 23 were under 

 adult size ; the females ranged from 27'5 to 48'5 cm., and 43 were under adult 

 size. 



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

 follows : — 



cm. cm. cm. cm. cm. 



25-30-5 31-35-5 36-40-5 41-45-5 46-50-5 Total. 



F. Lib. ... 16 22 J 1 6 2 57 

 F. Recap. . . 2 6 1 1 _. 10 



M. Lib. ... 17 14 5 2 — 38 



M. Recap. . . 2 2 1 _ _ 5 



?Lib. ... — 1 2 — — 3 



? Recap. . . — — — — — — 



Only 15, or 15*8 per cent., were recaptured, 5 males (13*2 per cent.) and 10 

 females (18-5 per cent.). All the males were of adult size on recapture, ranging 

 froju 36-9 to 43-5 cm., and averaging 40-2 cm., as compared with a range of from 

 28-5 to 41 cm., and an average of 33-6 cm. on liberation ; they were at liberty 

 for the average period of 672 days, and migrated fiom 36 to 86 miles, the mean 

 being 50-5 miles, and the mean rate of movement "75 mile. Six of tne females 

 were of adult size, ranging from 38-6 to 48 cm., and averaging 43-2 cm., as com- 

 pared with a range of from 33*5 to 45-5 cm., and an average of 37*2 cm. on libera- 

 tion ; they were at fiberty for from 116 to 1293 days, the mean being 588 days ; 

 they migrated distances of from 62 to 179 miles, the average being 108-4 miles, 

 and the mean rate 1-8 miles Four were mider adult size, averaging 32-5 cm., 

 as compared with an average of 30-5 cm. on liberation ; they were at liberty for 

 the mean period of 268 days, and travelled distances of from 2 to 247 miles, the 

 mean being 77-5 miles, and the average rate of movement 2-9 miles. 



The Extent and Direction of Migration. 



The first fish to be caught were taken in October 1912, viz. 2 females, one 27 

 miles to the south and east, and the other 72 miles to the south and west. 



