151 



One was " three-quarters ripe" ; it measured 41-43-2 cm., and was recovered in 

 August 1912, after 351 days, 50 miles N.N.E. of Buchanness, a journey of 117 jniles. 



Three were said to be "fully half-ripe," 2 being recaptured in October 1911, 1, 

 measuring 37-5-38-3 cm., 30 miles to the north-west, and the other, of 40-41-2 cm., 

 42 miles to the north and east ; the position of the third was not recorded. One, 

 of 42-5—44-3 cm., was described as " about half-ripe " ; it was recaptured in August 

 1912, far offshore, to the north-east of Buchanness, at a distance of 112 miles. A 

 female, of 41-44-6 cm., taken in June 1912, offshore, at a distance of 47 miles to 

 the north and east, was said to be " a quarter ripe." 



All the other females of adult size were " immature." Three were caught in 

 the month of April ; 1, of 41-42-5 cm., after 231 days, 15 miles to the north and 

 west ; another, of 39-5-41 cm., after 227 days, oM Buchanness, at a distance of 65 

 miles to the north and east ; the third, after 229 days, 32 miles to the north and 

 west. 



A female, which measured only 34-36-2 cm., and was caught in February 1912, 

 after 156 days, 24 miles to the south and west, was described as " half -ripe." 



EXPERIMENT III. 



12th June 1912. 



The number of plaice marked and Uberated in this experiment was 90, comprising 

 27 males, 60 females, and 3 whose sexes were not determined. The sizes of the males 

 ranged from 29-5-41 cm., and 12 were under the adult size (33 cm.) ; the sizes of the 

 females ranged from 24-5-48 cm., and 40 were under the adult size (38 cm.). The 

 numbers hberated and recaptured are shown in the following table, arranged in 

 groups of 5 cm. : — 



cm. cm. cm. cm. cm. 



25-30-5 31-85-5 36-40-5 41-45-5 4fi-50-5 Total 



F. Lib. ... 10* 24 16 8 2 60 



F. Recap. ... 7 17 7 5 — 36 



M. Lib. ... 5 18 3 i _ 27 



M. Recap ... 2 11 3 — — 16 



?Lib. ... — 1 1 _ _ 3| 



? Recap. ... — 1 — — — 2t 



* One at 24-5 cm. f Two no sizes given. 



The plaice used in this experiment were trawled by the " Goldseeker " in Kirk- 

 caldy Bay, Firth of Forth, on the 11th June 1912, and were marked and put in 

 tanks between 2.50 and 3.55 p.m. ; they were Uberated at 1.20 p.m. on the follow- 

 ing day. Eighteen of the marked fish, on this occasion, died while in the tanks. 



The number recaptured was 54, or 60 per cent., viz. 16 males (59-3 per cent.), 

 36 females (60 per cent.), and 2 whose sexes were unknowii. 



Thirteen of the males were of adult size, measuring, on recapture, from 34-6- 

 41-9 cm., with an average of 38-3 cm., compared with 29-5-37-5 cm., and a mean of 

 33-5 cm. on Uberation ; the fish were at Uberty for from 17 to 1377 days, the mean 

 being 453 days ; the distances migrated varied from 9 to 194 miles, with, an average 

 of 58-2 miles, and a mean rate of movement, per 10 days, of 1-3 miles. 



Three males were immature, the average size being 32-4 cm., as compared with. 

 32 cm. on Uberation ; they were free for an average period of 132 days, the average 

 distance travelled being 20-6 miles, and the mean rate of movement 1-56 miles per 

 10 days. 



Twelve of the females were of adult size on recapture, averaging 43 cm., and 

 ranging from 38-5-49-3 cm., as compared with an average size of 38-9 cm., and a 

 range of 33-5-44-5 cm. on Uberation ; they were at Uberty for from 26 to 1001 da3'S, 

 the mean being 466 days ; they moved journeys of from 3| to 120 miles, the average 

 being 45 miles, and the mean rate of migration, per 10 days, -97 mile. 



Twenty-four of the females were under adult size, ranging from 29-4-37-5 cm., 

 the mean being 33-9 cm., as compared with a variation of from 28 to 38 cm., and a 

 mean of 32-5 cm. on Uberation ; they were free for from 15 to 400 days, the average 

 being 142-6 days ; the distances moved ranged from 3i to 59 miles, the mean being 

 27-7 miles, and the mean rate 1-99 miles per 10 days. 



