83 



EXPERIMENT II. 



•SOth May 1913. 



In the secoud experiment at this station, wliich was made on 3Uth May 1913, 

 100 fish were Hberated, consisting of 40 males, 59 females and 1 whose sex was not 

 ascertained. The males ranged in size from 27"5-41 cm., and 28 were under adult 

 size. The females varied from 28'5 to 56-6 cm., and 43 were under adult size on 

 liberation. 



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

 follows : — 



cm. cm. i-m. cm. cm. cm. cm. 



•25-30-5 31-35-5 3l)-40-5 41-455 4G-.50-5 51-55-5 5()-(i0-5 'J'otal. 

 F. Lib. . 9 28 10 7 2 1 2 59 



F. Recap. . 4 15 4 4 1 — — 28 



M. Lib. . 12 26 1 1 — — — 40 



M. Recap. .6 16 1 _ _ _ _ 23 



? Lib. . . — 1 _ _ _ _ _ 1 



? Recap. . — 1 — — — — — 1 



The fish used in this experiment were trawled by the " Goldseeker " on the 

 same day at the " Garland " Station II., in the Firth of Forth, i.e. in the North Bay, 

 off West Wemyss. 



The number recaptured was 52 (52 per cent.), comprising 23 males (57-5 per 

 cent.), 28 females (47-5 per cent.), and the fish of unknown sex. All the males 

 recaptured were of adult size, ranging from 34 to 43"5 cm., and averaging 37'3 cm., 

 as compared with a range of from 27-5 to 36-5 cm. and a mean of 32*1 cm. on libera- 

 tion ; they were at liberty for from 99 to 981 days, the mean being 393 days ; they 

 migrated distances of from 6 to 204 miles, the average being 54 miles, and the 

 mean rate of movement, T4 miles. Twenty of the females were of adult size, 

 averaging 41-6 cm., and varying from 38-4 to 50-3 cm., as against a range of from 

 31-5 to 48"5 cm., and an average of 36-5 cm. on liberation ; they were at Uberty for 

 from 161 to 815 days, the average being 359 days ; they travelled from 6 to 145 

 miles, the mean being 57-3 miles, and the average rate of movement 1-6 miles per 

 10 days. Eight of the females were under the adult size, averaging 36-5 cm., as 

 compared with 31-2 cm. on Uberation ; they were free for a mean period of 390 

 days, and moved from 7 to 88 miles, the average being 35-5 miles, and the mean 

 rate, '9 mile per 10 days. 



The Extent and Direction of Migration. 



First Quarter. — None of the marked fish was recaptured in the fiist 3 months 

 following Uberation. 



Second Quarter. — A male was taken in September, after 99 days, off Wemyss 

 Castle, in the Firth of Forth, at a distance of 10 miles to the north and west. 



In November, a male and a female were captured, both to the north and east, at 

 distances of 16 and 22 miles respectively. Only 3 fish were thus recovered in the 

 second quarter. 



Third Quarter. — Two males and 1 of unknown sex were recaptured in December 

 1913, the 2 males to the north and east, at distances of 22 and 26 miles, near the 

 Bell Rock. The fish of unknown sex was captured 167 miles to the south and east, 

 28 miles N.E. by N. of Spurn Head ; the mean rate of movement in this case was 

 8 miles per 10 days. 



In January 1914, 1 male and 2 females were got, all to the north and east, the 

 2 females to the south-east of Aberdeen, offshore, at distances of 67 and 73 miles 

 respectively, while the male was recaptured in the Moray Firth, off Banff, at 145 

 miles distant. 



Three males and 3 females were taken in February 1914, one of the males in the 

 Firth of Forth, 10 miles to the west and south ; a female was also taken in the 



