247 



The fish used in this experimert were trawled by the " Goldseeker," in Kirk- 

 caldy Bay, on the afternoon of the 11th June, and were marked between 3.35 

 and 6.25 p.m. They were kept in tanks of running water until midnight on the 

 following day, when they were hberated. Nine had succumbed in the- tanks. 



The number recaptured was 29, or 32 per cent., namely 14 males (35-9 per cent.) 

 and 15 females (31-9 per cent.). 



Of the males taken, 11 were of adult size, the average being 38"2 cm., and the 

 range from 35 to 42*1 cm., as compared with a mean of 34-2 cm., and a range of 

 from 28 to 38 cm. on liberation ; they were free for from 121 to 795 days, the 

 mean being 497 days ; they migrated distances of from 21 to 100 miles, the 

 average being 59'4 miles, and the mean rate, per 10 days, 1-2 miles. Three of 

 the males were under the adult size, the average being 30 cm., as compared with 

 29*3 cm., on liberation ; they were free for a mean period of 107 days, and 

 migrated an average distance of 60*6 miles, the mean rate of travel, per 10 days, 

 being 5*65 miles. 



Seven of the females were of adult size on recovery, ranging from 39 to 53 '3 

 cm., with an average of 43-9 cm., as compared with a mean of 41-6 cm. on hbera- 

 tion ; they were free for from 22 to 912 days, the mean being 386 days ; they 

 travelled distances of from 4 to 119 miles, the average being 74 miles, and the 

 mean rate of travel, per 10 days, was 1 -9 miles. Eight were under the adult size, 

 the average being 33-4 cm., as compared with 33-6 cm. on liberation ; they were 

 at liberty for a mean period of 217 days, and migrated distances of from 42^ 

 to 132 miles, the average being 70-5 miles, and the mean rate of movement 3-2 

 miles. 



The Extent and Direction op Migration. 



First Quarter. — None was caught in June, but 2 females were recaptured in 

 July, 1, after 22 days, a few miles off Tod Head, at a distance of 80 miles to 

 the westwards, having travelled at the mean rate of 364 miles per 10 days ; it 

 measured 54-53*3 cm., and was " spent " ; the other was taken to the east of 

 the Isle of May, 75 miles to the westwards, after 40 days, or at the mean rate of 

 18"9 miles per 10 days ; it measured 29'5-27'9 cm., and was " immature." 



Two females were recaptured in August, 1 off Longstone Light, after 70 days, 

 at a distance of 76 miles to the south and west, the average rate of migration being 

 10*8 miles per 10 days ; it measured 39-39 cm. ; the other female was got to the 

 east of May Isle, at a distance of 52 miles, after 78 days, the rate of travel being 

 6*6 miles per 10 days ; it measured 34'5-35 cm. 



Four fish, therefore, or 13*8 per cent., were taken in the first quarter, 3 of them 

 being to the west and south. 



Second Quarter. — Two males and 3 females were recaptured in September, 1 of 

 the males, after 87 days, 72 miles to the westward, off the Isle of May, the other, after 

 107 days, 41 miles to the north and west, to the south-east of Aberdeen ; 1 of the 

 females was taken south-east of Longstone Light, after 96 days, at a distance of 82 

 miles to the south and west ; another was recaptured, after 102 days, north-east 

 of the Bell Rock, at a distance of 42 miles to the north-west ; the remaining female, 

 which measured 31-30 cm., was got offshore, at a distance of 117 miles E. by S. i S 

 of Longstone Light (Lat. 55° 40' N. ; Long. 1° 55' E.). 



In October, 2 males were recovered, 1 south-east of May Isle, at a distance of 

 50 miles to the south and west, the other, 69 miles to the north and west, at a point 

 east of the Bell Rock. 



A male was taken in November, far offshore, to the north-east of Buchanness, at 

 a distance of 100 miles to the north and east, in 62 fathoms. 



Thus, in the second quarter, 8 fishes, or 27-6 per cent., were recaptured, 3 to the 

 north and west, and two to the south and west. 



Third Quarter. — Only 1 was taken in this period, namely, a female in February 

 1913, 60 miles to the north and west, at Aberdeen Bank ; it measured 37-37*6 cm., 

 and was " immature." 



Fourth Quarter.- — Two males and a female were got in May 1913 ; the female 

 was taken in the Firth of Forth, about 3 miles S.S.W. of Buckhaven, at a distance 

 of 117 miles to the westwards ; it measured 36-5-39"2 cm., and was " immature." 



