254 

 The numbers liberated and recaptured, arranged in5-cra. groups, are as follows 



The number recaptured was 116, or 40-4 per cent., viz. 46 males (43-4 per cent.), 

 69 females (44-2 per cent.), and 1 whose sex was not ascertained. The place of 

 capture of 6 of the fish was not ascertained, or was uncertain. One was found at 

 Billingsgate, 1 on the pontoon, Grimsby, 1 at Altona, 1 at Ymuiden, and 1 at London. 

 So far as the port of landing is recorded, 41 of the fish were landed at liondon, 

 31 at Hull, 14 at Hamburg, 7 at Altona, 7 at Grimsby, 6 at Aberdeen, and 1 each 

 at Ymuiden, Cuxhaven, and Bremerhaven. 



Of the remaining fish, 44 were of adult size on recapture, averaging 37-8 cm., 

 and ranging from 33 to 45-6 cm., as compared with a mean of 35-8 cm., and a 

 range of from 31-5 to 41 cm., on liberation ; they were at liberty for from 10 to 

 1314 days, the mean being 266 days ; they moved distances ol from H to 220 

 miles, the average being 38-1 miles, and the mean rate of travel 1-4 miles. Two 

 of the recaptured males were under adult size ; they were free for a mean period 

 of 17 days, and moved 18 miles and 25 miles respectivelj . Of the females, 32 

 were of adult size on recovery, averaging 41-4 cm., and ranging from 38 to 48-4 cm,, 

 as against a range of from 32 to 41-5 cm., and a mean of 36-7 cm. on Uberation ; 

 they ^\ ere at liberty for from 6 to 1044 days, the average being 415 days ; they 

 migrated distances of from 1| to 232 miles, the average being 45*1 miles, and the 

 mean rate Tl miles. Thirty-sever were under adult size, ranging from 30-5 to 

 37*7 cm., and averaging 354 cm., as compared with a range of from 32-5 to 40 cm., 

 and an average of 35"3 cm., on liberation ; they were free for from 4 to 495 days, 

 the mean being 114 days ; they migrated from U to 148 miles, the average being 

 35*7 miles, and the mean rate of movement was 3-3 miles. 



The Extent and Direction of Migration, 



First Quarter. — In the remainder of June, 5 males and 11 females were taken. 

 With one exception, they were found at short distances from the station, and the 

 exception is more than doubtful. Three of the males and 3 of the females had 

 moved to the south and west for from 1-|- to 15 miles ; 2 of the males were found 

 to the south and east, 1 at 6 miles, and the other, along with 1 of the females, at 

 21 miles ; 5 of the females went to the north and east, 4 being caught on the same 

 day, and probably by the same vessel, as they were all landed at London, at a 

 distance of 5 miles, and 1 at a distance of 10 niiles. One female, landed at Cux- 

 haven, is represented as having been recaptured after 4 days, at a distance of 112 

 miles to the westwards, which is obviously a inistake. 



Eleven males and 12 females were recaptured in July, but the place of capture 

 of 1 of the males is not recorded. Nine of the other males and 6 of the females 

 were taken to the south and east, the males at distances of from 14 to 25 miles, 

 and the females at distances of from 11 to 23 miles. One male and 1 female were 

 found to the north and west, at distances of 12 and 27 miles. Four females were 

 taken to the south and west, 3 at distances of from 8 to 15 miles, and 1, after 24 

 days, at 113 miles distant, representing a mean rate of travel of 4*7 miles per day ; 

 it is probably erroneous. 



One male and 4 females were recaptured in August, the male and 1 female 

 to the south and east, at distances of 35 and 31 miles ; the other 3 females to the 



