122 



ward, 2 being taken off the coast of Aberdeenshire, 1 in the Moray Firth, 1 

 off the Moray Firth, and 1 at the eastern opening of the Pentland Firth. Four 

 were caught in the following winter and spring, and the fifth in the spring of 1914, — 

 that is to say, all during the spawning season. The condition of the testes was 

 ascertained in 3 cases, and they were " ripe " or " mature." These fish had 

 moved at a mean rate of from 2*2 to 5-5 miles per 10 days. 



Of the 7 females, 6 had migrated also to the north, distances of from 

 50 to 127 miles ; 4 of these were taken off the coast of Aberdeenshire, 1 in the 

 Moray Firth, and 1 off the Moray Firth ; 4 were caught in January, February, 

 and March 1913, in the next spawning season, and they were " nearly ripe," " ripe," 

 or " spent " ; 1, taken in July 1913, was " apparently spent," and the remaining 

 fish (which had gone 50 miles), taken in September, was " immature." The rate 

 of movement in these cases also was rapid, varying from a mean of 1*7 to 4*8 miles 

 per 10 days. The seventh female was the one which was recorded as caught on 

 22nd February 1914, off Terschelling Island, on the Dutch coast, a distance of 

 300 miles S. 43° E. ; it was " spent," and had moved at the rate of 4-5 miles per 

 10 days. 



It is evident that these long migrations were for spawning purposes. 



Maturity. 



The condition of the reproductive organs was ascertained in 55 of the fish, 

 as follows : — Two were " spawning," both males, and both recaptured to the north, 

 off the coast of Aberdeen, in March 1913, not far apart, viz. 48 and 49 miles respec- 

 tively from the station. (A third fish, a female, was captured in this region, 46 

 miles distant, in April, and was " immature.") Two fishes were " ripe," a female, 

 caught in March 1913, 74 miles to the north-east, and a male caught in April 1913, 

 92 miles north-east. All the fish actually " spawning " or " ripe " were thus 

 recaptured to the northward. Seven fishes were "nearly ripe"; 1, a female, 

 got in August 1912, 5 miles to the south-west, is described as in this condition ; 

 a male was taken 37 miles to the north-east in October 1912 ; a female, in January 

 1913, 70 miles to the north-east, and another female, also in January, 127 miles 

 to the north-east. Three were recaptured in the south-west, in addition to the one 

 mentioned above, a male, at a distance of 15 miles, in December 1912 ; a female, 

 also in December, at a distance of 5 miles, and another female, in January 1913, 

 at a distance of only 4 miles from the place of hberation. The condition of the 

 reproductive organs of 2 males, taken in January 1913, at 71 and 149 miles to the 

 northward, was unfortunately not ascertained. Four fishes are described as 

 "spent," all females; 1, caught in June 1912, 20 miles to the north-east; 

 another, taken in February 1913, in the Moray Firth, 115 miles distant ; a third, 

 in May 1912, 6 miles to the south-west ; the fourth, in June, 8| miles to the south- 

 west. 



Relation of Movement to Size. 



There does not appear to be any clear relation between the size of the males and 

 the distance migrated. The sizes on liberation and on recapture of the 5 males 

 above referred to were as follows : — 40-49-2 cm., 39-41-7 cm., 36-39-8 cm., 

 32-40-8 cm. ; 35-41 cm. Some of the large specimens had moved very small 

 distances. Thus, 1 of 39-5 cm. on liberation and 42-2'cm. on recapture, had moved 

 apparently only 8 miles to the north and west, though it had been at liberty for a 

 period of 722 days. Another, of 35 cm. on liberation and 49-7 cm. on recapture, 

 had moved only 8 miles also north and west, after 538 days of freedom. In the case 

 of the females, the majority of the larger specimens moved only short dis- 

 tances. The sizes of the 7 females above referred to were as follows: — 40- 

 46 cm., 35-39-3 cm., 37-41-3 cm., 35-45-6 cm., 37-5-42-5 cm., 39-5-44-9 cm., 

 41-44-9 cm. But other large females, which had, in many cases, been at liberty 

 for long periods, had apparently moved very small distances, as the following table 

 shows : — 



