19 



particulars exist, 6 moved to the iiortli and east, 10 to the south and east, 59 to the 

 north and west, and 121 to the south and west ; the mean direction taken to the 

 north and west in the different experiments ranged from N. 18° W. to N. 66° W., 

 and the mean direction of those which migrated to the south and west was from 

 S. 41° W. to S. 84° W. When drawn on a chart, these Unes run as follows : — 

 S. 63° W. passes into the Moray Firth, in a Une with Tarbet Ness ; S. 40° W. passes to 

 Troup Head on the south coast of the Moray Firth, so tliat the mean direction, in 

 this quadrant, of the expeiiments as a whole lies between Tarbet Ness and Troup 

 Head, that is, on the south shore of the Moray Firth. In the north-and-west 

 quadrant, the hne N. 18° W. passes close to Foula, off the south-west coast of the 

 Shetland Isles, and the hne N. 66° W. passes close to the north of the Orkneys. 



An interesting feature of the experiments at Fair Isle is the number of plaice 

 which moved south, not only into the Moray Firth and its southern part, but 

 travelled on, south of Rattray Head, to the east coast of Scotland. For instance, 

 26 were found to the south of Buchanness, a few of them near the Bell Rock or off 

 the mouth of the Firth of Forth, others off the coast of Aberdeen. Thus, these fish 

 migrated in a direction contrary to that of the majority which were marked on the 

 east coast, that is to say. in the direction of the current instead of against it. It 

 would appear that these fish, in moving from the deeper to the shallower water, 

 continued their movement n the direction in which they began it. It is question- 

 able whether the movement of the current in the depths at Fair Isle is anything hke 

 as strong as in the shallower water, and it is probable that it is this movement 

 which is the important factor in directing the migration of the fish. Of the total 

 number recaptured, 49 were taken to the west of the Orkneys, mostly on the north 

 coast of Scotland, but 17 of them west and south-west of Cape Wrath. 



3. The Spawning Migration. 



Special attention has been given to the migratory movements of hsh which 

 were found to be " spawning " or " ripe," when captured, and charts have been 

 prepared showing the migration of each " ripe " and " spawning " fish. The 

 number of marked plaice recaptured, which were described as "spawning," was 

 216, viz. 146 males, 67 .females, and 3 whose sex was not stated. 



I. Fish described as " Spawning." 



(1) FIRTH OF FORTH. 



From the experiments made at 20 miles east of the Isle of May, 21 of the plaice 

 recaptured were " spawning," 14 males and 7 females. One of these fish was found 

 in London, and the place where it was captured is unknown. Of the other 20, 

 18 were recovered to the north and east, at distances of from 16 to 238 miles, a male 

 being taken 16 m'les to the east of the Bell Rock ; 11, 8 males and 3 females, were 

 recaptured at Aberdeen Bank, or in its vicinity, at distances of from 37 to 55 miles ; 

 3 were recaptured in the Moray Firth, 2 in the neighbourhood of Banff, and 1 off 

 Dunrobin Castle ; 2 were got to the east of the Orkneys, at distances of 164 and 

 173 miles ; and 1 was recaptured 14 mJles W.S.W. of Cape Wiath, at a distance of 

 238 miles. The mean rates of movement of these fish ranged from 1*1 to 17 miles 

 per 10 days. One fish was recaptured 15 miles to the westward, near Carr Light, 

 and another S^ miles to the south-west of the station. 



The number of " spawning " plaice recaptured from the experiments in the Firth 

 of Forth between Elie and Fidra was 50, 30 males, 18 fonales, and 2 of unknowTi sex. 

 The place of capture of all but 1 of the females was ascertained. Of the total, 46 

 had migrated to the north-and-east, and 3 to the south-and-east. Of those which 

 were found to the north and east, 1 was taken within the hmits of the Firth of 

 Forth, I of a mile off Pittenweem, Fife, at a distance of 5 miles ; 2 north-east of 

 Fife Ness, at distances of 17 and 28 miles ; 3 east and south of the Bell Rock, at dis- 

 tances of 29 and 39 miles ; 2 north-east of May Isle ; 11 westward of Aberdeen Bank, 

 at distances of from 58 to 75 miles ; 1 off Aberdeen Bay, at 72 miles distant ; 4 off 

 Buchanness, at distances of from 81 to 90 miles ; 15 in the Moray Firth ; 12 on the 

 south shore of it, at distances of from 127 to 174 miles, most of them near Banff ; 



