REPOPULATION 131 



miles. Of 71 rays, 2 were retaken ; of 4 turbots and 273 

 soles only one of each species. If we establish the ratio 

 of marked fish to fish recaptured, we obtain the following 

 series : turbot, plaice, cod, common dab, ray, sole ; a series 

 in which the species are arranged according to the extent 

 of their travels. In other words, the turbot and plaice 

 are more sedentary than the sole. Between 1901 and 

 1903 a large number of plaice were marked and released 

 in English and Scottish waters. At the end of 60 days 

 more than 10 per cent, were retaken, at an average 

 distance of 150 miles from the point of release. As a 

 rule plaice do not leave the North Sea. There is a 

 record of one, however, which was released on the Lemon 

 Bank near Cromer in December, 1903, to be retaken in 

 April, 1904, at a distance of 200 miles in the open 

 Channel, off Winchelsea. Later experiments have re- 

 sulted in the recapture of as much as and more than 

 20 per 100 of the marked specimens. It is doubtless 

 too soon to draw definite conclusions from experiments 

 of this sort, which are difficult and costly ; however, 

 they bring before us three important truths : (i) The 

 species that live upon the sea-bottom do not remain 

 absolutely in one place, as though glued to the sand. 

 (2) Their movements are neither very rapid nor very 

 extensive. (3) On the whole, they remain within a 

 comparatively restricted area. 



These are not empty scientific experiments. Not only 

 do they give us information as to the habits of fish ; 

 they render possible a valuable kind of industrial 

 operation. If the marked fish, young or adult, are 

 rejected not at the place of their capture, but elsewhere, in 

 a propitious locality suitably chosen if, in a word, they 

 are "transplanted" we can "plant" such a fishing- 

 ground as we please, just as a field is sown. 



