246 TRANSACTIONS LIVERPOOL. BIOLOGICAL SOCIETY. 
of the plaice taken in the Red Wharf Bay area is 
significantly greater than that characterising the fish of 
the other two areas, and that since the migrations in 
question are spawning ones, it is likely that the larger 
fish would participate in it to a greater extent than the 
others. 
7. Intensity of Fishing. 
One may be expected to discuss the question of 
whether or not the relative intensity of fishing can be 
deduced from the relative proportion of recaptures in 
different areas, during the same period of time. Now 
no one with experience of fishery investigation is lkely 
to claim that the amount of fishing is exactly in pro- 
portion to the percentages of marked fish recaught; 
but, given that the same care is always observed in 
catching, sorting and marking the fish, and that the 
same investigators have carried out the experiments 
compared, then it seems to me that some degree of 
correlation must exist between the relative intensity 
of fishing and the relative percentages of recaptures 
given good fishery statistics and it should be possible 
to express this correlation numerically. If, again, 
anyone with experience of the local fisheries examines 
such a chart as I, p. 257, he will notice that it is just 
where the trawling and stake-netting are most exten- 
sively carried on that there are most recaptures. If 
his attention were drawn to the paucity of recaptures 
in certain regions, he will probably say that this is 
because little trawling is carried on there. And this 
is equivalent to asserting that there is correspondence 
between intensity of fishing and percentage of recaptures, 
