126 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
December are sexually mature fish, but they do not spawn 
there. The spawning grounds of these plaice are further 
to the south in St. George’s Channel. 
(8) The question of Legal Size-limits. 
Data for the discussion of the effect of these on the local 
fisheries have already been referred to in the previous article 
in this Report. But these marked fish experiments give us 
some notion of the extent to which the “deep sea” plaice 
fisheries may be expected to benefit by a restriction of the 
size of capture of plaice in in-shore waters. 
Little over 3 per cent. of the 1,160 plaice marked on the 
Lancashire nursery grounds have been observed to migrate 
permanently mto the deep water off-shore. Less than 1 per 
cent. of these marked plaice have been recovered from outside 
the eastern part of the Imish Sea. These data do not give 
much assurance that the result of protecting the small plaice 
in-shore will lead to a notable increase in the numbers of large 
plaice off-shore. The data are very few, but I know of no 
others relevant to the legislative question involved. 
It is well known that large plaice were at one time much 
more abundant on the banks off the North-east Coast of 
Isle of Man than they are nowadays. These banks are 
undoubtedly fed by small plaice from the shallow water 
nurseries. The reduction of the stock of large plaice on them 
is to be traced to intense fishing, mainly by steam-trawlers, 
during modern times. It cannot be denied that this stock 
of large plaice might be increased by favouring the off-shore 
migration by restricting the capture of small plaice in-shore— 
to an unknown but certainly small extent. Such restrictive 
legislation would, in all probability, greatly reduce the catch 
of small plaice in-shore, and slightly increase the catch of 
medium and large plaice off-shore, and the economic question 
to be considered is this :—Is wt worth while? 
