SEA-FISHERI“S LABORATORY. 129 
bye-laws introduced at the beginning of the present year. 
Formerly a trawl-net of 6-inch mesh was only allowed in 
certain places and at certain periods of the year, but since 
January, 1908, this form of trawl-net has become legal 
over all parts of the Lancashire and Western Sea Fisheries 
District. It is possible that the increase in catching 
power thus legalised may affect the density of plaice in 
local waters, but it 1s practically certain that the statistics 
of the fishery, as at present collected, could not be used 
so as to exhibit any such changes. It is indeed possible 
that the increase in catching power, brought about by 
allowing a 6-inch trawl mesh to be used everywhere, 
instead of only allowing it during a part of the year, and 
in a restricted area, may not be significant, for the natural 
productivity of the Irish Sea’ fishing grounds may easily 
bear this extra demand. But however this may be, it is 
probable that it 1s only by a study of the modal sizes of 
the plaice caught for the next two or three years, that 
any change in this productivity is to be detected. If 
there should be no such change, then we may be fairly 
sure that the relaxation of the restrictions on trawling 
and trawl-net meshes is not lkely to be detrimental to 
the fishing grounds. 
It would, of course, be premature to discuss these 
data at the present time, and they are collected and 
summarised here in order to save the time that would be 
spent in working them up if they were allowed to 
accumulate. It is also necessary to study the figures 
collected from time to time in order that any changes in 
methods suggested might be adopted. 
