h32. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
THE PLAICE FISHERY OF 1892-1917. 
By JAMES JOHNSTONE, D.Sc. 
Some interesting results have been obtamed during the 
examination and tabulation of the statistics of experimental 
trawling operations carried out during the past 25 years. 
A report on these results has been prepared, and it is hoped 
that it may be possible to publish this at some future time. 
Meanwhile, allusion may be made to some points of special 
interest. 
The Plaice Fishery of the Mersey Estuary. 
Experimental hauls with fish-trawl nets of various meshes 
and dimensions, and also with shrimp-trawl nets, have been 
made regularly since 1892 by Captain Eccles. These trawling 
operations were carried on in the Mersey Channels and outside 
the Banks. As a rule, they have been made under nearly 
uniform conditions, and all the circumstances as to weather, etc., 
are recorded. Since about 1908 all the plaice caught have 
been individually measured in centimetres—work requiring 
considerable patience and accuracy. 
In considering these figures, one sorts them out ito 
average catches of plaice, etc., per haul per month—or into 
average catches per hour’s fishing per month or per annum. 
The latter is the most obvious way of dealmg with the figures, 
and we see at once that there are quite remarkable’ variations. 
Nevertheless, to take the numbers of plaice caught per hour’s 
fishing, per month, is not a very satisfactory method, for there 
are usually not very many hauls per month, nor even per year. © 
And in comparing year with year there is the difficulty that 
some months are well represented in some years but not in 
