980 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Experience of the investigations made in the Irish 
Sea during the last half-dozen years seems to show that 
the general methods involved in fish-marking experi- 
ments are sound enough. ‘The only practicable 
improvement in method suggested by the _ results 
summarised in this report is the adoption of a few—four 
to six—large experiments in the year, instead of, say, 
twelve to twenty small ones. Further, the study of 
some preliminary experiments in any area of sea will 
indicate what should be the seasons for the experiments, 
and the places of liberation: obviously these will depend 
on the natural distribution of plaice in the area, and the 
incidence of the fishery seasons. It is now obvious 
enough when and where plaice should be marked and 
liberated so far as the Irish Sea on the eastern side is 
concerned. 
2. STATIONS. 
When the experiments were begun in 1904, they 
had to be made in such a way so as not to interfere with 
the other (and primary) duties of the steamer employed. 
Therefore a number of small experiments were made at 
convenient times. But it is clear, on considering the 
results, that not much is to be learned from the results 
of marking 30 to 50 plaice. Latterly large experiments 
were made, the opportunities for investigation of this 
nature having become more frequent. Meanwhile I 
propose to group together a number of the smaller 
experiments, considering each group as a unit. In 
making these groupings one is guided by a knowledge of 
the natural conditions of the fisheries on the eastern 
side of the Irish Sea. 
The sketch-chart on p. 257 shows the general 
distribution of the marked fish recaught and returned. 
