SEA-FISHERIES LABORATORY. 931 
Each spot indicates the approximate place where a fish 
has been recaught, and only those records which appear 
to have been above suspicion of error have been included. 
The chart is interesting, for it gives a graphic repre- 
sentation of the distribution of plaice in this part of the 
sea, which cannot be deduced from any series of 
statistics, ‘‘commercial’’ or otherwise, hitherto pub- 
lished: parenthetically, one may remark that a far 
more probable picture of the distribution, density and 
migrations of any one species of edible fish, such as the 
plaice, is to be obtained from the results of such “‘ purely 
scientific ’’’ experiments as these, combined with the 
statistical examination of actual catches made by an 
exploring vessel under ordered conditions, than can be 
obtained from any system of statistical collection of 
data at the ports of landing. Obviously it is only such 
knowledge of the distribution, density and migrations 
of a species that can be of value for fishery administra- 
tion; a knowledge of the quantities of fish landed at 
the ports helps us very little. 
Tt will be seen from the chart that plaice are caught 
(in the eastern half of the Irish Sea) almost entirely 
within the 20-fathom lne. In addition to the fishery 
which is carried on at most parts of the coast, but 
particularly in the bays and estuaries, by stake nets and 
second class sailing boats, there is an off-shore fishery 
which is concentrated to some extent on three roughly 
defined areas :— 
(1) In the part of the sea South from parallel 54° N., 
and North-East from a line joining the estuary of the 
Dee and the South end of the Isle of Man. Plaice are 
trawled for over most of the sea-bottom inside this area, 
and between the land and the 20-fathom line. There is 
a curious vacant area opposite Blackpool and at the 
