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It has been suggested that much the same results 
would be attained by the removal and fertilization of the 
ripe eggs from Plaice caught in the course of commercial 
fishing and the immediate return of these to the sea with- 
out having undergone treatment in the hatchery. We do 
not know whether this is practicable, and at any rate, the 
number of ripe eggs in the ovary of a Plaice at any one 
time is only a small proportion of the total number pre- 
sent. This method of obtaining eggs for the hatchery has, 
however, been adopted at times. The trawling vessels 
have been boarded on the fishing grounds and ripe fish 
have been “stripped, the eggs fertilized and taken to 
the hatchery. 
As we have seen the most striking fact in the life 
history of the Plaice is its limited range of migration, 
and this has suggested the possibility of recruiting a 
limited fishing ground in process of exhaustion, by plant- 
ing artificially hatched larve on it. The most economical 
method of obtaining the eggs would be from fish caught 
in the course of commercial fishing. Obviously the scale 
on which the hatchery would most effectively work would 
be determined by a knowledge of the annual reduction cf 
the fish population by fishing operations. 
