314 BRITISH FISHERIES 



in correct practice they should be set free (i) in 

 such a place that the surface drift will carry 

 them to the nursery grounds, and (2) so that 

 the duration of this inshore drift will coincide 

 with the duration of the period between the stage 

 at which they are liberated and the stage of the 

 metamorphosis. 



In all economic sea-fish cultural operations, the 

 intention is to benefit some particular local area. 

 To be certain of doing this, it is further necessary 

 that we should know that the migratory course 

 pursued by the young fishes added to the inshore 

 nursery is such as will carry those fishes, when 

 they become marketable, from the latter to the 

 fishing grounds offshore. 



Now, a consideration of the literature of sea- 

 fishery science will show that, so far as this 

 country, at least, is concerned, we do not know 

 enough of the migrations and distribution of 

 fishes at all stages, to be sure that all these con- 

 ditions may be satisfied. In actual practice, 

 moreover, questions of expense must be con- 

 sidered, and it is not generally practicable to 

 liberate the larvae on the offshore spawning 

 grounds, at the times when winds and currents 

 contribute to secure the most favourable inshore 

 drift for the fry liberated. The best has to be 

 done, and this is not always the theoretically 

 correct (so far as we know) procedure. 



There are two main arguments for the utility 



