The causes of these fluctuations is an interesting, scientific 

 problem, and one which may be solved — given sufficient 

 resources for investigation. 



(2) Ejfect of War-time Restrictions on the Fishery. 



There is no evidence that the mihtary restrictions, in 

 operation in the Irish Sea in the years 1914-1918, had any 

 observable effect on the abundance of the plaice there in 

 1919-1920. 



(3) Size-limits for Plaice. 



There is no evidence that a size-limit for plaice that may 

 legally be landed would have any effect on the abundance of 

 commercially valuable plaice on the Irish Sea fishing grounds. 



A word or two may be said about what we regard as 

 " evidence." // the Irish Sea plaice grounds are being 

 impoverished by too much trawling ; if the military restrictions 

 of 1914-1918 led to an accumulation of plaice in the Irish Sea, 

 and if a size-limit could be shown to be useful in preserving 

 the plaice grounds from impoverishment. Then the practical 

 outcome of these findings would be administrative restrictions. 

 These restrictions would create new legal offences, punishable 

 by fines or imprisonments. 



Therefore the scientific evidence that would justify us in 

 making administrative restrictions and by-laws ought to be of 

 the same nature, or just as convincmg as would be the evidence 

 required by the police courts for the conviction of a fisherman 

 who would infringe these by-laws. We know what is the 

 nature of the latter evidence, and we hold that the results 

 obtained from these investigations have not the same degree 

 of strength and ought not to be used for the establishment of 

 new legal offences. 



But the results that have been obtained may be strong 

 enough to justify a fishery authority in spending money on what 

 may be called fishery development. We do not say that it is 



