70 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



nevertheless, only catch a small fraction of the fish that are 

 there. Further on, after the plaice have become about three 

 years old, a small fraction of them migrate out into deeper 

 waters, beyond the territorial limits, and are caught by the 

 smacks and steam trawlers. Hitherto it is the fate of this 

 latter fraction of a per cent, of the whole plaice population, 

 annually coming into existence, that has been studied. Of the 

 fate of the plus 99 per cent, that perish before they are big 

 enough to be caught by a trawl-net we know hardly anything. 

 A very few, then, of the plaice that can be taken in a 

 shrimp-trawl migrate out to sea, become big, valuable fish, 

 spawn, and are sooner or later caught. This fraction consists 

 of individuals that have greater " vitality," grow more rapidly, 

 are more " restless," and are more precocious in their assump- 

 tion of sexual maturity than are the average fish. The mediocre 

 individuals — which constitute by far the greater number — are 

 less variable, and they tend to remain longer on the over- 

 crowded nursery grounds, where they develop and grow slowly. 

 How to assist them in obtaining better conditions of life may 

 well be the great task of fish culture of the future, and all 

 experimental and observational work and all practical trans- 

 plantation operations help to solve this problem. Then there 

 is the greater problem of the utilisation of surplus, " waste " 

 production. The substance of the hundredweights of plaice 

 that die in the sea uselessly (in contrast with the ounces that 

 are caught usefully) is not lost, but appears later in the forms 

 of crabs, molluscs, worms, starfishes, sea-weeds, and a multitude 

 of other organisms that have — as yet — no commercial signifi- 

 cance for us : at the most we think about them as a possible 

 form, or source, of manure ! Fishery work of the future will 

 probably be dominated by the impulse to utilise the waste 

 production of the shallow seas, just as that of the past has been 

 obsessed by the fear of depletion and has resulted in successive 

 crops of restrictions of very doubtful value. This idea of 



