Living Silver 



dertaken journeys of up to a hundred miles . Usually they had been 

 moving north. But these experiments did not altogether dispense 

 with the idea of isolated bay communities, for most of the fish 

 that were observed to have travelled these considerable distances 

 were oldish fish, at least old enough to have spawned or to be 

 ready to spawn. It therefore seemed conceivable that the newly 

 settled plaice gathered in shallow inlets where they fed quietly 

 and without travelling out of them until the sexual urge drove 

 them toward the deeper off-shore regions. There, perhaps even 

 in the course of spawning, a mixture of populations took place 

 and, if any individual fish made toward the shallows, it might well 

 end up in a different bay from that in which it had originally mat- 

 ured. But the very largest fish kept to fairly deep waters. 



If all this were admitted, there still remained the problem of 

 growth rate differences in proximate bays, but these could be sim- 

 ply accounted for by supposing that certain stretches of inshore 

 water were rich in the invertebrate life upon which the plaice fed 

 while others were poor in it. If a single fish happened to be lucky 

 enough to undergo metamorphosis from round larva to flat fish on 

 one of the rich grounds, then it would grow more quickly than its 

 more unfortunate blood brother that had been carried by a freak 

 of the sea currents to a neighbouring inlet where few invertebrates 

 lived and where, perhaps, many other young plaice were already 

 hunting for them. In this interpretation, food became almost as 

 effective in defining races within a species as genetic differences 

 were usually taken to be. 



Jan was fond of plaice. He imagined their stippled bodies slid- 

 ing with feathery smoothness but cold as a dragon over the sea- 

 bed, each gulping its wormy or molluscan prey. No account of 

 its bionomics, however, internecine or otherwise unprepossessing, 

 ever damped his enthusiasm in the sheer beauty of the fish. The 

 cleft ridge of its brow was almost sagacious. It was imprinted on 

 the sea floor, regally like the seal of a king, its colours rich, lively, 

 unquenchable, the colours of a philosopher who knew life to be so 

 evil that there was nothing to do but rejoice. The plaice was al- 



I02 



