80 
different boats, and so affect the result. At the best, it 
‘an only be an approximation that will be obtained; but, 
still, it can searcely be doubted that the annual destruc- 
tion 1s enormous, and that the young flat-fish so lost are 
potentially very valuable. It seems probable that the 
total annual destruction of young fish by shrimping in 
our district 1s to be measured by the hundred million. 
We know, moreover, that the Lancashire shrimping 
grounds constitute our most valuable fish nurseries, which 
bear a definite and important relation to the fishing 
ground off-shore, and we may assume that if young fishes 
are allowed to grow undisturbed on the in-shore nurseries, 
they will later on become marketable fishes on the off- 
shore fishing grounds. We may state also that as all the 
common. flat-fish pass through a stage in which they 
inhabit a shallow-water area, the number of marketable 
fishes on the off-shore grounds will vary as does that of 
the small fishes in the nurseries. If, then, we are able to 
protect our young fishes in the coastal waters, under 
ordinary circumstances they should turn up a year or two 
later on the grounds outside. The preservation of 
immature fishes ought to be very beneficial to the off- 
shore fisheries more beneficial even than the preserva- 
tion of spawn, because the mortality during the period 
between hatching and the stage when the young fishes 
make their appearance im the nursery is so very great that 
a given number of young fishes represents many hundred 
or thousand times that number of eggs or embryos. 
Now, this a prior? argument is probably quite a 
good one, and if we had no other means of investigating 
the matter, we should probably be justified in relying upon 
it. But the points enumerated in the last paragraph in 
relation to the life-history of the fish, are eminently suit- 
able for biological and statistical investigation. And it 
