100 NORTH SEA INVESTIGATIONS. 
injuries are sometimes trawled. Moreover the very small mesh of 
the shrimp-net appears to lessen the percentage of chafed fish, since 
it is in struggling to get through larger meshes that injuries to this 
species usually occur. 
Plaice of all sizes suffer no injury from bemg caught in the 
shrimp-trawl, and may even be allowed to lie on the deck a consider- 
able time without being any the worse. ‘There has been very little 
mortality amongst a great many of all sizes which were placed in the 
Cleethorpes aquarium, whereas I have always experienced a difficulty 
in getting similar specimens, taken in the shove-net, to live. ‘This 
may be due to the amount of mud and sand in suspension in the 
only water available for conveying shove-net specimens to the 
aquarium, or it may be that the buoy of the shrimp-trawl is bene- 
ficial in slightly lifting the cod end off the ground. 
Flounders are about as hardy as plaice under similar circum- 
stances. 
Dabs, unlike plaice, will not survive a long exposure on deck, the 
very small specimens being particularly delicate. The mortality 
amongst those sent to Cleethorpes was at first considerable, though 
a good many survived. Still, if they are returned to the sea at 
once, they dart away apparently uninjured. ‘This species appears 
even more susceptible to injuries arising from chafing than the sole. 
Conclusions.—It appears to me that the facts I have set forth 
show that capture in a shrimp-trawl in the ordinary course of the 
industry is not essentially injurious to any considerable proportion of 
young fish of marketable species. If shrimp-trawlers bring to 
market some small plaice and soles which ought really to be 
returned to the sea, it is not easy to blame them as long as the 
same practice, as far as plaice are concerned, is carried on with 
perfect impunity on an infinitely larger scale by the larger boats 
which visit the eastern grounds, ‘The remedy for this evil les so 
evidently in the imposition of a size-limit applicable to all North 
Sea fisheries alike that the subject needs no discussion here. More- 
over it is apparent that the bulk of the small flat-fish, which, for 
reasons explained at the time, I found it necessary to class as 
caught by shrimp-trawling, were in reality derived from the illegal 
use of fish-trawls. 
I have made it, I hope, sufficiently evident that, except off 
Tetney, flat-fish are so exceedingly scarce on the prawning grounds 
that there is not even the risk of them being injured thereon. 
I am not prepared to say that, in the case of so large a catch of 
small fish as has been enumerated from the Sand Haile shrimp- 
ground, some considerable number of small dabs and, to a less 
extent, plaice, might not have suffered, since to sort them out would 
