228 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
These defects may be remedied by using a silver label 
and a silver disc in place of the button, and such a 
modified mark may be recommended to those who are 
anxious to avoid all possible sources of error in method. 
The amount of inconvenience or actual injury to 
the health of the fish caused by the attachment of the 
mark has probably been over-estimated in criticisms of 
the methods. It is very seldom that I have seen an 
enlarged and ‘‘sore’’ wound when the above method of 
marking was adopted; and I have never seen any 
indications of septic infection—a result that might have 
been anticipated. It has been suggested that the attach- _ 
ment of the mark may cause the fish to behave 
abnormally; to migrate along unusual paths; or perhaps 
retard the development of the reproductive organs, or 
inhibit the growth of the fish. I do not know on what 
experience these effects have been apprehended; certainly 
I have seen nothing that would lead one to expect that 
they would occur. It is quite probable that a certain 
proportion of the fish marked die after lberation, but 
this 1s because they have been injured in the trawl net. 
In a good experiment from one-quarter to one-half of 
the total number of fishes liberated are returned, and 
when one considers that many marked fishes are 
re-captured but not returned, while others are doubtless 
destroyed by their natural enemies, it is apparent that 
the marking operation is not prejudicial to the health of 
the fish. Further, a fair proportion of marked fish are 
returned after having been at large for a period of one 
_to three years, and these have usually become mature, a 
fact which does not indicate that the mark is harmful 
to the fish. 
It has been urged that marked fish may be 
liberated and then recaptured before they have had time 
