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THE SALMON DISEASE.* 
By W. G. Smith, F.L.S. 
For several weeks past the newspapers have contained accounts 
of the diseased condition of various fish in several of our northern 
rivers — principally the Esk and Eden. The disease of the fish is 
caused by an attack of a fungus, and therefore must have some 
interest to your readers. No doubt every one with a slight acquaint- 
ance with fungi suspected from the first that the disease was similar 
to the familiar disease of goldfish in aquaria, and no other than the 
common Saprolegnia ferax. From material kindly forwarded to 
the writer for examination from Carlisle by Mr. George Brookter, 
of Huddersfield, there seems to be no reason to doubt the identity 
of the parasite with the common pest of carp — Saprolegnia ferax. 
According to the newspaper reports we find that the owners of 
the salmon fisheries on the Tweed, and the Commissioners to whom 
the protection of the fisheries is entrusted, have for years been 
disturbed, distressed, and annoyed by a great mortality which comes 
over the fish towards the end of the spawning season. Any time 
during February, and anywhere between Stobo and Berwick, dead 
salmon may be seen by the half dozen in every pool. The epidemic 
is thus described : — Large numbers of salmon — not only kelts, but 
clean fish lately arrived from the sea — appear to be affected with an 
epidemic which destroys hundreds of them. The head and tail first, 
and gradually the whole body is attacked by a disease which ap- 
pears to eat away the flesh, turning it white, and giving the fish 
the appearance of being affected with the leprosy. Such fish are 
entirely unfit for food. Correspondents describe them as leaping 
out of the water, as if in pain and in frantic efforts to escape ; 
some return to the sea, but many perish in their attempts to reach 
the salt water. The salmon caught in the estuary are not diseased 
in this way, and, as the epidemic is said to be spreading to the 
trout, it would appear that some peculiar condition in the fresh 
water is the cause of the remarkable phenomena. Some of these 
characteristics of the disease are not confirmed by a more correct 
observation and less hasty deduction, but what is said enables one 
to recognise the malady which for several years past has slain its 
thousands of salmon on the Tweed. In both rivers the afflicted 
animals suffer violent pain, and rush blindly about as if brain dis- 
ease existed through generally inflammatory action, and in both 
rivers the dead bodies present a similar appearance. 
The various theories which have been published in the daily 
papers as to the cause of the disease and the “cause of the fungus” 
have no foundation in fact. The most common theory seems to be 
that the salmon die irom disease induced by inflammatory action 
arising from retention of the milt. The theory of the fishery 
* By permission from the “ Gardeners’ Chronicle,” May 4th, 1878. 
