INTRODUCTION. xxv 



On the subject of the fungoid growth known as Saprolcgnia fcrax affecting Salmon, I 

 cannot do better than quote the remarks of my friend, Mr. W. G. Smith, a very competent 

 authority on all questions relating to mycology. He writes: — 



"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 the attack of a 

 fungus. No doubt every one with a slight acquaintance 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 appears to eat away the flesh, turning it white, and giving the fish 

 the appearance of being affected with 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 suff"er violent pain, 

 and rush blindly about as if brain disease 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 from 

 disease induced from inflammatory action arising from retention of the milt. The theory of the fishery owners and 

 the Commissioners does not afford even the small consolation that the fish die a natural death, for they hold, and 

 are ready to affirm on oath, that the vile pollutions of the woollen mills and towns on Tweedside cause all the evil. 

 The controversy has continued for years, but now some facts have turned up in Cumberland and Westmoreland which 

 must carry a verdict of acquittal for the millowners. A short time ago large numbers of dead Salmon were found 

 in the Kent, a river which is as pure as Thirlemere itself. No pollution, wilful or accidental, could be traced, and 

 the authorities had to confess their ignorance of the cause of death, coming to the illogical conclusion that it arose 

 from exhaustion after spawning, oblivious apparently that this has happened every year since Kent was a river, and 

 the deaths have been heard of only now. From a statement in the Times it appears that things piscatorial are much 

 worse in the Eden, which flows through a beautiful country guiltless of the offences of factories. 



The Carlisle Journal says, 'Large numbers of kelts — that is, fish that have spawned — are found in pools and 

 floating down the stream dead and dying. The appearance of the disease is that of a white fungus. This affects 

 the head of the fish, then it attacks the tail, and subsequently the fins. In some instances the fungus grows so 

 plentifully that the fish appears to be swimming about with a white nightcap over its head. Salmon smolts and 

 Trout are also affected by the disease. An unusual number of kelts have remained in the Eden this year, and many 

 of them have died; so many, in fact, that the water bailiffs have been employed in picking them out of the water 

 and burying them.' 



This disease is by no means confined to Salmon and young Salmon (smolts), but Trout, Eels, Lampreys, Flounders, 

 Minnows, and other fish, are equally affected. A watcher on the Esk informed Mr. Brookter that the disease nearly 

 always starts at the nose, and gradually spreads over the head; the fish, he affirmed, would come to a still part of 

 the river with only a small patch on the nose, and in two or three days the patch would have extended over the 

 head, and at the same time have appeared on the base of the fins and tail. The disease is said to be generally 

 confined to the parts mentioned, unless the fish has had a bruise or scar anywhere so as to remove the scales. From 

 an examination of actual specimens, however, it seems proved that the disease by no means always commences at 

 the head. With a very low power of the microscope the fungus will be seen to consist of a dense mass of matted 

 threads without joints, and a thick forest of minute transparent clubs. 



If asked for a reason for the uncommon abundance of the fungus this year, I should be inclined to refer it to 

 the extraordinary mildness of the late winter. Severe weather, or a sudden change of temperature, will generally 

 collapse fungi of the nature of Saprolegnia ferax, as will several dilute chemical infusions, and that without damaging 

 the fish ; but an experiment, though successful in an aquarium, might possibly fail in a large river. 



The fungus has been described as infesting the dead, as well as the living, fish; but with me the fungus has 

 invariably vanished with the death of the fish. Dead fish are certainly covered with a white cottony coating, but 

 on an examination of this flocculent mass, under the microscope, it is found to consist wholly of white granular 

 matter, consisting of bacteria, monads, etc., and no fungus threads or fruit belonging to Saprolcgnia fera.x can be 

 seen. 



The disease has been so virulent on the Esk, during the present spring, that the watchers have in some instances 

 buried as many as three hundred and fifty fish in three days between Langholm and Longtown." — Gardeners'' Chronicle, 

 pp. 560-5G1, 1878. 



