SALMON— DISEASES OR CAUSES OF DESTRUCTION. Ill 



may be popularly termed minute p^crms or seeds provided with cilia, rendering 

 them capable of spontaneous motion, may become dillused tlirough the water. 

 These germs * arriving at a suitable spot develop into a fungus, and such a 

 locality is fouml in au}' abraded spot on the body of a fish, where its roots strike 

 downwards into the llesh and its free extremities come to the surface, forming 

 the white fungus which has been aptly compared to the appearance of a piece of 

 cotton- wool in water or a white furry spot, and is so destructive to li.sh suliering 

 from this disease, consequent on exhaustion, irritation or suffocation when the 

 respiratory organs are affected. 



(4.) Misplaced energy in fishing, or the work of the poacher, is often very 

 detrimental f to salmon fisheries, but is a subject which must be separately consi- 

 dered. While legislators ought to clearly understand that increased present 

 productiveness may be carried on at the expense of future years' supply, and that 

 multiplying modes of destruction does not invariably tend to the benefit of either 

 the fisherman or the consumer, also that leaving merely young or undersized fish 

 to continue their race is a potent means of fisheries deteriorating. 



(5.) Injuries occasioned by the lower animals ai'e numerous, and differ con- 

 siderably in the adult stage from what they do among the ova and young. Along 

 the sea coasts, in estuaries and the mouths of some rivers, porpoises, seals, gram- 

 pusses and their allies commit great havoc among salmon and grilse. While in 

 rivers especially, or spawning beds, otters are very destructive ; but they are 

 credited wdth destroying eels, which are very detrimental to these fisheries. Some 

 also believe that they act serviceably by capturing weak and diseased fish as they 

 come on to the shallows, in a debilitated condition, and so curtail the spread of 

 disease, but on the other hand some hold that they prefer healthy to diseased forms. 

 Irrespective of mammals and birds which have been alluded to as detrimental to 

 eggs and young fish (p. 28 a7ite) there are some birds that likewise attack adult fish, 

 as the great black-beaked gull, Larus marhms, which on account of its well-known 

 partiality is termed a "salmon gull " by the fishermen, in the lower reaches of 

 the Severn. This river falls with great rapidity, while owing to the shifting nature 

 of its sands its course frequently alters and consequently it is not uncommon on 

 falling tide for salmon to be left in a backwater. Now these gulls at once attack 

 and kill them, commencing by picking out their victims' eyes with their powerful 

 bills. Many forms of birds and fish will also eat the young salmon smolts ; and at 

 the mouths of some rivers, as that of the Tweed, so many are destroyed by the 

 coal-fish, Gaclus virens, termed "podles," that men are employed to destroy these 

 members of the cod family as vermin. J Trout, as has already been observed, are 



* Mr. Murray experimented upon fish which were inhabiting aquaria at South Kensington, and 

 suffering from Saprokguia ferax, although the fungus was not present in the water suppUed. He 

 found this fungus in some earthworms which had been obtained from outside the Museum, where 

 the bones of fish which had died of this disease had been buried, and from which spot worms had 

 twice been obtained to feed the aquatic animals in the tanks. Mr. Murray concluded that "the 

 agreement thus established forces upon me the conclusion that the infectious material was 

 obtained from the dead fish cast out : that during the damp weather it remained alive in its resting 

 state, and was spread about by earthworms, and that it was finally conveyed by them into the 

 tanks where the outbreak took place." — Annual Report of Inspector of Fisheries. 



t On the other hand respecting this disease a correspondent of Land and Water remarked: 

 " In the good old days when ' waters ' let at as many pounds as they now do hundreds of pounds : 

 when every man leistered and netted and burned and fished as suited his own pleasure : when 

 close time was unknown, and fish were killed on the spawning beds by thousands, there were 

 twenty fish at least \yhere there is now one." To this it was replied, that even supposing over- 

 crowding were injurious, the cause of that overcroAvding in some rivers cannot be due to over 

 preservation ; the number of salmon and grilse having steadily diminished in the Tweed from an 

 annual average of 37,485 in five years, 1854-58, to 25,988 in the five years 18G9-74. 



X It has been suggested that swans might be useful in salmon streams, or rather lakes, in 

 order to devour the enormous masses of ova of perch and pike, and so diminish their predaceous foes. 



"Nahanik," in Land and Water, September 20th, 188G, observed of the salmon, that " there was 

 a river in that district, a tributary of the Shannon, famous for salmon and white trout. In my 

 boyish days these fish were killed in every way. There were eel weirs on every ford, and, when 

 the salmon and trout were running, they were caught in thousands at the weirs, or were speared 

 by torchlight. Between 1840 and 1850 all the eel weirs were taken away by Act of Parliament, 

 and afterwards all the salmon and white trout disappeared. I took a great deal of trouble 



