Appendices to Twenty-fourth Annual Report 



APPENDIX V. 



" THE WHITE SPOT " AFFECTING SALMON IN THE 

 ISLAND OF LEWIS. 



Through the kindness of Mr. George Pople, the tenant of the 

 Grimersta fishings on the west side of Lewis, I have received several 

 specimens of fish and heads of fish showing this peculiar ailment. It 

 occurs in fish which, owing to dry weather and the shrunken state of 

 the streams, are unable to leave the salt water but remain for a 

 considerable time in the shallow bays. When the streams become 

 sufficiently swollen after rain to admit of their ascent in fresh water, 

 " the white spot " disappears. The only reference to this disease of 

 which I am aware is in Scottish Moors and Indian Jungles, p. 141, by 

 Captain J. T. Newall, who was at one time tenant of Scaliscro shootings, 

 just south of Grimersta. It is as follows : — " The summer in the Lews 

 " in 1880 was remarkable for the unusual heat. Salmon, in consequence, 

 " could not ascend the rivers, which became so attenuated as to afford 

 "no waterway for them. Fresh water being equally necessary as sea 

 " for the health of the fish at the proper season, they suffered in 

 " consequence. Many became quite blind, and developed a white spot 

 " on the head, the result being the death of numbers near the mouths 

 " of rivers." The natural inference is that the lack of fresh water is 

 responsible for this trouble. This I consider very unlikely indeed. 

 The blindness, the bright sunshine of hot weather, the perfect trans- 

 lucency of the sea water around these western islands, and the shallow 

 nature of the estuaries or bays in which the fish congregate, seem to me 

 to suggest a diffierent cause. One is reminded of the pale-skinned, 

 sightless condition to which fish are reduced when confined too long in 

 aquaria exposed to sunlight. When in Stornoway in 1902, I was 

 informed by a former gamekeeper at Stornoway Castle, the present 

 lessee of the Royal Hotel, that in summers w r hen this disease is really 

 bad, the fish become so helpless that boys stone them and drag them 

 ashore in the neighbourhood of the harbour, but it is evidently unusual 

 for fish to become blind or to die of the disease. Mr. Pople, in sending 

 me the specimens referred to, informs me that he had never seen a fish 

 dead from this cause. The summer of 1905 was unusually dry, and one 

 of the specimens sent was described as the worst Mr. Pople had seen 

 during his tenancy. The dull white appearance had developed into a 

 raw red sore. The significant remark is also made in a letter of 

 14th August, "although we have had it very dry it has been more or 

 " less cloudy and windy, it (the disease) would have been worse in 

 " brilliant sunshine and light east or no wind." The accompanying 

 figure represents the head of one of the specimens received from 

 Grimersta, and shows the early or " white spot " condition of the ailment. 

 The specimen was killed on 14th August, and represents, I believe, an 

 average state of the peculiarity. The skin is unbroken, the white area 



