198 Transactions. — Zoology. 



Art. XXI. — On Diseased Trout in Lake Wakatipu. By W. Arthur, C.E. 

 [Read before the Otago Institute, 15th August, 1882.] 

 Plate XXIII. 

 For several years back the large trout in Queenstown Bay, Lake Wakatipu, 

 have been a subject of notoriety and interest to visitors and others. These 

 trout, in weight from 2 lbs. up to 15 lbs. or more, and in shoals of several 

 hundreds, frequent the east margin of the bay near the mouth of the Town 

 Creek, the reef at the end of the Peninsula, and the shore near the One- 

 mile Creek on the west side. They appear quiet and lazy in habit, except 

 when, as often occurs, they throw themselves with great vigour into the air. 

 It is also to be remarked that they are to be seen at these places both in 

 summer and winter, caudal and dorsal fins on the surface, and an occa- 

 sional one may also be observed in the middle of the bay or at the steam- 

 boat jetty. The water is very deep throughout this bay, but has a shallow 

 margin a few yards in width running round parallel to the beach. The 

 great body of the lake itself is abysmal, the only sounding got as yet being 

 at a depth of 1,300 feet. Along the east side of the Queenstown Bay there 

 is a belt of weeds growing on the bottom on the outer edge of the aforesaid 

 shoal-water, the bottom itself consisting of shingle, gravel, and sand. The 

 water of the lake is remarkable for clearness and purity, and is snow-fed 

 through the Dart, Bees, Greenstone, and such rivers, which drain the sur- 

 rounding mountains of the Southern Alps. Dr. Black, of our University, 

 remarks, on his analysis of this water, that he never examined any water so 

 destitute of common salt — a fact of great importance as regards the health 

 of trout. His analysis I may repeat is, — 



Organic Matter in Solution. Table Salt. Degree of Hardness. 



Wafcatipu — 0'5 grains per gallon. Scarcely a trace. 3-1 degrees, very soft. 

 In summer storms are frequent on the Wakatipu, but in winter its surface 

 is generally calm or nearly so. The trout S. fario, ansonii, Gunther, were 

 put into the feeders of the lake about the year 1874. 



Besides the abnormal habit of great trout herding together in shoals, 

 these Wakatipu fish almost without exception have refused the baits of 

 anglers who have fished for them. The exception I refer to is that of a 

 beautiful but small trout of l£ lbs. weight, taken by Mr. J. P. Maitland with 

 minnow, while fishing from the beach of Queenstown Bay in January, 

 1880. This fish was remarkable by its bright silvery scales, the absence of 

 all spots excepting on one gill-cover, and the absence of teeth on head of 

 vomer. The condition generally of these trout is suggestive of good living, 

 as they are fat and sometimes very much so, and are said to possess excel- 

 lent edible qualities. But for some years I have heard of the presence of 



