208 Transactions. — Zoology. 



insects besides. After hatching the young fry will be ready for turning out 

 into the rivers in from 30 to 50 days, and will carry best whenever they 

 begin to feed, which is from 25 to 28 days after birth. When they are 

 about six weeks old, if well fed, they average 1^ inches in length, and at 

 100 days three inches. Parr marks or dark bands distinguish the young trout, 

 just as in young salmon and sea trout, and in number I find these to be 

 from 10 to 13 ; but the same individual does not always have an equal 

 number on either side, just as they seldom or never have been found by me 

 to have equal numbers of spots on the gill-covers on either side of the head. 

 The parr marks disappear when the trout is four to five inches in length. 



In transporting these young fish, Mr. Deans prefers to do so when they 

 are from three-quarters to an inch long. He used to put water-cress into 

 the water in the cans, but more recently he has not used anything but 

 water, and has conveyed the young trout just as successfully the one way as 

 the other. The great objects to be kept in mind in this operation are cold- 

 ness and thorough aeration of the water, and also avoidance of crowding too 

 many fish into one can. The cans used are conical in shape, the base being 

 from 12 to 15 inches in diameter, and the top or mouth about 6 or 7 

 inches in diameter, and furnished with a lid which fits exactly. The height 

 of each can is about 15 mches, and it has a perforated false bottom fixed in 

 about one inch above true bottom. Aeration is generally found to be secured 

 by the motion of the railway train or other vehicle conveying the fish. At 

 other times a pannikin used occasionally will do as well. A can of the 

 above dimensions will carry about 500 young trout of one inch in length, 

 but that number should not be exceeded. 



On arrival at the river or stream destined to be the future habitat of the 

 young fry, they are liberated if possible in shallow water, with a coarse 

 gravelly or stony bottom. On their escape from the can to the river, they rest 

 for a time on the bottom, as if fatigued, thereafter going off according as their 

 instinct directs them. On one occasion in January, 1880, I remember in 

 company with Mr. Shennan, of Conical Hills, putting about 500 young 

 trout thus into a shoal part of the Pomahaka Eiver, and on our return in 

 a day and a half, we could not see a single one, not even a dead one, of 

 which there were some dozens at least. The river had been up a little in 

 the interval and was slightly discoloured, so possibly they had shifted their 

 quarters, or been compelled to do so by the action of the water. 



It need only be added here, that as it is believed that the stock in any river 

 will decrease (where fishing occurs) from year to year if left to itself, (indeed 

 the experience of Europe and America has demonstrated the fact), the 

 Otago society is very properly spending a large portion of its funds yearly 

 in those operations which I have given now in detail as above. Thus only 

 will the stock of trout in the rivers be maintained. 



