STOCKING TROUT STREAMS.

Press, Volume LXVIII, Issue 20450, 21 January 1932, Page 6

STOCKING TROUT STREAMS.

SUCCESSFUL METHODS IN AUCKLAND. PRY RETAINED IN PONDS. The success of the Auckland Acclimatisation Society in stocking its

rivers with trout was commented on yesterday by Mr A. W. Parrott, biologist to the Now Zealand Freshwater Research Committee, who has returned to Christchurch after a three weeks' tour of the streams in the Auckland Province. Mr Parrott attributed the Auckland Society's success to its methods of planting ova, of holding fry in ponds at the sides of streams for several months before liberating them, and of closing some rivers and stretches of rivers to anglers over several seasons. Five Months tho Best Age. "The Auckland Society liberates fry at the age of about five months instead of putting them into the streams at the usual time," said Mr Parrott. "It has been continuing this method since 1929, and has found it extremely successful. The best age for liberation has been calculated, as it has been found that the small fish are apt to become tame if retained for over six months. By this means the rate of mortality is very much reduced, as the fry can exist in security, safe from their enemies, until of a reasonable age.'' Mr Parrott referred to one such pond on the bank of tho Waipa river, near Otorohanga. Its measurements were 20 feet by 5 feet, and it was 21 inches deep. Last season this particular pond held 18,000 fry to start with, the number being reduced to about 8000 after four months. The fry were fed on eooked bullocks' livers, two being used every week. It was essential that the ponds should be looked after by somebody interested (e.g., some keen angler), for the fry should be fed once or twice every day. If so much care was not required, the system would be more widely used in Auckland. As it was, there were about seven ponds throughout the district. The Auckland Society planted about 440,000 ova every year, and liberated 156,000 fry through the pond system. The whole Bupply came from the Government hatcheries at Botorua. Well-stocked Streams. "All the streams in the Auckland Province are very well stocked with fish," he continued. "Generally speaking, the rivers are not fished so extensively as in Canterbury. There are few good roads giving access to the best fishing grounds; consequently very few anglers ever get to them, and there are some good fish to be found. There is not a decent fishing stream within 60 miles of Auckland, and local fishermen are inclined to go as far afield as Taupo to reach the big fish. Auckland anglers are very keen.

"The Auckland Acclimatisation Society is at present liberating purely rainbow trout, and has set free <io brown trout for five or six years. The distribution of the two types over the province 5s very interesting. Soma streams are exclusively full of brown trout, and some contain only the rainbow variety. However, the majority are now- rainbow streams, as the Auckland people seem to think this trout a bettor fish for angling. At Taumaranui the Wanganui river is stocked with about equal proportions of brown trout and rainbow trout. Further down the river there is a predominance of the brown variety; further up, at Xakahi, the proportion of brown is in the vicinity of 15 per cent.; further up still there are more brown in relation to rainbow; while, in the headwaters, thero is a marked predominance of brown again. This distribution is extremely peculiar. Good Spawning Grounds. "The upper reaches of most of the Auckland rivers make quite good spawning grounds," said Mr Parrott. "The Pokinui and Waimakuriri streams, which belong to the Waikato system, contain very good supplies vf. food. The fish are comparatively small, ranging from lib* to 2Jlb, but there are odd big ones. The Auckland Society has control of a very large tract of land —not taking in Eotorua and Taupo—and it is stocking systematically only about 45 or 50 streams. Certain streams, such as l the Waimakuriri, can bo used as nurseries, and they afford a more or less natural means of stocking other rivers. There is no doubt that it would be beneficial 'to close streams for certain seasons in other parts of New Zealand. The Auckland Society is liberating half as many fry as is being done in Canterbury and is getting excellent results." The methods employed in Auckland in planting ova and in liberating five months' old fry were both very satisfactory, said Mr Parrott, and it was to be hoped that something along the same lines could be accomplished in the South Island.