ANGLING

Otago Daily Times, Issue 23364, 2 December 1937, Page 5

ANGLING

By Dry Fly COMPETITIONS December 4.—Waikouaiti River; any bait; hours 6 p.m. till midnight. February s.—Pomahaka River; any bait (anglers’ outing); hours 5 p.m. till midnight. February 6.—Pomahaka River; dry fly; hours 7 a.m.-3 p.m. February 26.—Shag River; bare fly; hours 5 p.m.-midnight. March 27.—Waipori River; any bait; hours 9 a.m.-6 p.m.; weigh in at Berwick store at 6.30 p.m. The following cups will be competed for: —Finlayson Memorial Cup, Levido Cup, Spears Memorial Cup. Griffiths Cup. In conjunction with the Pomahaka River outing, an eeling competition will be held. CATLINS IN GOOD ORDER A correspondent of the Otago Acclimatisation Society advises that the Gatlins River is in splendid condition at present, and that good catches of trout are being obtained. The season so far at the Manorburn dam has proved highly successful (writes a correspondent.) ‘ The fish are small in comparison with those of other years, but are in excellent condition, I secured 48 good rainbow one weekend and 25 the next, and 22 next. Recently three rods secured 119 fish tor four days’ fishing, but the worm bait was the most successful. This is an ideal spot for a camping holiday, but campers should take Primus stoves, as there is no wood available. NORTH OTAGO FISHING The Waitaki River rewarded anglers over last week-end with a .bountiful supply of fish in good condition. The mouth yielded very few fish, but further back near the bridge better success was met with, the largest brown trout caught weighing 121 b. Reports from other parts of the Waitaki indicate that anglers were successful, the river being fairly low and in excellent condition. The Kakanui River is fast drying up, and at the moment is well-nigh covered with weed and slime. Little fishing has been done at this river for some time, chiefly owing to its low state. A competition held there recently was productive of only a few small fish, the best bag weighing 31b. NATURAL REPRODUCTION Anglers have on occasions complained that they are not getting value for the money spent on research, and are continually inquiring what the research workers arc doing. .Those; anglers should read and study jU s !l" eries Bulletin No. 6,” by Mr D. F. Hobbs .and they will be satisfied tnat dm ing the years* 1932 to 1934 Mr Hobbs certainly was not idle. The bulletin

is entitled’ “ The Natural Reproduction of Quinnat Salmon, Brown and Rainbow Trout in Certain New Zealand Waters.” English and American pisciculturists have written on this subject, but Mr Hobbs’s work certainly discredits many statements made by these writers. Mr Hobbs quotes statements as to the inefficiency of natural reproduction from writings by Francis Day (“British and Irish Salmonidae”), Armstead (“An Angler’s Paradise and How to Obtain It”), Rutter (“Natural History of the Quinnat Salmon —Bulletin United States Bureau of Fisheries”), Bobcock (“ Some Experiments in the Bureau of Salmon Eggs”), and Mosley (“Insect Life and the Management of a Trout Fishery”). He then points out that although these writers assert enormous losses occur in artificial reproduction they give no supporting evidence to justify their statements. The only thorough investigation, apart from the present bulletin. has been made by Forester at Cultus Lake. British Columbia, and his final results are not yet published.

This bulletin will certainly cause , a stir and possibly some controversy in Britain and America, and it will be interesting to see the reception accorded to the bulletin abroad. The work has been done so carefully and thoroughly however, that it seems Mr Hobbs has built up an irrefutable case for his conclusions. It will be noted that this present bulletin does not coyer the work done in Southland during the last three years. This work will be the subject of a later paper, and local anglers and others will look forward to this futher publication with much interest. It may be assumed, that this later work will complete the investigations in this aspect of research and make definite conclusions available. Mr Hobbs states that the data presented justifies the following conclusions, inter alia, about the areas examined:— 1. The efficiency of fertilisation of the eggs of quinnat salmon and of brown and rainbow trout, lodged in natural redds in streams is remarkably high. Material from redds of brown trout showed an efficiency of fertilisation in excess of 99 per cent. 2. Heavy losses of fertilised ova are the outcome of adverse environmental conditions and not of inherent weakne|.S The extent of losses of fertilised ova in undisturbed redds 'depends primarily on the amount of very fine material in the redds during the development of ova before eyeing. It is possible that high water temperature is a contributing cause of loss. 4. Losses, of unmeasured extent, of ova of brown trout occur through the superimposition of redds where suitable spawning areas are of insufficient size for the number of fish which occupy them. , , , , 5. All floods tend to be harmful in that they increase the deposition of fine material in redds. . 6. Floods rarely effect the substantial modification of the contours of redds. When they do so they may cause losses considerable enough to account for the partial failure of a year class. ~ .... 7. Under favourable conditions natural reproduction is a highly efficient process. . 8. The fact that favorable conditions were found to exist not uncommonly in streams in a belt of country embracing a great variety of conditions suggests that the efficiency of natural spawning of Salmonidse m New Zealand may be generally higher than was heretofore supposed. The practical application of the work is indicated as follows: —“This paper is essentially a preliminary study. No recommendation of immediate practical importance in conservation of stocks of fish follow from the observations made. A substratum of necessary knowledge has been built up. The application of this knowledge to practical problems is a second and distinct phase of the work. ... . “In the main it is the policy of authorities controlling inland fisheries

in New Zealand to trap wild fish,-;.’ where they can be obtained convcni-'- ' ently and in sufficient numbers. The** ova are obtained, fertilised, and"-' hatched under artificial conditions,' "■ The resultant fry are liberated, j redly about the time all yolk is ab-J* 5 sorbed. The data presented in this report provide no ground either for,.], recommending modifications of exist-’,-. ing policy or for approving it. “It is clear that knowledge of prac-.v? tical value to fisheries authorities should result from an extension of this work.

“It is obvious that only a very small; proportion of the eggs produced, by, .! Salmonidae can develop into mature fish. The work of White on the Ameri-,,-, can brook trout showed that a tre-Vh mendotis mortality occurred in the first d few months following the absorption. ~ of the yolk-sac when young fish were"" liberated from artificial hatcheries into controlled areas of natural streams. It, 1 ! is possible that the present system oiK fish hatchery operations in New Zea-£ * land safeguards the young over a-:, period through which they are much;, - less in need of protection than in an ’ equal period of time immediately fol-?. lowing their liberation. The truth this matter needs to be ascertained.” In conclusion, it must occur to thinks \ ing readers that the finished work now,' t published gives no indication or hint?' of the physical and mental endurance*], of Mr Hobbs in collecting his material) J and sorting and investigating it. It in-*, volved living for many months the life< j practically of a hermit in the \ frozen valleys of the Southern Alpsjn during the severest weather of and working all and every day in the], icy cold water of the Broken River] * and other streams and with a heavy.? * pack to carry samples in addition to t tools and so on. Then, after working J all day, the investigator had to return j after dark probably several miles over .* bush tracks to his lonely cabin at * Avoca and light a fire and prepare his evening meal. Then, after a meal had been prepared and disposed 9f, fireworker had to work until midnight or later examining his specimens and writing up his record, etc. --1