ANGLING.

Otago Witness, Issue 3030, 10 April 1912, Page 64

ANGLING.

By Jock Scott.

To be a perfect fisherman you require more excellencies than ore usually to be tound in such a small space as is allotted to a man's carcase. — Pahkeii Gilmour. Readers are invited to contribute items of local fishing news for insertion in this column. For Insertion in the ensuing iaßue they should rjueh Dunedln hy Monday night's mail.

«ANK NOTES. An Old Poacher. For four or five years (writes a correspondent), a large eel has made his homo under a ledge near the read bridge over the Waikouaiti River. On one occasion two Dunedin anglers saw this monster in the act of swallowing what appeared 1 to be a 2il> trout. On the night, of Saturday, the 30th March, Mr Gillespie employed with Messrs A. and W. M'Cirthy, managed to capture this old poacher. Ho was landed after a big fight, and when weighed turned the scale at His length was 4ft sin and his girth 16in. The Waikouaiti.—On Saturday, the 30th March, Mr Wa;»J, of Merton, caught four nice iish in the Waikouaiti River, using the cocka bully ais a lure. It is reported that there are a lot of gowl fish in the river up to Cherry Farm ; that they are mostly 21b fish, and are full of spawn. Jf this is so, it. would' appear that the extension of the angling season t-o the 30th April is a mistake. The Molyneux.—l am given to understand that some good Hah are being caught in (lie Molyneux River, which i :i jr s lower parts is full of whitebait. Road Treatment and Fish Life. "The Relation of Modern Road Facings on Fish fiife" is the title of an interesting paper presented bv Mr W. J. A. Butterfield before the Institution of Municipal and County Engineers at Home recently. After touching briefly on the general cities tion of load surfaces, which until quite recently were almost entirely wa teibouiul macadam, and which per se may be dismissed as having no i>ernicious effect on watei coursed, his goes on to discuss the materials used for abating dust. Two of them. sea water and calcium chloride, are considered, and finally pronounced harmless. Sea water, however, "was generally discarded after trial." As for calcium chloride, ''this Rait, when dissolved in water in the proportion of one part of calcium chloride to 1000 parts of water, has no effect on fish (gudgeon).*' Mr Butterfield says that it is extremely unlikely that so strong a solution would ever get into a water from a road treated with calcium chloride, and adds: "It maj be inferred that calcium chlorido may be applied to roads for du«t abatement without risk of ill-effects on fish life in the streams and' ponds of the district." When we come to tar, however, another verdict has to be given. Mr Butterfield considers the different kinds of iar—coal tar, oil lar or wafer gas tar. blast furnace tar, and producer tar —and dis cusses their constituents, which are. of course, very important to the inquiry, Inasmuch as Rome of them are highly injurious to fish. Exn-eriinonU v - *:-* conducted to see how far these. component parts of coal tar (ammoniacal liquor, tar oils,

and pitch) affected fish, which wen; put into u glass vessel holding live or six gallons of tne solution which was being tested. Tho lisli were watched, and' note was taken of the time when they were first affected as well us of tho time of death, if deathensued. When nth were b'-ing studied which normally live in highly-aerated water, ""special means of agitation were adopted 10 kee'j tho water sufficiently well aerated." Tables are given showing the tesults of the tests, In© lust shows the effect of ammoniacal liquor anil it? ingredients. Free ammonia is proved to bo very deadly to fish. In the proportion of .1 pait to 1000 parts of water it killed' gudgeon in six minutes, and dace in 2.5 minutes. Some of the ammonium salts, such sulpho-cyanide, sulphate, sulphide, and carbonate are also noxious, though in a. less degree. Tho second tabic shows the effect of coal tar oils and their associated bodies. Phenol is the most deadly of them, ami a solution (.100 to 10C0 parts" of water) killed gudgeon and dace alike in 60 minutes. Some of ttie others, such as soluble creosote, were a Isc deadly, though to a loss extent. Another tabic shows tho effect on gudgeon and dace of '"aqueous extracts of coal tar obtained by vigorous agitation for 15 minutes." Six different kinds of tar (analysed in another table) were used, and of tlvse crude light coal tar (1 vol to 200 vols of water) was much the most deadriy, killing gudgeon and dace in 15 and 14 minutes respectively, while 'freed I '' light coal tar. containing no ammonia and only .01 grammes of phenolic bodies per litre. (1 vol to 20vols of water, diluted to 200), only killed them in 1140 and 360 minutes respectively. '"The outstanding feature of the results is . . . that the extracts of

crude tars are more deadly to fish than extracts of ' freed' tars of corresponding phcwolic .strength. Among Mr Butterfield's experiments was one devoted to the effect on fish life of water which has been in contact with agricultural fertilisers, nitrate of soda, sulphate of ammonia, lime, stable manure, etc. Gudgeon and dacewore unaffected by the fust, (1 part in 1000), wore killed by the second and' third in the same proportions, but not affected by thorn in the proportion of 0.1 part to 1000 parts. Natural drainage from stable manure, diluted till the yield of ammonia was equal to 0.2 part, killed gudgeon in 1440 minutes and dace in 210. These artilicial results ere, it is pointed out, more serious than any that would be likely to arise naturally, but they are of importance since ''the waterproofing of the read surface by means of tar and similar materials seemed likely to cause concentrated extracts of horse droppings than formerly to be washed from the road surface into streams." It has also been suspected for some time that fertilisers might have something to do with pollution troubles. Concentration of the washings might well follow heavy :»tid <~>>- tinuous rain. Ammonia and tar killed fish in the following order: Perch and trout, dueo and pope, tench, gudgeon, carp. Phenolic poisoning affected 1 grayling fust, then perch and trout together, and afterwards pike, pope, minnow, roach, gudgeon, dace, tench, carp; it killed as follows: perch on dtrout, minnow, pike, grayling, pope, roach, dace, gudgeon, tench, carp. This evidence as to the relative delrcacy of different fish is interesting, and that perch and trout should be killed' first is what one would have expected. far as fish life is concerned, ho concludes by saying that road surveyors may in all ordinary cases feel .safe in using only coal tar or a mixture of coal tar and earburelted water gas tar, which in either case: (1) is of not lower specific gravity at 15deg C. than 1.18; (2) contains not more than 1 per cent, of water or gas liquor, (he ammonia in which is equal to not more than 5 grains per gallon of tar; (3) contains not more than 1 per cent, of light oils; and (4) contains not mere than 3 per cent, by volume of crude tar acids. Jf cases occur whore tho washing* from tarred road's will not be diluted to at least 20 times their volume, before, or immediately on, entry to fishing waters, tho maximum limit, of water or liquor in the tar should lie reduced to 0.2 per cent ; of ammonia to 1 grain per gallon of tar; and of light oils to 0.8 per cent, (or 1 per cent, of distillate below 170dcg (-'. inclusive of wafer). As an eNtreme precaution in certain cases, a tar prepared from pitch and "dead" tar oils (i.e.. middle and heavy tar oils from which rlie phenols have been extracted) might be used, and when the market value of carbolic acid, etc., is high, tho cost of such a prepared tar should not be very much greater than that of an ordinary good "freed" coal tar.