TROUT VERSUS WHITEBAIT.

Hokitika Guardian, 31 May 1927, Page 4

TROUT VERSUS WHITEBAIT.

THE HISTORY OF THE WHITEBAIT (By I). HOPE, Curator, Fisheries Department. Christchurch). About fifteen years ago .1 heard so many opinions expressed as to what our whitebait (Galarias attenuatus) really wore, that [ procured some live whitebait and kept them in captivity in a small pond under natural conditions. and proved, to my own satisfaction that they are the young of the .Maori “liiuugu.” and also that their growth is extremely rapid. As this controversy has again arisen I have made the experiment this season, and procured early running whitebait on the 17th August, placed them in a small pond under natural conditions, kept a specimen as whitebait, and then took a specimen at intervals of three weeks to note their growth up to twelve weeks. I Those familiar with the immense I runs of whitebait which took place forty years ago cannot fail to notice i the gradual failure which has taken I place up to the present time. This cause is due to the increase in population and the increased demand for whitebait as a table delicacy, with the result that the stock is being depleted iby over-fishing. They are a very valI uahle asset as a food supply, and nni less steps re taken by the Alarine Department to conserve them it is only a question of time when they will he exterminated. At present there is not even a, defined season, they arc taken from the time thev make their lust appearane until they cease running, i and few in comparison, are allowed to I escape up stream to return again in I the autumn as adults “Inangas” to I the sea, to perpetuate their species. I There is also another view of the j matter which should he of interest to Acclimatisation Societies, more especi ially in the South Island, the value of [ the “Inanga” as a Brown trout food, I the food which has made , our Brown trout famous the world over. In the early days the whitebait entered all of our rivers in the early spring in countless millions, penetrated to the very source of all main streams and tributaries growing rapidlv into the adult stage during the process until every pool, backwater and ditch was peopled with myriads of “Inanga” from four to six inches in length, which provided an unlimited supply of food for the trout of the very quality which induced rapid growth, and it is not surprising that our trout attained dimensions and numbers undreamed of in the parent stock. In the late autumn the “Tnanga” returned again to the sea to spawn. In our Canterbury snow rivers the decrease of the “Inanga” has had a very marked effect oil the size and number of our trout up stream in recent years, and the only part at present where sport can he obtained is at their mouth’s, where there is an abundant supply of food in the shape of Silveries (Retropinna richardsonii) which enter the rivers in the spring for the purpose of spawning, but do not ascend above the influence of the tide. .Viter spawning they return again to the sea and the trout follow them; thus our Brown trout are now practically sea trout, spending the major portion of their lives in the sea itself, and only entering the river with the Silveries on their way to spawn.

From their respective habits, the “Inanga” was the more valuable trout food of the two, as they induced the trout to follow them upstream and remain upstream all the summer, and good fishing could la? obtained at any part of their course. But with the disappearance of the “Inanga’’ there has been a corresponding decrease in the size and number of our trout. The Government, through the Tourist Department spend large sums each year advertising New Zealand to attract tourists for our fishing and. scenic beauties and at the same time totally neglect the very cause which made at least our Brown trout fishing, world famous. Brown trout are fish feeders by nature, and cannibals by in-

struct. as witness specimens of cannibalism. in I'i.v one month old, a'>d j : it]co if a yearling would have any dillieulty in swallowing whitebait. AX KXPKKT OPINION.

]>;;ar Sir —Vonr letter of 3Uth ultima came to hand this morning. On act mint of my term of office with the Department expiring on the 30th April, I cannot reply to your letter officially, hut unofficially I he;; to make the following short remarks. With regal'd to the effect of the introduction of trout int > whitebait rivers, i: would seem La he an impossibility to say t.i what extent the iutroducti m m l>; nit may effect the run of whitebait. f ! here is no doubt hut laat. trout will feed largely on whitebait while they are running but as to how this mav effect the supplv of these little fish WHICH COME IN FROM Til 10 SKA in any one river, would seem to he a difficult ipiestioii to aus-

Titis is the lirxl time 1 have known of whitebait li-herim ii approaching an Ac limatisatioo <':eiely in this way. ,S nne time ago the Southland S. eteiy w rote I i me asking that the Department should slop whitebait netting i:\ t::o rivcis in district on t.’io grounds that. ih» netters reduced the Mijfply of v. liitehait and consequently reduced the Kiipply of feed for trout in the. rivers. (Signed) 1... F. AISOX. a/ArJ7.

AX OFFICIAL OPINION. Sir You ask for mv opinion as to whether the trout in the Hokitika were responsible lor the decrease in the whitebait catch. Before one can give a satisfactory reply to that question it is necessary to have a comprehensive knowledge of the feeding habits and abundance of inanga and whitebait ever a long succession of years together with an idea of the effect of other factors which are helpful or adverse to the well-being of this indigenous species. I nlortuliately the necessary information about matters is not available aiul without it any opinion must necessarily he based on a certain amount of guesswork.

Thei* is of course no getting away front flic tact that trout do cat whitebait and necessarily, everything that eats whitebait and everyone who catches whitebait is thereby decreasing the stock. Nature allows for a certain degree of mortality in each generation and the problem of conserving the stock of whitoibait turns upon that degree not being exceeded. II the trout i.i the river exacted an excessive toll upon the whitebait one would have expected the decrease in the whitebait runs to show itself when trout were most abundant in the Hokitika. I understand that trout were far more abundant several years ago than they are now. Whether whitebait were less abundant then than ol recent years is a question about which ] have no information.

Local observers are in a better position to judne but it seems to me doubtful whether anyone is actually sufficiently well provided with data from observations, made year alter year with the necessary thoroughness and recorded with the necessary precision, of the various factors which enter into the problem. It is not a new problem, but your Satiety has raised it from an aspect contrary to the one that is usually taken. Other Acclimatisation Societies have held the view that the whitebait should ho protected for the sake of the trout. They prefer that the white bait and inanga should be transformed into trout flesh, which has the additional advantage of providing healthy sport us well as food. The object of acclimatisation authorities should he to aim at maintaining a fair balance between the two and while it is obvious that one. cannot have the POSSIBLE MAXIMUM of both eater and eaten at the same time ; it must be remembered that the trout is only one just as the fishermen is only one of several factors that are inimical to the whitebait species.

It must be admitted that there >.< regrettable lack of precise information on <>U these matters and until that is available we shall always be at a disadvantage in dealing with problems connected with the rational conservation of both introduced and indigenous fishes.

A. E. HEFFORD. Chief Inspector of Fisheries