FRESHWATER RESEARCH

Press, Volume LXXI, Issue 21448, 13 April 1935, Page 10

FRESHWATER RESEARCH

N'.Z. COMMITTEE'S WORK ,\ QUESTION OF VALUE >By E. PERCEVAL*

The New Zealand Freshwater ReSearch Committee commenced its activities early in. 1030. its work 'being the investigation ox the well-being of trout and other acclimatised fishes. The conference of Acclimatisation Societies, held in September, 1929, decided on the setting up of a research body, even though a warning was -"wen that no beneficial results might accrue, and that it was inadvisable to look for returns inside about 10 years. It is clear, then, that acclimatisation societies, through their delegates, were prepared to finance a search for knowledge whether or not the knowledge #o gamed would be of any value. The question of the "value" of the work of the committee has recently teen discussed in newspaper correspondence columns, and it has been decided by at least one writer that the Committee has produced nothing of "value" to the angler. ••Value" is a term the meaning of depends upon the attitude of the valuer to the tiling to be valued. V/e snay take it that the angler looks for en addition in knowledge which may Enable him to increase the value to fiim of fishing, by increasing the number of fish, or average weight, or aesthetic enjoyment of sport, or an understanding of the relations which „fexist between him and the fish. I know that many anglers have appreciated the increase in knowledge which the committee has been able to provide about the anatomy of fish, about the management of water and numerous other matters. When the conference met in 1919. it "Was generally agreed that there was a «erious lack of knowledge and understanding about the most elementary aspects of fishery management. The system hitherto followed was pructic- > ally that laid down by the commercial pisciculturists of Britain and the United States about 70 years ago. There was a feeling that ail was not well with fishing here, and many and interesting were the explanations advanced of the apparent depreciation in the quality of trout fishing in various waters. The Research Committee published in 193 L-!, in the Fisheries Bulletin No. 5, an explanation which, ■although strenuously opposed at first. has met with general approval; the explanation is that, commonly, increased fishing intensity tends to lower the average age and average weight of fish. Estimation of Fish Food In the course of the last five years it has been my business to travel the country for the purpose of examining rivers or lakes. Part of this work was concerned with an estimation of the amount of potential fish food, arising out of a contention that, the starvation of fish was taking place. Anglers. from time to time, accompanied mc, and all have been astonished at the amount of feed present. They have usually confessed to having, for the first time, realised that a river held anything other than fish. In general there has been settled the argument which raged about the need for introducing new food organisms from overseas to replenish allegedly impoverished rivers. The committee has been at pains to accumulate a body of knowledge relating to the growth, rate, and age of fish in different waters throughout the country. This has led to an extensive and intensive survey of fish populations, resulting in the examination of thousands of samples from different parts. The survey was rendertad •necessary by the comparative absence of data referring to growth and age , in the earlier days of acclimatisation. So much had been said about decline in growth rate, without proper foundation in fact, that it has been necessary to collect records for present and ■future use. The examination of these data has been the full-time work of one man and his assistant for several years. The results of these examinations ..have already yielded valuable inforifmation about growth-rate, age composition, spawning frequency, and age .of maturity, and provide information which was not dreamed of by the '.average angler. The systematic collection of records has recently enabled the tracing, through a succession of years, of the fish born in a particular year, thus giving an idea of the relation between the catch and a particular year class. Such work has always been considered valuable in, and forms and integral part of marine fishery (investigation, in that it shows what is actually taking place with regard to each season's hatch. Regeneration of Stocks The special study of the fish as a means of regeneration of stocks has occupied about three years, during which time a large amount of new knowledge has been derived. It has been said by some to be impossible, by others to be too costly, to discover what happens to salmon and trout eggs when naturally shed. The Research Committee's biologist, working in the stream, has found the work neither impossible nor costly. He has required only intelligence and tenacity of purpose to carry out work which previously and elsewhere has been merely talked about. This work arose out of the need to find what part natural regeneration of stocks played in providing fish for the angler. It has generally been accepted that natural spawning has been insignificant in its effect upon the stock. We know now, after patient and arduous toil, that natural spawning, in particular places, can provide an amount of fry which makes artificial stocking look like a candle flame 1n brilliant sunlight. The practical application of this knowledge is the next step. A further method of discovering the •fleet of natural regeneration is to examine catches to determine how far natural stocks can be distinguished from artificial, in an angler's catch, so enabling the statement in percentage of what proportion of a catch was provided by human agency. Work is proceeding towards this end. Other work, with a similar end in view, is being initiated where artificial stocking ceases for a specific period, after which, when a number of years have elapsed, the stock is re-examined and differences noted. This needs the active co-operation of societies'and recently one has agreed to act. The results should assist the license-holder to appreciate better how far his money is being spent effectively. Committee's Programme '£he programme of work offered to end accepted by the conference of last .year has been adversely criticised recently by at least one man who. as a delegate, endorsed it. The criticism has shown itself to be ill-informed nbout the purpose of the work and the principles underlying research methods. The critic took the attitude that certain efforts were not worth while, that some problems were insoluble, and that others were fully understood. Such a position is pitiful in these days of rapid scientific progress when nature is being brought into subjection at an increasing rate. A critic of this kind probably drives a jßiotor-car, owns a wireless set, enjoys Hiedlcal and other health-maintaining facilities, and many other amenities which a few years ago were either eonsidered out of reach, or not worth While, or were never contemplated. Criticism is very often based on misconception or ignorance. For instance, the critic said that the trout yields jjßpproQtimately 1000 eggs for every PWind of fish, although the seventieth

annual report of the North Canterbury Aclimatisation Society states that in 1932 3210 females averaged 1119 eggs each, and in 1933 the 3040 females ""averaged 1419 eggs. The yield in 1934 was about the same as that in 1933. The fish stripped in the Selwyn river range from 21b to 51b, with an average of about 41b. When such a critic proceeds to lay down the law which shall determine the and outcome of scientific research, without first having considered the available evidence, he runs the risk of becoming a laughing stock. To research is to find out._ and it is usual to proceed along certain lines, namely, to determine the facts, to construct a theory, and to test the theory. The results may or may not be of value to anyone but the investigator. Some results have no apparent value for decades. How long was it before Faraday's dynamo became "useful"? Even Mr Gladstone is said ,to have been amused at this "toy"! My contention is that the research committee has done work of value in that it has provided knowledge where none previously existed, that it has added to knowledge which did previously exist, and that it has materially assisted the thinking angler to understand better the relations between himself and the fish and between the fish and the' environment. It has done this in a relatively short time, in spite of short funds and few workers. The workers have had to be trained and much of the equipment made by hand. Because the work is not yet complete is no justification for damning the worker; if it were, then we might comfortably sink back into barbarism.