FISH CULTURE

Southland Times, Issue 21091, 24 May 1930, Page 8

FISH CULTURE

RESEARCH DIRECTOR’S VISIT.

AN INSTRUCTIVE LECTURE

‘Tor a long time it has been felt by persons interested in fish culture down here tljat our supplies have been deteriorating,” remarked Mr J. Robertson, president of tne Southland Acclimatization Society, when introducing Professor Percival, the lecturer for the evening, to a largely attended gathering of anglers assembled in the Mary Elizabeth tearooms. “Up north, research authories are delving into this question and gathering all the statistical data possible. At the recent conference o£ Acclimatization Societies it was decided to establish a Research Board to thoroughly investigate the matter and the Canterbury delegates recommended that the professor should be associated with the board in the capacity of Director of Research. I am sure that, after you have heard this evening’s lecture by the professor, who, as you are aware, is Professor of Biology at Canterbury College, you will agree that the Canterbury delegates were thoroughly justified in their recommendation. Our local society had some problems which we referred to the board and I should like to express our thanks to it for sending the professor to Southland so promptly in order to investigate the problems on the spot.” The subject chosen bj’ the lecturer was “The Economics of the Stream,” and his extremely interesting survey of the question was closelj' follower! throughout. “I am not a fisherman for I have caught only one in my life,” the professor prefaced his address. “Fishing is only incidental to my line. That is, perhaps, a good thing because I have been able to tackle the problem on a purely scientific basis.” The speaker, continuing, emphasized that in the investigating of a stream the fish was but one of a series of questions demanding study. The rate at which the current flowed, due to the fall of the land, bore a striking significance. In certain cases the current moved slowly and particles were not all carried to the sea. That aspect was an important one for many fish depended for their 'livelihood on the organisms on the bottom of the stream. There was ttyus a distinction to be drawn between rivers with unstable beds and those streams with stable bottoms. The professor exhaustively dealt with the substratum, explaining the different positions in which eggs were laid. Continuing, he referred to the varying amount of oxygen in different, streams. A turbulent stream possessed the maximum oxygen which fosterer! the growth of the fish, while standing water depleted their strength. The plants ’in the stream were also a means of increasing the oxygen supply. Pollution was explained in detail, slides being shown to illustrate the lecturer’s remarks. It had been established by experiment that it was possible to pour into a stream waste organic matter which might- cause tremendous damage for a time, but the river would recover at a later period. Conditions were foul at the outset, but normal later. Unsuitable water had a prejudicial effect upon the stocking of the young fry and upon the placings bf the eggs. After touching upon various other aspects of his subject, the professor drew comparisons between and showed slides illustrating the growth of fish in the local streams.

After answering certain questions asked, the lecturer, on the motion of Mr Eustace Russell, was accorded a very hearty vote of thfanks for his instructive and brisk lecture. In the' course of his remarks, Mr Russell paid a tribute to the work of the board and said that although the investigation of the problem would undoubtedly be a lengthy one, the professor could rest assured ’ the acclimatization societies, and through them the anglers, would give every aaaptance in the matter.