EXPERIMENT WITH SALMON

Press, Volume LXIX, Issue 21024, 28 November 1933, Page 7

EXPERIMENT WITH SALMON

WORK IN ENGLAND AN ENCLOSED RIVER (FHOSI OUB own COBHEStOKDEST.) LONDON, October 13. A special correspondent of the "Morning Post" reports that an experiment of far-reaching importance to salmon fisheries throughout Great Britain will be started soon on the Hampshire Avon by the Zoological Department of Southampton University College. It will be the first scientific attempt to discover whether man can aid the breeding' of salmon more efficiently than nature. If he can, the annual catch of salmon in British rivers may be enormously increased without the need of a subsidy. If he cannot, all the money spent on salmon hatcheries may have been thrown away. • Scheme of Experiments. A Royal Commission recommended a scheme of public experiments in connexion with salmon breeding as far back as .1902. A scheme was framed by the Inter-Departmental Committee on artificial propagation last year, only to be abandoned owing to the need for national economy. Now the Southampton University College has taken the matter up, as a result of investigations in the Avon, which it is carrying out for the Hampshire Rivers Board of Conservators. It has been found that the Avon is stocked with far more food for salmon than is ever likely to be eaten. Unless more salmon eggs can be "made" to turn into fry than nature is allowing, this wealth of food will be wasted. The test, therefore, is, "Can hatcheries do better than na+'-re —and how much better?" Counting the Fry. The percentage of salmon fry artificially raised from given quantities of salmon eggs in hatcheries is known. The experiment must show what percentage—greater or smaller than the hatcheries—is raised by nature in the living river—and a new river is being made for the purpose. It will be a "carrier" on an ideal

site on the Avon offered to the college for the experiments by an enthusiast A "carrier" is a waterway from one stretch of the river to another, closed at each end by sluicegates, and designed to flood watermeadows. Mr J. Barry and his assistants from the college are turning this channel into a little Avon for salmon pairs to mate in late this autumn. A bed of gravel, ideal for spawning, will be laid down, and the water turned in at the right volume and speed. Method of Work. Then two pairs of salmon will be netted in the Avon itself, just before mating, hastily measured, so that the number of eggs the females will lay, can be calculated, and turned into the "carrier." When the mating is complete they will be let out through the lower sluice-gates, and fry-proof meshes will be spread across to prevent the young fry from escaping when they hatch. Much later the water will be turned ofi, and a census of the fry taken. To allow for changing factors, the experiment will be repeated for several years, when nature' -, best average for hatching fry can be compared with that artificially raised. On this and accompanying experiments the future yields of salmon in the Avon, and British rivers in general, may depend.