PHILOSOPHICAL INSTITUTE.

Press, Volume LIV, Issue 16309, 5 September 1918, Page 8

PHILOSOPHICAL INSTITUTE.

ADDRESS BY MR M. H. GODBY. A meeting of the Canterbury Phil# sophical Institute was held last night. Mr W. H. Skinner presiding over at attendance of about fifty. It was announced that Mr H. H. Allan, of Ashburton, and Mr A. Wells Newton, of Christchurch, had been elected members. Mr M. H. Godby read a paper or "The Evidence Afforded by Scales as tc the Age and Hate of Growth ol Mr explained that the study of fish scales was a comparatively new one, having been begun in 1899 bj a German scientist, who made observations on the scales of carp, the life history of which he knew, and showed that each year a mark of definite character appeared on the scale corresponding to the period of slow winter growth, Othor workers with other fish confirmed this observation, showing that the age, and oven the amount of annual growth, of various fish, including salmon and trout, might be determined by observation of the scale markings. A photo, of the scale of a four-yoar-old fish was tlirown on the screen, which showed the elliptical shape, the central point of origin of growth, and the concentric circuli, with the annual condensation or thickenings of these into bands, indicating the fasting winter period. Mr Godby said that his own observations were made chiefly from material procured through the assistance of the Canterbury Acclimatisation Society, whoso officials "tagged" various fish at spawning time, so that their development could be studied on recapture. In this way he had been able to find abundant confirmation of the accuracy of this method of calculation, of both ago and annual growth. Scales lost by accident (for they were not lost otherwise) were, he said, replaced by others of abnormal growth, wnich were useless for "scale reading." Observations of the rate of growth showed that •fish in the Selwyn and Lake Ellesmere grew in their first four or five years of life moro rapidly than those m Norwegian waters, but the latter fish ultimately grew faster, and attained greater length after seven or eight years. The maximum length of Selwyn fish apeared to be about 28 inches. Fish • from snow rivers, such as the Ashley, Waimakariri, and Rakaia, showed greater .growth in the third, fourth, _ and fifth years, than those from rain rivers, such as the Selwvn, Styx, and Opihi, this being apparently due to the migratorv habits of snowrivor fish. Lake Coleridge, into which fish were turned out in TB6B, had ever since been remarkable for the greaf size and rapid development of its fish, and one showed by its scale marks in the fifth year a growth of over 13 inches, but this was apparently abnormal. Mr Godby concluded by expressing his gratitude to Dr. Chilton for his assistance, and also to the •Acclimatisation Society. Mr Edgar Stead remarked on the vital economic importance of Mr Godby's studies, as bearing on the possibility of raising taarketablc -fish in our lakes and fivers as a commercial proposition. Ho also offered an explanation ef some of the abnormalities in the growth-rings shown by Mr Godby, suggesting that with the advent of the "silveries" in the rivers the trout made extra rapid growth, which received a che n k when this special food supply diminished thus producing an apparent "winter band." Several other' members spoko, also members of the Acclimatisation Society, who were present by invitation. It was remarked that an important feature of the paper was that such accurate scientific data should have been recorded in such a patient and careful manner by a non-profession scientific worker. * The question was askod as to whether the marks indicating a check in growth wore due to a natural period of hibernation, but Mr Godby seemed to think that it was duo to a period of voluntary starvation at or about spawning time. Dr. Chilton exhibited a fungus growth (Armil'aria mellea) discovered by Mr Evan Parry, Government Electrionl Engineer, ami Mr Dinnie, in wood props in the Otira Tunnel. This fungus nad proved to be the early stage of a well-known mushroom, and was interesting in its rapid growth— two feet or so in a day.