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Show 22 MR. MORTON ALLPORT ON THE [Jan. 13, moss, charcoal, &c. from the gravel-beds ; and for some time afterwards the average death-rate was a mere fraction ; but it increased as the hatching approached. . - On the 4th of May, 1864, Mr. Ramsbottom had the high gratification of seeing the first Trout burst its egg in Tasmanian water, and on the following day the first Salmon. The ova continued to hatch until the 15th of June, 1864, by which time Mr. Ramsbottom (then appointed Superintendent at the ponds) estimated the number of young Salmon at about 3000, and of young Trout at about 50. There are two reasons for the vast difference between the estimated number of living ova and the number of hatched fish :-one, that a large percentage of the most healthy-looking ova turned out absolutely barren through defective impregnation ; another, that a large number of deaths occur at the very point of hatching, the embryo dying without being able to free itself from the egg. Early in August the perforated zinc guards at the lower ends of the breeding-boxes were removed and the Salmon-fry permitted to drop down with the stream into the shallows at the upper end of the large Salmon-pond, whence they gradually found their way to the pond itself. By the end of August several of the Trout (all of which, up to this time, had remained in the trough in which they were hatched) died, and many others showed symptoms of disease. As no cause could be traced for this mortality, a gravelly rill was constructed at the upper end of the clearing-pond, and the entrances to and exits from the whole were guarded with perforated zinc. The Trout were then transferred to the rill; and it was ascertained that so many had hidden away under the gravel that, instead of 50, close upon 300 young fish were counted. In the clearing-pond the young Trout continued to thrive, and grew amazingly, no deaths being observed. Amongst the Salmon the mortality was, up to this time, trifling, being confined to such few weak fish as were driven against the perforated zinc guards and had not strength to fight against the stream. On the 4th of October, 1864, a leak was discovered, by which a large run of water found its way from the Salmon-pond into the Plenty ; and, fearing lest the Salmon should have been escaping, the Superintendent placed a box in such a manner as to intercept any fish passing through. One was soon found in the box, and an attempt was unsuccessfully made to remedy the leak. From the 7th to the 25th of October a trench was cut across the place where the leak occurred, and the defective place puddled, and the leak ultimately stopped; but during these nineteen days 240 fry were captured which had passed through, and it is certain that a very large number had previously reached the Plenty. Till March 1865 everything continued to progress in a satisfactory manner at the ponds; the young fish, which had been at first supplied with boiled liver powdered fine, were now almost entirely fed on gentles, and up to the 10th of March exhibited all the appearance of vigorous health. From the 10th to the 15 th of March no less than forty parr died: all of them appeared plump, well-grown |