On the Marking of the Small-sweet-fish, Plecoglossus altivelis TEMMINCK et SCHLEGEL, in the Lake Ikeda : A Preliminary Report, Especcially on the Selection of Marking Methods

Marking experiments of the small-sweet-fish were executed in the Lake Ikeda in order to find the most effective method, and the following were comfirmed as the favourabe factors, such as 1) As the recovery rate of the tagging in Atkins method is better than that in the fin-clipping method provided that the experiments are carried out during the fishing season ; at least in the fishing season (February~May), Atkins method should be adapted as the most effective one, while cares should be paid in decling the losing rate of the tag. The tagging mortality rate and the tag-losing rate were favourable when the square-shaped vinyl plate (4mm by 4mm) were attached to the fish body at the front of the dorsal fin through the back with the small-saurel-hook. 2) In the season excepting the fishing one, the fin-clipping method is to be regarded as the most effective one ; but it has the defect that it takes much time in checking and recovering the marked fish. 3) It seems to be most profitable for us to make us SANDOZ : 0.6%, one of the most effective anesthetices prevailing now as the drug accelerating the marking process