O. G. Dely szerk.: Vertebrata Hungarica 7/1-2. (Budapest, 1965)

Tóth, J. ; Rácz, B.: A new method of marking fish with a plastic (PVC) opercular tag 1-8. o.

Pricking carefully with the sharpened end of thee tweezers between the operculum and the praeoperculum, an aperture of 5-6 mm width is made for the insertion of the tag. Into this cut, one end of the thickened affixing wing of the tag is introduced, then pushed below the praeoperculum. The other end of the wing is then taken by the pincers and, folding it slightly, pushed into the same aperture. The wing of the tag will straighten out under the praeoperculum, and thus fix the mark to the fish /fig.

2/. The fish-marking process, discussed above, had been evolved in 1964 by multiple series of tests. Experiments were made in aquaria and fisheries , and the tag was used also in freshwater work. The experiences gained in the tests can be summarized as follows

. The marking process meets all requirements outlined in the introduction. The process is simple, it can be over in seconds, and it causes no severe injuries. The affixing wings, settling under the praeoperculum, effect no deformations or lesions even in later times. The tags lasted well for half a year also in the tests mad in the pondlets. Owing to the flexibility of the foil, t^e tag will not get entangled either in nets or among the aquatic plants. Some tags fell out only on the selecting table - hence outside of water - but this fault could be corrected by the thickening of the affixing wing. The text and the serial number of the tag remained easily readable even after half a year; nor did it get wet. By experimenting with carps of diverse ages and sizes, it could be established that the tag is applicable for the marking of every carp over a body-length of 10 cm. 3 • Experiments in fisheries have been made in the Kiskonda lakes of the State Farm Alsóleperd, by the cordial support of DR.P.CSIGO, agronomist. We express our gratitude for his cooperation also in this place.