[New ethyl-m-aminobenzoate salts as temporary anesthesia agents in trout raising]

Various ethyl-m-aminobenzoate salts were synthesized to conduct biological tests on a total of 170 trouts (rainbow, siven and Balkan) with a view to establishing new agents for brief narcosis. Of these excellent effect manifested phosphate and hydrochloride, the latter even excelling the effect of the well known preparation MS-222 which is a salt of methane sulfonic acid. The tested concentrations of the substances ranged from 1:20 000 to 1:80 000 and the exposure length--from 10 to 30 min. The recommended working concentrations are from 1:40 000 to 1:60 000 narcosis setting on within a few minutes. Respiration of narcotized fish remains almost unchanged. The fish recover completely when put in running water. It is inferred that fish narcosis can be used for their temporary immobilization in case of mannual operations.