THE EFFECTS OF PH ON THE DEVELOPMENT OF TENCH, TINCA-TINCA LARVAE

The influence of pH (4-11) upon larval development of tench, length an d weight increments, length-weight relationship and developmental anom alies and diseases was investigated. Larvae died during the first larv al developmental step at water pH 4 and 11. At pH 5, development was m oderately retarded, the growth rate was significantly retarded and the occurrence of developmental disorders was almost twice as high as tha t at the optimum pH (7-8). Development of the larvae was most rapid at pH 7, and these larvae had the lowest length-weight ratio. The critic al period of development lasted until the end of the third larval step . The total quantity of morphological and pathological disorders was 3 2.1 - 69.7%.