Scales were used for the determination of age with back-calculation of length. The oldest fish was VII + years old. Back-calculation did not exhibit Lee's phenomenon. The most rapid growth occurred in summer at water temperatures over 25" C. The growth in weight was c. 331 g year-' after IV vears of life. Growth was well described by von Bertalanffy . 1 2 2 (1-0'*5)]. The length-weight relationship followed the cube law (6 = 3.0601) K , ranged from 0.74 to 1.18 with a mean value of 1.0. Spawning occurred in January, fecundity was 74 509 with a mean of 1 157 eggs g-' body weight. Mean diameter of eggs was 1071 (pm). A developed ovary had ova of two sizes, immature oocytes and mature ova. The fish is a carnivorous feeder.

R Re ec ce ei iv ve ed d 1 16 6 O Oc ct to ob be er r 2 20 00 08 8, , A Ac cc ce ep pt te ed d 2 28 8 D De ec ce em mb be er r 2 20 00 08 8) ) K Ke ey yw wo or rd ds s : :C Ca ad di im mu um m, ,H He em ma at to op pi ie et ti ic c, ,N Ne ec cr ro os si is s. . ABSTRACTDestruction of spleen and kidney components in C. idella started on the 17 th day in specimens subjected to 20 µg•L -1 Cd . The spleen was actually destructed after 73 days of exposure to 60 µg•L -1 Cd , where the two pulps can not be distinguished clearly, as the splenic blood vessels contained less blood cells . The kidney showed a complete destruction and the hematopoietic tissue lacked a distinguishable border whereas the necrosis covered large area after 60 days at 60 µg•L -1 Cd .The degree of destruction was lineary proportional to concentration of toxicant and period of exposure although the period was somewhat more effective .It was concluded that the histological alterations in spleen and kidney could be used as an indicator for water pollution with cadmium and for fish health as well .

No abstract

No abstract

No abstract