EFFECTS OF SALINITY AND TEMPERATURE ON EGGS AND YOLK-SAC LARVAE OF THE GREENBACK FLOUNDER (RHOMBOSOLEA-TAPIRINA GUNTHER, 1862)

The greenback flounder (Rhombosolea tapirina) is considered to have po tential as an aquaculture species in southern Australia. Experiments w ere conducted to determine the optimal salinity for fertilisation and buoyancy of eggs, the optimal temperature and salinity combination for incubation of eggs, and the optimal temperature for yolk absorption. Experiments were carried out in 25 and 200 mi beakers and 3 1 containe rs. Optimal fertilisation rates occurred at salinities of 35-45 parts per thousand and eggs were buoyant at salinities above 28 parts per th ousand. The optimal temperature for egg incubation was approximately 1 2 degrees C and salinity had no effect if maintained between 15 and 45 parts per thousand. Yolk absorption appeared to be most efficient at 15 degrees C as this temperature resulted in the largest larvae at com plete yolk absorption and the fastest growth rate. First feeding occur red at the end of yolk absorption but before the oil droplet was absor bed.