EFFECTS OF DIET, STOCKING DENSITY, AND SPONGY SANDY BOTTOM ON GROWTH PERFORMANCE AND SURVIVAL RATE OF YOUTHFUL VENUS (Periglypta puerpera Linnaeus, 1771) LARVAE DURING THE BOTTOM - DRELLING STAGE

Abstract

This study was conducted to evaluate the effects of feed, stocking density, and bottom substrate on the growth and survival rate of Youthful venus (Periglypta puerpera) larvae during the bottom-dwelling stage, providing a scientific basis for improving the artificial nursing procedure of square clams. Experiments were conducted on feed (3 treatments), stocking density (4 treatments), and substrate (3 treatments). The monitored parameters included length growth and survival rate of larvae after 60 days of rearing. The results showed that bottom-dwelling larvae fed TA2 (a combination of four algal species: Nanochloropsis sp., Isochrysis sp., Chaetoceros sp., and Tetraselmis sp., mixed in the ratio of 1: 1: 1: 1) and reared at a stocking density of 300,000 individuals/m² achieved the highest survival rates of 4.80 ± 0.32% and 4.60 ± 0.22%, respectively, which were statistically significantly higher (p < 0.05) than the survival rates of bottom-dwelling larvae fed TA1 (a combination of three algal species: Nanochloropsis sp., Isochrysis sp., and Chaetoceros sp., mixed in the ratio of 1: 1: 1) and the survival rates of bottom-dwelling larvae reared at densities ranging from 450,000 to 750,000 individuals/m², respectively. The spongy sandy bottom significantly affected the length growth and survival rate of bottom-dwelling larvae, with the treatment without a spongy sandy bottom showing a higher survival rate compared to the treatment with a 3 cm spongy sandy bottom. The research results show that the selection of food, density and suitable bottom conditions plays an important role in improving the efficiency of rearing Youthful venus larvae during the bottom-dwelling stage.