Effects of stocking densities on growth of the Pacific white shrimp (Litopenaeus vannamei) in earthen ponds

摘要

The effects of stocking density and physicochemical water characteristics on the growth, sur- vival, and production of the Pacific white shrimp, Litopenaeus vannamei, were assessed in six 500±72.5 m2 earthen ponds during two culture seasons: autumn-winter (20 weeks) and spring- summer (14 weeks). Stocking densities were 50, 60, and 70 shrimp/m2. Water turnover was approximately 15% per day. Aeration was supplied by a 3.5 hp air blower. Mean growth during the autumn-winter did not differ significantly among the stocking densities with final weights of 12.77, 12.72, and 12.40 g and yields of 3,609, 5,093, and 5,618 kg/ha at 50, 60, and 70 shrimp/m2, respectively. In contrast, there were statistically significant differences in mean growth and final yields during the spring-summer. Final mean weights were 18.63, 13.46, and 11.86 g and yields were 7,243, 7,307, and 8,011 kg/ha at 50, 60, and 70 shrimp/m2, respective- ly. Low water temperatures during the winter affected production. Better performance was recorded at higher spring-summer temperatures (≥23°C). Larger shrimp were associated with lower stocking density while higher stocking density produced slightly higher yields. For best per- formance, dissolved oxygen should be maintained above 4 mg/l.