To evaluate the effect of stocking density on pre-fattening growth and survival, Manila clam seeds from three different batches (B1, B2, and B3) were farmed in plastic net lanterns at two sites (western and northern) in Sacca degli Scardovari (Italy). Different stocking densities were compared, i.e. EXTRA (50,000 clams m⁻²), HIGH (30,000), and MEDIUM (20,000) for B1 and B2 clams; HIGH, MEDIUM, and LOW (10,000 clams m⁻²) for B3 clams. At the end of pre-fattening at the western site, the shell length decreased with increasing stocking density of both B1 (14.2 mm vs. 13.6 mm vs. 12.9 mm at HIGH vs. MEDIUM vs. EXTRA density; P < 0.001) and B2 (14.9 mm vs. 13.6 mm vs. 12.5 mm at MEDIUM vs. HIGH vs. EXTRA density; P < 0.001) clams. At the northern site, the shell length decreased in the following manner: MEDIUM to HIGH to EXTRA density for B1 clams (P < 0.001) and MEDIUM to EXTRA to HIGH density for B2 clams (P < 0.001). The same trend was recorded for B3 clams at both western (16.1 mm vs. 14.3 mm vs. 12.7 mm at LOW vs. MEDIUM vs. HIGH density; P < 0.001) and northern (15.6 mm vs. 13.9 mm vs. 13.2 mm; P < 0.001) sites. The stocking density did not affect the survival rate at the northern site and of the B3 clams, whereas the survival rate significantly decreased from MEDIUM and HIGH to EXTRA density for B1 (84.8 % and 85.4 % vs. 52.8 %; P < 0.05) and B2 (92.5 % and 87.6 % vs. 67.0 %; P < 0.01) clams at the western site where pre-fattening ended one week later than at the northern site. In the present conditions, clams in suspended lanterns reached the minimum sowing size (shell length 11 mm, weight 0.3 g) in 10 weeks. However, an increase in stocking density decreased clam growth and drastically increased mortality when water conditions became less favourable.

为了评估放养密度对繁殖前生长和存活的影响，将三个不同批次（B1，B2和B3）的马尼拉蛤c种子种植在意大利萨卡德格拉斯卡尔多瓦里（Sacca degli Scardovari）两个地点（西部和北部）的塑料网灯笼中。 ）。比较了不同的放养密度，即B1和B2蛤的EXTRA（50,000蛤m ^-2），HIGH（30,000）和MEDIUM（20,000）；高，中和低（10,000蛤m ^-2）用于B3蛤。在西部地区的预肥育结束时，壳长随B1的放养密度的增加而降低（高，中，超密度时，分别为14.2毫米，13.6毫米和12.9毫米； P <0.001）和B2 （中密度vs.高密度vs.额外密度时，分别为14.9毫米vs.13.6毫米vs.12.5毫米; P <0.001）。在北部站点，壳长以下列方式减小：B1蛤的中等至高至超高密度（P <0.001）和B2蛤的中等至超高至高密度（P <0.001）。在西部（16.1毫米对14.3毫米对12.7毫米，低对中对高密度； P <0.001）和北部（15.6毫米对13.9毫米对13.2毫米； B3蛤在西部（16.1毫米对14.3毫米对12.7毫米）和北北部（15.6毫米对13.9毫米对13.2毫米）都记录了相同的趋势。 P <0.001）位。种群密度不影响北部地区和B3蛤的成活率，而B1蛤的成活率从中，高到超高分别为B1（84.8％和85.4％vs. 52.8％; P <0.05）和B2（92.5％和87.6％vs. 67.0％; P <0.01）西部地区的加脂工作比北部地区晚了一周。在当前条件下，悬挂灯笼中的蛤c在10周内达到最小播种尺寸（壳长11毫米，重量0.3克）。但是，当水的条件变得不太有利时，种群密度的增加会降低蛤的生长并大大增加死亡率。悬挂灯笼中的蛤s在10周内达到最小播种尺寸（壳长11毫米，重量0.3克）。但是，当水的条件变得不太有利时，种群密度的增加会降低蛤的生长并大大增加死亡率。悬挂灯笼中的蛤s在10周内达到最小播种尺寸（壳长11毫米，重量0.3克）。但是，当水的条件变得不太有利时，种群密度的增加会降低蛤的生长并大大增加死亡率。