Identification of factors affecting the growth and survival of the settling Japanese flounder larvae, Paralichthys olivaceus
Identification of factors affecting the growth and survival of the settling Japanese flounder larvae, Paralichthys olivaceus
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DOI：
10.1016/s0044-8486(02)00531-8
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发表时间：
2003-03
期刊：
影响因子：
4.5
通讯作者：
Shuozeng Dou;R. Masuda;Masaru Tanaka;K. Tsukamoto
中科院分区：
文献类型：
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作者：
Shuozeng Dou;R. Masuda;Masaru Tanaka;K. Tsukamoto
进行了一系列实验来确定影响鲽鱼幼体牙鲆生长和存活的因素。孵化后24天（DAH）的沉降幼虫在10升实验池中饲养至40 DAH，并且在每个实验中改变以下两个因素作为控制因素：光照制度（24L：0D或12L：12D），猎物密度（1500、3000或5000卤虫l−1），庇护所（沙子或无沙子）和饲养密度（5， 10 条或 15 条鱼 l−1)。早期定居幼虫（24-35 DAH）的死亡率很少（低于总死亡率的 10%），不受上述因素的显着影响。相比之下，晚定居幼虫（36-40 DAH）的同类相食死亡率很高，这受到上述每个因素的显着影响。 10 条鱼 l−1 水平下的幼虫死亡率显着低于其他密度。当所有其他因素相同时，15 条鱼 l−1 水平的幼虫比 5 条鱼 l−1 水平的幼虫死亡率更高。 3000 和 5000 卤虫 l−1 处理下的幼虫存活率明显好于 1500 卤虫 l−1 处理下的幼虫，但两种较高密度之间的幼虫死亡率没有显着差异。当幼虫暴露在较长的光周期下时，在低猎物密度或没有沙子的情况下死亡率较高。低放养密度显着促进了沉降幼虫的生长。 5 和 15 条鱼 l−1 处理时的平均每日瞬时生长率（G）分别为 0.050 和 0.034，最终长度变异系数（CV）分别为 16.4 和 23.5。日瞬时生长率从1500只卤虫l−1的0.033显着增加到3000只和5000只卤虫l−1的0.041和0.045，但两种较高猎物密度之间的幼虫生长没有显着差异。这些发现表明，在 5-15 条鱼 l−1 的放养密度下，鲽鱼幼体生长和生存的最佳猎物密度约为 3000 条丰年虫 l−1。暴露于 24L 的幼虫比暴露于 12L 的幼虫 (G=0.037, CV=20.5) 生长增加 20% (G=0.046, CV=18.7)。如果有足够的食物，较长时间的光照可以显着改善幼虫的生长。沙基质对幼虫生长没有表现出显着影响，可能是因为幼虫在此阶段大部分时间都在水体中游泳或进食。
A series of experiments were conducted to identify the factors that affected the growth and survival of the settling flounder larvae Paralichthys olivaceus. Settling larvae 24 days after hatching (DAH) were reared in 10-l experimental tanks up to 40 DAH, and two of the following factors were changed as controlled factors in each experiment: light regime (24L:0D or 12L:12D), prey density (1500, 3000, or 5000 Artemia l−1), shelter (sand or no sand) and stocking density (5, 10, or 15 fish l−1). Early settling larvae (24–35 DAH) experienced little mortality (less than 10% of the overall mortality) that was not significantly affected by above factors. In contrast, late settling larvae (36–40 DAH) suffered high cannibalistic mortality, which was significantly influenced by each of the above factors. Larvae experienced significantly lower mortality at 10 fish l−1level than at other densities. Larvae at 15 fish l−1level had higher mortality than at 5 fish l−1when all other factors were identical. Larvae at 3000 and 5000 Artemia l−1treatments survived significantly better than at 1500 Artemia l−1, but no significant differences in larval mortality were found between the two higher densities. Larvae suffered higher mortality at low prey density or at the absence of sand when they were exposed to longer photoperiod. Low stocking density significantly improved the growth of the settling larvae. The average daily instantaneous growth rate (G) at 5 and 15 fish l−1treatments were 0.050 and 0.034, with the coefficient of variation (CV) in final length at 16.4 and 23.5, respectively. Daily instantaneous growth rate increased significantly from 0.033 in the 1500 Artemia l−1to 0.041 and 0.045 in the 3000 and 5000 Artemia l−1, respectively, but no significant difference in larval growth existed between the two higher prey densities. These findings suggested that the optimal prey density for growth and survival of the settling flounder larvae at a stocking density of 5–15 fish l−1was around 3000 Artemia l−1. Larvae that were exposed to 24L showed 20% increase in growth (G=0.046, CV=18.7) than those exposed to 12L (G=0.037, CV=20.5). Longer exposure to light significantly improved larval growth, provided sufficient food was available. Sand substrate did not show significant effects on larval growth, possibly because the larvae spent most of the time swimming or feeding in the water column during this stage.