Chaetognaths are ubiquitous in the marine environment and are among the most abundant carnivorous plankton. Nevertheless, characterization of physiological parameters remains limited largely due to the difficulty in obtaining the data from pelagic chaetognaths in laboratory studies. This study therefore aimed to determine the feeding and growth rates of Zonosagitta nagae under laboratory rearing condition. A total of 54 field-collected chaetognaths with maturity Stage I and II ranging from 5 to 12 mm in body length collected in June, August and October were individually incubated at 20–22°C with excess copepod prey and growth parameters were obtained from 26 individuals that survived ~10–46 days. For Z. nagae, ingestion and growth rates increased with body dry weight, and both parameters were significantly related, indicating that gross growth efficiency was ~47%. Specific ingestion rates ranged from 0.03 to 0.43 d⁻¹ and tended to decrease with an increase of size of the chaetognaths. Individual specific growth rate varied widely in small-sized individuals (~6 mm), ranging from −0.103 to 0.135, but became relatively constant (~0.032) with increasing size. Overall the study results suggest that Z. nagae is characterized by high gross growth efficiency, which is in striking contrast with previously studied inshore species.

中文翻译：

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在实验室饲养的中上层石斑鱼（Zonosagitta nagae）的饲养和生长效率

棘齿藻在海洋环境中无处不在，是最丰富的食肉性浮游生物之一。然而，由于在实验室研究中难以从上层鱼类获得数据，因此生理参数的表征仍然受到很大限制。因此，本研究旨在确定在实验室饲养条件下长鳍金线鱼的摄食和生长速率。分别在6月，8月和10月收集的54个野外捕食的象嘴虫（阶段I和II，体长在5至12毫米之间）分别在20–22°C下与过量的pe足类猎物一起孵化，并从26个获得了生长参数存活约10-46天的个体。对于z。nagae，摄食和生长速率随体重增加而增加，并且两个参数均显着相关，表明总生长效率约为47％。比摄入率在0.03至0.43 d ^-1范围内，并且随着the鱼的大小增加而趋于降低。小型个体（〜6 mm）的个体比生长率差异很大，范围从-0.103至0.135，但随着大小的增加而变得相对恒定（〜0.032）。总体而言，研究结果表明，纳卡藻的总生长效率高，这与以前研究的近海物种形成鲜明对比。