中文摘要：

多种中上层鱼类趋于在漂流物体下方聚集，人们由此发明了漂流人工集鱼装置（FAD）来吸引热带金枪鱼类．FAD同时也能吸引其他非目标鱼种，如纺锤御，但它们被FAD聚集的原因至今仍不清楚．本研究利用中西太平洋金枪鱼围网渔业科学观察员收集的渔业生物学数据，评估了纺锤御聚集在FAD下方的潜在动机．结果表明：漂流物下的纺锤御样本又长范围为30．0～90．6cm，优势又长组为60．0—80．0cm，占到总体的76．3％，说明漂流物下的纺锤蜥以体型较大的个体为主；纺锤蛳个体的50％性成熟体长为65．7cm，漂流物下纺锤蛳以性成熟个体为主；样本的胃含物中发现常见小型随附鱼种，如细鳞圆够、长鳍舵、六带够、鲣鱼以及大眼金枪鱼和黄鳍金枪鱼的幼鱼，表明聚集于漂流物下的纺锤御捕食其他的随附种类．纺锤缅成鱼作为一种大洋性的捕食者，觅食是其游向漂流物最可能的动机之一，“饵料供应”假说和“休息点”假说可用于解释纺锤脚的聚集原因．

英文摘要：

Many pelagic species tend to aggregate under drifting tloatmg objects, ires nas leu to the development of drifting fish aggregation devices （ FADs ） to attract the tropical tunas for the tuna purse seine fishery. However, FADs can also attract other non-targeting small pelagic species such as rainbow runner Elagatis bipinnulata, although it is still unclear why those species can be attrac- ted and aggregated under an FAD. Using the fishery biological data collected in the Western and Central Pacific Ocean by the scientific observers on board Chinese tuna purse seine fishing vessels, we evaluated the potential motivations for rainbow runner to aggregate under drifting objects. This study indicated 1 ） Fork length of rainbow runner ranged from 30.0 to 90.6 cm, with the dominant fork lengths of 60.0 to 80.0 cm, accounting for 76.3 % of the total sampled fish, suggesting large rainbow runner dominating around the drifting objects; 2） Size （fork length） of E. bipinnulata at 50% maturity was 65.7 cm, and mature individuals were dominant under the FADs ; and 3 ） Some commonly observed small fish species, such as Decapterus macarellus, Kyphosus cinerascens, Car- anx sexfasciatus, Katsuwonus pelamis and the juveniles of Thunnus obesus and Thunnus albacares, were found in the stomach of rainbow runner, which suggested that rainbow runner under FAD preyed on other associated small pelagic species. As an oceanic predator associated with drifting ob- jects, feeding is perhaps one of the most possible motivations for adult E. bipinnulata to aggregate under the FAD. Both the ＂concentration of food supply＂ hypothesis and the ＂comfortability stipula-tion＂ hypothesis can be used to explain why E. bipinnulata aggregate under drifting floating ob- jects.