Abstract An at-sea experiment was undertaken to evaluate the performance of 150 shallow depth (5 m) prototype drifting fish-aggregating devices (DFADs) with rope appendages, compared to 150 standard depth (∼ 40 m) traditional design DFADs with purse-seine net appendages, in the equatorial eastern Pacific Ocean tuna purse-seine fishery, seeking a solution to reduce purse-seine fishing mortality on undesirable sizes of bigeye tuna. Following concurrent deployments of the two DFAD types along transects, the average daily drift speeds were significantly different but similar as were the drift trajectories among the two DFAD types. Based on evaluations of the time-series of acoustic data from the echo-sounder buoys attached to the shallow and standard depth DFADs, the average time before aggregation by non-tuna species was 15.3 d (range: 3.2–65.5) and 18.2 d (range: 1.1–101.2), respectively, and the average time before aggregation by tuna species was 62.2 d (range: 3.3–248.3) and 70.2 d (range: 1.5–270.5), respectively. Analyses of the catch per set data for tunas and non-tuna species, using generalized additive mixed models with Bayesian inference, indicated no significant differences in catch rates from sets on shallow and standard depth DFADs. There was a similar proportion of bigeye tuna in the catch for purse-seine sets on the shallow and standard depth DFADs.

中文翻译：

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赤道东太平洋金枪鱼围网渔业浅层原型与标准深度传统设计漂流集鱼装置的性能评估

摘要 进行了一项海上实验，以评估 150 个带有绳索附件的浅水 (5 m) 原型漂流集鱼装置 (DFAD) 的性能，与 150 个标准深度 (∼ 40 m) 的带围网的传统设计 DFAD 相比。赤道东太平洋金枪鱼围网渔业中的净附属物，寻求一种解决方案，以减少围网捕捞对不受欢迎的大眼金枪鱼的死亡率。在沿横断面同时部署两种 DFAD 类型后，平均每日漂移速度显着不同，但与两种 DFAD 类型之间的漂移轨迹相似。根据对连接到浅层和标准深度 DFAD 的测深仪浮标的声学数据时间序列的评估，非金枪鱼物种聚集前的平均时间为 15.3 天（范围：3.2-65。5) 和 18.2 d（范围：1.1-101.2），金枪鱼物种聚集前的平均时间分别为 62.2 d（范围：3.3-248.3）和 70.2 d（范围：1.5-270.5）。使用带贝叶斯推理的广义加性混合模型对金枪鱼和非金枪鱼物种的每组捕获数据进行分析，表明浅层和标准深度 DFAD 的组捕获率没有显着差异。在浅层和标准深度 DFAD 上围网捕捞的大眼金枪鱼比例相似。表明在浅层和标准深度 DFAD 上的捕捞率没有显着差异。在浅层和标准深度 DFAD 上围网捕捞的大眼金枪鱼比例相似。表明在浅层和标准深度 DFAD 上的捕捞率没有显着差异。在浅层和标准深度 DFAD 上围网捕捞的大眼金枪鱼比例相似。