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首页> 外文期刊>Fisheries Research >Changes in fishing power and fishing strategies driven by new technologies: The case of tropical tuna purse seiners in the eastern Atlantic Ocean
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Changes in fishing power and fishing strategies driven by new technologies: The case of tropical tuna purse seiners in the eastern Atlantic Ocean

机译：新技术驱动的捕捞能力和捕鱼策略的变化：大西洋东部的热带金枪鱼围网渔船案例

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Technological advancements can influence both the fishing power of a fleet and the fishing strategies it employs. To investigate these potential linkages, we examined almost three decades of data (1981-2008) from French tropical tuna purse seiners operating in the eastern Atlantic Ocean. Applying a sequence of statistical methods at different temporal and spatial scales, we analyzed two indicators of fishing power (sets per boat-day on fish aggregating devices (FADs) and sets per boat-day on free-swimming schools) each of which represent a distinct fishing mode. Our results show that the increasing modernization of this fleet has led to increases in both fishing power and the available number of fishing strategies to choose from. A key output of this analysis was the breakdown of fishing power time series (for each fishing mode) into separate periods of continuous years during which catchability was assumed to be constant, thus identifying regime shifts. This partitioning allowed us to identify when key changes occurred in the fishery. Changes in FAD-associated fishing were mostly driven by the introduction of radio beacons (early 1990s) which lead to an increase in fishing effort and an expansion of fishing grounds (direct effect) and the implementation of time-area management measures which resulted in a fragmentation of the traditional fishing grounds in the 2000s (indirect effect). During the same period, fishing on free-swimming schools also increased despite the biomass of stocks decreasing and fishing grounds remaining unchanged. This suggests these increases were driven by improvements in fish detection technology (e.g., bird radars, sonar). These identified increases are not entirely unexpected: indeed it is widely recognized that fishing power in the purse seine tuna fishery has increased over time. However, these increases do not necessarily occur linearly. Thus, understanding how fishing power is changing over time (such as determining when regime shifts occur) is critical to improving the CPUE standardization procedure in tropical tuna purse seine fisheries
机译：技术进步会影响船队的捕捞能力及其采用的捕捞策略。为了研究这些潜在的联系，我们检查了近三十年（1981-2008年）来自在大西洋东部操作的法国热带金枪鱼围网渔船的数据。应用一系列在不同时空尺度上的统计方法，我们分析了捕捞能力的两个指标（鱼类聚集设备（FAD）上每船日的设置和自由泳学校中每船日的设置），每个指标均表示独特的捕鱼模式。我们的结果表明，该船队日益现代化，导致捕鱼能力和可供选择的捕鱼策略数量增加。该分析的主要输出是将捕捞能力时间序列（针对每种捕捞模式）分解为连续的不同年份，在此期间假定可捕性是恒定的，从而确定政权转移。这种划分使我们能够确定渔业中何时发生了关键变化。与FAD有关的捕捞发生变化的主要原因是无线电信标的引入（1990年代初），这导致捕捞努力的增加和渔场的扩大（直接影响），以及时区管理措施的实施，导致了2000年代传统渔场的破碎化（间接影响）。在同一时期，尽管种群生物量减少且渔场保持不变，但自由游泳学校的捕捞活动也有所增加。这表明这些增加是由鱼类检测技术（例如，鸟雷达，声纳）的改进推动的。这些确定的增长并非完全出乎意料：确实，人们普遍认识到围网金枪鱼渔业的捕捞能力随着时间的推移而增加。但是，这些增加不一定是线性发生的。因此，了解捕捞能力如何随时间变化（例如确定何时发生政权转移）对于改善热带金枪鱼围网渔业中的CPUE标准化程序至关重要。

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