Fishery observers are prevalent actors in the global effort to reduce discards in fisheries, but there remains considerable uncertainty about how effective they are. We analyzed high-resolution logbook records of individual hauls ( n = 127 415) across five-and-a-half-years (2012–2018) for all of Greenland’s large-scale fisheries to determine if onboard fishery observers influence the mandatory reporting of discards. To do so, we used exact matching to compare reported discards for observed and unobserved hauls (each time a catch is recorded), thus controlling for systematic differences between monitored and unmonitored practices. After adjusting for variables that represent species caught, gear, vessel, owner, year, license, and location, we found that skippers systematically underreport discards when no observers are on board. Systematic underreporting was most pronounced in less valuable fisheries, in contrast to theoretical arguments in previous studies. The differences...

中文翻译：

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渔业观察员探讨北极渔业丢弃物

渔业观察员是全球减少渔业丢弃物的主要行动者，但其有效性仍存在很大不确定性。我们分析了格陵兰岛所有大型渔业历时五年半（2012-2018年）的单个捕捞活动（n = 127 415）的高分辨率航海日志记录，以确定船上渔业观察员是否会影响强制性报告。丢弃。为此，我们使用精确匹配对观察到的和未观察到的拖运（每次记录了捕获量）的报告丢弃物进行比较，从而控制了监测和未监测实践之间的系统差异。在调整了代表捕获的物种，渔具，船只，所有者，年份，许可证和位置的变量后，我们发现船长在没有观察员的情况下系统地低估了丢弃物。与以往研究中的理论论证相反，在价值较低的渔业中，系统性报告不足的现象最为明显。差异...