Abstract Small-scale fisheries can greatly impact threatened marine fauna. Peru's small-scale elasmobranch gillnet fishery captures thousands of sharks and rays each year, and incidentally captures sea turtles, marine mammals and seabirds. We assessed the ability of a dedicated fisheries remote electronic monitoring (REM) camera to identify and quantify captures in this fishery by comparing its performance to on-board observer reports. Cameras were installed across five boats with a total of 228 fishing sets monitored. Of these, 169 sets also had on-board fisheries observers present. The cameras were shown to be an effective tool for identifying catch, with > 90% detection rates for 9 of 12 species of elasmobranchs caught. Detection rates of incidental catch were more variable (sea turtle = 50%; cetacean = 80%; pinniped = 100%). The ability to quantify target catch from camera imagery degraded for fish quantities exceeding 15 individuals. Cameras were more effective at quantifying rays than sharks for small catch quantities (x ≤ 15 fish), whereas size affected camera performance for large catches (x > 15 fish). Our study showed REM to be effective in detecting and quantifying elasmobranch target catch and pinniped bycatch in Peru's small-scale fishery, but not, without modification, in detecting and quantifying sea turtle and cetacean bycatch. We showed REM can provide a time- and cost-effective method to monitor target catch in small-scale fisheries and can be used to overcome some deficiencies in observer reports. With modifications to the camera specifications, we expect performance to improve for all target catch and bycatch species.

中文翻译：

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远程电子监测作为小型渔业船上观察员的潜在替代方案

摘要 小规模渔业可以极大地影响受威胁的海洋动物群。秘鲁的小型弹鳃刺网渔业每年捕获数以千计的鲨鱼和鳐鱼，并偶然捕获海龟、海洋哺乳动物和海鸟。我们通过将其性能与船上观察员报告进行比较，评估了专用渔业远程电子监控 (REM) 摄像机识别和量化该渔业捕获物的能力。摄像机安装在五艘船上，总共监测了 228 个渔具。其中，169 组还配备了船上渔业观察员。这些摄像机被证明是一种识别捕获量的有效工具，对捕获的 12 种弹鳃类动物中的 9 种具有 > 90% 的检测率。偶然捕获的检测率变化更大（海龟 = 50%；鲸目动物 = 80%；鳍足类动物 = 100%）。对于超过 15 条鱼的数量，从相机图像量化目标捕获量的能力会下降。对于少量捕获（x ​​≤ 15 条鱼），相机在量化光线方面比鲨鱼更有效，而尺寸会影响大捕获量（x > 15 条鱼）的相机性能。我们的研究表明，REM 可有效检测和量化秘鲁小规模渔业中的弹鳃目标捕捞量和鳍足类兼捕物，但未经修改，无法检测和量化海龟和鲸类兼捕物。我们展示了 REM 可以提供一种时间和成本效益高的方法来监测小规模渔业的目标捕获量，并且可以用来克服观察员报告中的一些缺陷。随着相机规格的修改，我们预计所有目标捕获和兼捕物种的性能都会提高。