Wildlife Conservation Society, Marine Program, Bronx, NY 10460, U.S.A.
Wildlife Conservation Society, Coral Reef Conservation Project, P.O. Box 99470, Mombasa, Kenya.
Conserv Biol. 2018 Feb;32(1):159-170. doi: 10.1111/cobi.12980. Epub 2017 Nov 8.
Reducing the capture of small fish, discarded fish, and bycatch is a primary concern of fisheries managers who propose to maintain high yields, species diversity, and ecosystem functions. Modified fishing gear is one of the primary ways to reduce by-catch and capture of small fish. The outcomes of gear modification may depend on competition among fishers using other similar resources and other gears in the same fishing grounds and the subsequent adoption or abandonment of modified gears by fishers. We evaluated adoption of modified gear, catch size, catch per unit effort (CPUE), yield, and fisher incomes in a coral reef fishery in which a 3-cm escape gap was introduced into traditional traps. There were 26.1 (SD 4.9) fishers who used the experimental landing sites and 228(SD 15.7) fishers who used the control landing sites annually over 7 years. The size of fish increased by 10.6% in the modified traps, but the catch of smaller fish increased by 11.2% among the other gears. There was no change in the overall CPUE, yields, or per area incomes; rather, yield benefits were redistributed in favor of the unmodified gears. For example, estimated incomes of fishers who adopted the modified traps remained unchanged but increased for net and spear fishers. Fishers using escape-gap traps had a high proportion of income from larger fish, which may have led to a perception of benefits, high status, and no abandonment of the modified traps. The commensal rather than competitive outcome may explain the continued use of escape-gap traps 3 years after their introduction. Trap fishers showed an interest in negotiating other management improvements, such as increased mesh sizes for nets, which could ultimately catalyze community-level decisions and restrictions that could increase their profits.
减少小鱼、弃鱼和兼捕是渔业管理者的主要关注点，他们旨在维持高产量、物种多样性和生态系统功能。改进渔具是减少兼捕和小鱼捕获的主要方法之一。渔具改进的结果可能取决于使用其他类似资源和同一渔场内其他渔具的渔民之间的竞争，以及渔民对改进渔具的采用或放弃。我们评估了在引入传统陷阱 3 厘米逃生间隙后，珊瑚礁渔业中改进渔具的采用、渔获物大小、单位努力渔获量（CPUE）、产量和渔民收入。在 7 年内，每年有 26.1 名（SD 4.9）渔民使用实验登陆点，228 名（SD 15.7）渔民使用对照登陆点。改良陷阱中的鱼体尺寸增加了 10.6%，但其他渔具中的小鱼捕获量增加了 11.2%。CPUE、产量或单位面积收入没有总体变化；相反，产量效益重新分配，有利于未改进的渔具。例如，采用改良陷阱的渔民的估计收入保持不变，但网和矛渔民的收入增加。使用逃生间隙陷阱的渔民收入中有很大一部分来自较大的鱼，这可能导致他们认为有收益、地位高，并且不会放弃改进后的陷阱。共生而非竞争的结果可能解释了在引入逃生间隙陷阱 3 年后，它们仍在继续使用。陷阱渔民对协商其他管理改进表现出兴趣，例如增加网的网目尺寸，这最终可能会促成社区层面的决策和限制，从而提高他们的利润。
