LGL Ecological Research Associates, Bryan, TX, USA.
Independent Researcher, Morehead City, NC, USA.
Proc Biol Sci. 2020 Jul 8;287(1930):20200220. doi: 10.1098/rspb.2020.0220. Epub 2020 Jul 1.
For decades, fisheries have been managed to limit the accidental capture of vulnerable species and many of these populations are now rebounding. While encouraging from a conservation perspective, as populations of protected species increase so will bycatch, triggering management actions that limit fishing. Here, we show that despite extensive regulations to limit sea turtle bycatch in a coastal gillnet fishery on the eastern United States, the catch per trip of Kemp's ridley has increased by more than 300% and green turtles by more than 650% (2001-2016). These bycatch rates closely track regional indices of turtle abundance, which are a function of increased reproductive output at distant nesting sites and the oceanic dispersal of juveniles to near shore habitats. The regulations imposed to help protect turtles have decreased fishing effort and harvest by more than 50%. Given uncertainty in the population status of sea turtles, however, simply removing protections is unwarranted. Stock-assessment models for sea turtles must be developed to determine what level of mortality can be sustained while balancing continued turtle population growth and fishing opportunity. Implementation of management targets should involve federal and state managers partnering with specific fisheries to develop bycatch reduction plans that are proportional to their impact on turtles.
几十年来,渔业管理一直致力于限制对脆弱物种的偶然捕捞,而许多这些种群现在正在恢复。从保护的角度来看,这是令人鼓舞的,因为受保护物种的数量增加,副渔获物也会增加,从而引发限制捕捞的管理行动。在这里,我们表明,尽管在美国东部的沿海水刺网渔业中采取了广泛的法规来限制海龟的副渔获物,但肯普氏丽龟(Kemp's ridley)的每次渔获量增加了 300%以上,绿海龟增加了 650%以上(2001-2016 年)。这些副渔获率与海龟丰度的区域指数密切相关,而海龟丰度的区域指数是由于在遥远的筑巢地繁殖产量增加,以及幼龟在海洋中的扩散到近岸栖息地。为帮助保护海龟而实施的规定已经减少了 50%以上的捕捞努力和收获。然而,鉴于海龟的种群状况存在不确定性,仅仅取消保护措施是没有道理的。必须为海龟制定种群评估模型,以确定在平衡海龟种群增长和捕捞机会的同时,可以承受多大程度的死亡率。管理目标的实施应涉及联邦和州管理人员与特定渔业合作,制定副渔获物减少计划,这些计划应与其对海龟的影响成比例。