Impacts of extensive driftnet fishery and late 1990s climate regime shift on dominant epipelagic nekton in the Transition Region and Subtropical Frontal Zone: Implications for fishery management
Impacts of extensive driftnet fishery and late 1990s climate regime shift on dominant epipelagic nekton in the Transition Region and Subtropical Frontal Zone: Implications for fishery management
复制标题
DOI：
10.1016/j.pocean.2015.03.007
复制
发表时间：
2017
影响因子：
4.1
通讯作者：
T. Ichii;H. Nishikawa;H. Igarashi;H. Okamura;K. Mahapatra;M. Sakai;T. Wakabayashi;D. Inagake;Y. Okada
中科院分区：
文献类型：
--
作者：
T. Ichii;H. Nishikawa;H. Igarashi;H. Okamura;K. Mahapatra;M. Sakai;T. Wakabayashi;D. Inagake;Y. Okada
基于1979-2006年的漂网调查，我们调查了大规模的人为事件(公海漂网鱿鱼渔业)和自然事件(20世纪90年代末主要气候变化)对北太平洋中部过渡区域主要上层鱼类、鱿鱼和鲨鱼的影响。日本、韩国和台湾在1979-1992年期间以霓虹飞鱼为目标进行捕捞，导致作为该渔业副渔获物的目标物种和非目标物种(太平洋鲟鱼和幼年蓝鲨)的数量下降。结果发现，霓虹飞鱼的渔获量处于最大可持续产量(MSY)水平，蓝鲨幼鱼处于欠捕捞水平，而太平洋长鳍金枪鱼处于过度捕捞水平。太平洋Pomfret的MSY表明，该物种比以前认为的更容易被开发。为应对1990年代后期的制度转变，霓虹飞鱼和太平洋秋刀鱼分别在1999-2002年和1998-2002年由于其苗圃(分别是亚热带锋区和黑潮延伸分叉区)生产力下降而显示出低的种群水平。另一方面，在低和中等生产力状态下，由于其主要产卵/育苗场(过渡带叶绿素前沿)具有较高的生产力，因此在低和中等生产力状态下，其种群数量没有表现出下降的趋势，这与该区域的变化无关。因此，鱿鱼和秋刀鱼似乎比Pomfret更容易受到政权更迭的影响。我们讨论了对渔业和制度转变的特定物种反应对种群管理的影响。
We investigated the impacts of extensive anthropogenic (high seas driftnet squid fishery) and natural (late 1990s major climate regime shift) events on dominant epipelagic fish, squid, and shark in the central North Pacific Transition Region based on a driftnet survey covering the years 1979–2006. Fishing was conducted by Japan, Korea and Taiwan to target neon flying squid in the period 1979–1992, resulting in a decline in stocks of the target species and non-target species (Pacific pomfret and juvenile blue shark), which were by-catch of this fishery. The catch was found to be at the maximum sustainable yield (MSY) level for neon flying squid, the underfished level for juvenile blue shark, but the overfished level for Pacific pomfret. The MSY of Pacific pomfret indicated that this species is more susceptible to exploitation than previously considered. In response to the late 1990s regime shift, neon flying squid and Pacific saury showed low stock levels in 1999–2002 and 1998–2002, respectively, as a result of reduced productivity in their nursery grounds (the Subtropical Frontal Zone and Kuroshio Extension Bifurcation Region, respectively). On the other hand, Pacific pomfret showed no decreasing trend in stock during the low- and intermediate-productivity regimes because of the high productivity of their main spawning/nursery ground (Transition Zone Chlorophyll Front), which was independent of the regime shifts. Thus, squid and saury appear to be more susceptible to the regime shift than pomfret. We discuss the implications for stock management of the species-specific responses to the fishery and the regime shift.