Matsuzaki Shin-Ichiro S, Fukaya Keiichi, Mabuchi Kohji, Kikko Takeshi, Takamura Noriko
Biodiversity Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.
Lake Biwa Branch Office, National Institute for Environmental Studies, 5-34 Yanagasaki, Otsu, Shiga, 520-0022, Japan.
Oecologia. 2025 Jul 2;207(7):121. doi: 10.1007/s00442-025-05762-9.
Multiple stressors can threaten the resources of inland fisheries, but responses to these stressors may differ among fish species. We used a long-term fishery dataset to quantify the CPUE trajectories of eight cyprinid taxa in the south basin of Lake Biwa that have been stressed by lakeshore development, artificial water-level regulation, exotic fish species, and climate change. A Bayesian state-space model revealed that the CPUEs of all eight taxa substantially declined from 1966 to 2022. For Opsariichthys uncirostris, Ischikauia steenackeri, Sarcocheilichthys spp., Cyprinus carpio, and Carassius spp., the average population growth rates decreased from 1976 to 1991, when lakeshore development occurred and largemouth bass populations increased dramatically. For the three remaining taxa (Zacco platypus, Gnathopogon caerulescens, and Squalidus spp.), the average population growth rates decreased from 1992 to 2022, when new water-level regulations were implemented and bluegill populations increased substantially. The former five taxa exhibited longer maximum body length and life span, later maturation, and higher fecundity than the latter three taxa. This suggests that life-history traits may determine how species respond to different stressors. Unlike the effects of these three abrupt stressors, those of climate, a gradual stressor, were negative for seven taxa, although not statistically significant. We also found that the population growth rates of Gnathopogon caerulescens and Ischikauia steenackeri increased recently after implementation of restoration measures (fishing moratorium and stocking of paddy-reared/captive-bred individuals). Our results suggest that cumulative anthropogenic stressors depleted the resource of cyprinids but that the outcome of current restoration measures may be positive.
多种压力源会威胁内陆渔业资源，但不同鱼类对这些压力源的反应可能存在差异。我们利用一个长期渔业数据集，对琵琶湖南部流域受湖岸开发、人工水位调控、外来鱼类物种和气候变化影响的8个鲤科类群的单位捕捞努力量渔获量（CPUE）轨迹进行了量化。贝叶斯状态空间模型显示，从1966年到2022年，所有8个类群的CPUE都大幅下降。对于吻鮈、斯氏高原鳅、鱊属鱼类、鲤鱼和鲫属鱼类，1976年至1991年期间平均种群增长率下降，当时湖岸开发出现，大口黑鲈种群急剧增加。对于其余三个类群（宽鳍鱲、青眼鳟和麦穗鱼属鱼类），平均种群增长率在1992年至2022年期间下降；当时实施了新的水位调控措施，蓝鳃太阳鱼种群大幅增加。前五个类群比后三个类群表现出更长的最大体长和寿命、更晚的成熟时间以及更高的繁殖力。这表明生活史特征可能决定物种对不同压力源的反应方式。与这三种突发压力源的影响不同，气候这一渐变压力源对七个类群产生了负面影响，尽管在统计学上不显著。我们还发现，在实施恢复措施（禁渔和投放稻田养殖/人工繁殖个体）后，青眼鳟和斯氏高原鳅的种群增长率最近有所上升。我们的研究结果表明，累积的人为压力源耗尽了鲤科鱼类资源，但当前恢复措施的结果可能是积极的。
