Abstract The catch pattern of the exotic Common Carp (Cyprinus carpio) and their relationship with water quality along with maturity status of fishes were assessed during 2017-2019 to understand overall establishment and impact of the species in Buxar stretch of River Ganga in West Bihar, India. A total of 64 fish species were recorded including two exotic fishes (C. carpio and Oreochromis niloticus) from the river stretch during the study period. The annual production data depicted Cyprinus carpio to be the most dominating fish species encountered from the study area sharing 57.07% (by weight) during the period 2017-19. Calculated average ‘Invasion coefficient index (Ix)’of 0.25 in entire three-year study period revealed that the invasion has moderately impacted the indigenous fish diversity. Landing of Indian Major Carp (IMC) indicated severe decline (76.4 - 95.6%) in comparison to the catch data recorded earlier from Buxar. Data generated on sex structure of Common Carp indicated that the overall sex ratio showed positive recruitment within the smaller size range of 282-307 mm and thus avails a competitive breeding advantage over other carp fishes. Gut content of Common Carp from the stretch observed major share of phytoplankton (81.04%) and zooplankton (17.18%) and thus there are significant dietary overlap of Common Carp with other valuable species. The stretch has been impacted with anthropogenic loading as identified through significantly higher water specific conductivity (580 µScm-1), Biochemical Oxygen Demand (3 mgl-1), etc. in drastically reduced water discharge regime. Among different water parameters, river flow, Biochemical Oxygen Demand and Total Phosphate showed positive whereas specific conductivity showed negative correlation with Common Carp seasonal abundance. Future conservation management measures may be formulated keeping in view of the identified factors through the present study for reducing the impending risks of the invasive fish species in Buxar stretch of River Ganga.

中文翻译：

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印度恒河布克萨河段外来鲤（鲤鱼）的建立及其对本地鱼类多样性的影响

摘要 在 2017-2019 年间评估了外来鲤鱼 (Cyprinus carpio) 的捕捞模式及其与水质以及鱼类成熟度的关系，以了解该物种在西比哈尔邦恒河 Buxar 河段的总体建立和影响，印度。在研究期间，共记录了 64 种鱼类，包括两种外来鱼类（C. carpio 和 Oreochromis niloticus）。年产量数据显示，鲤鱼是研究区域遇到的最主要的鱼类，在 2017-19 年期间占 57.07%（按重量计）。在整个三年研究期间计算的平均“入侵系数指数 (Ix)”为 0.25，表明入侵对本地鱼类多样性产生了适度的影响。与之前从 Buxar 记录的捕获数据相比，印度主要鲤鱼 (IMC) 的上岸量显示严重下降 (76.4 - 95.6%)。鲤鱼性别结构的数据表明，总体性别比在 282-307 毫米的较小尺寸范围内表现出正向补充，因此比其他鲤鱼具有竞争性育种优势。从拉伸观察到鲤鱼的肠道含量主要是浮游植物（81.04%）和浮游动物（17.18%），因此鲤鱼与其他有价值物种的饮食有显着的重叠。拉伸受到人为负荷的影响，通过显着更高的水比电导率 (580 µScm-1)、生化需氧量 (3 mgl-1) 等在显着减少的排水状态下确定。在不同的水参数中，河流流量，生化需氧量和总磷酸盐呈正相关，而电导率与鲤鱼季节性丰度呈负相关。考虑到通过本研究确定的因素，可以制定未来的保护管理措施，以降低恒河布克萨河段入侵鱼类即将面临的风险。