The regional climate has significantly warmed with erratically declining annual rainfall and intensified downpour within a narrower span of monsoon months, which led to an increased trophic state (≈algae) in most inland waters. Freshwater clupeids vitally control the aquatic food chain by grazing on algae. Despite increasing food availability, IUCN Red List® revealed 16 freshwater clupeids with a decreasing population trend. We investigated one such species’ reproductive dependencies, Gudusia chapra (Indian river shad), in the lower Gangetic drainage (India) under a mixed context of climate change and overfishing. Monthly rainfall (≥ 60–100 mm) and water temperature (≥ 31–32 °C) are key breeding cues for females. The regional climate seems inclined to fulfill these through the significant part of the breeding season, and indeed the species has maintained consistent breeding phenology over 20 years. Other breeding thresholds relevant to fishing include size at first maturity (≥ 6.8 cm; reduced by ~ 25–36%) and pre-spawning girth (Girth_spawn50 ≥ 7 cm; first record). Girth_spawn50 is a proxy of the minimum mesh size requirement of fishing nets to allow safe passage of “gravid” females (+ 22% bulged abdomen) and breed. The operational fishing nets (3–10 cm mesh) probably have been indulged in indiscriminative fishing of gravid females for generations. Under a favorably changing climate and food availability, existing evidence suggests a fishery-induced evolution in regional females (to circumvent such mesh sizes) through earlier maturation/puberty at smaller sizes. It could be an early warning sign of population collapse (smaller females → lessening fecundity → fewer offspring). Overfishing seemed to be a bigger threat than climate change.

区域气候已显着变暖，在季风月份的狭窄范围内，年降水量异常减少，倾盆大雨加剧，这导致大多数内陆水域的营养状态增加（≈藻类）。淡水丘比特通过放牧藻类来生命地控制水生食物链。尽管粮食供应量增加，但IUCN RedList®揭示了16种淡水丘比特，其种群数量呈下降趋势。我们调查了一种这样的物种的生殖依赖性，古杜氏菌（印度河流域），在恒河下游（印度），气候变化和过度捕捞混合环境下。每月的降雨量（≥60–100 mm）和水温（≥31–32°C）是雌性的重要育种线索。区域气候似乎倾向于在整个繁殖季节的大部分时间里满足这些条件，实际上该物种在20年来一直保持着一致的繁殖物候。其他与捕捞有关的繁殖阈值包括第一次成熟时的大小（_≥6.8 cm；减少约25–36％）和产卵前的围长（围产卵_50≥7 cm；首次记录）。围_spawn50是最小的网眼尺寸要求的替代品，以允许“重度”雌性（+ 22％的膨出腹部）安全繁殖。可操作的渔网（3–10厘米目）可能世世代代都沉迷于妊娠雌性的随意捕捞。在有利的气候和粮食供应变化的情况下，现有证据表明，通过较小尺寸的较早成熟/青春期，渔业可诱发区域雌性的进化（以规避这种网眼大小）。这可能是人口崩溃的预警信号（雌性变小→繁殖力降低→后代减少）。过度捕捞似乎是比气候变化更大的威胁。