Data from: Response of Prochilodus nigricans to flood pulse variation in the central Amazon

The influence of the flood pulse on fish populations has been posited, but infrequently tested or quantified. Here, we tested the effect of habitat on population size, using Prochilodus nigricans as a case study species. Floodplain habitat was based on the littoral zone area occupied by P. nigricans to feed. The magnitude of this habitat in each hydrological year, the moving littoral (ML), was expressed as the sum of daily littoral areas during the advancing flood pulse, using satellite-based passive microwave data. Annual population size was estimated by age-class, using a dynamic age-structured model (MULTIFAN-CL) based on catches, effort, and fish length frequencies from the Manaus-based fishery over 12.75 years. The principal null hypothesis was that ML, using three lag times, had no effect on population size of a single age class of P. nigricans. The population size at 29 months of age was positively related (P=0.00030) to floodplain habitat (ML) earlier in the same year, when the fish were 21-27 months old. The result implies a density-dependent relationship for the population with respect to its feeding habitat. Potential mechanisms governed by flood pulse variation and habitat quality for this and other species utilizing floodplain habitats are discussed.洪水脉冲（flood pulse）对鱼类种群的影响虽已被提出假说，但相关验证与量化研究却鲜有开展。本研究以黑扁脂鲤（Prochilodus nigricans）为案例物种，探究生境对种群规模的影响。洪泛平原生境以黑扁脂鲤的摄食沿岸带面积为基准进行界定。该生境在每个水文年的规模被称为移动沿岸带（moving littoral, ML），其计算方式为基于卫星被动微波数据，统计洪水脉冲推进期间的每日沿岸带面积之和。本研究依托马瑙斯地区12.75年以上的渔业捕捞量、捕捞努力量以及鱼类体长频率数据，采用动态年龄结构模型（MULTIFAN-CL）按年龄组估算年度种群规模。本研究的核心原假设为：采用三种滞后时间的移动沿岸带（ML）对黑扁脂鲤单一年龄组的种群规模无显著影响。结果显示，当黑扁脂鲤处于21至27月龄时，其29月龄的种群规模与同年早期的洪泛平原生境（ML）呈显著正相关关系（P=0.00030）。该结果表明该种群的种群规模与其摄食生境之间存在密度依赖关系。本研究还探讨了由洪水脉冲变化与生境质量驱动的、针对该物种及其他依赖洪泛平原生境物种的潜在作用机制。