Fish kill investigations are critical to understanding threats to aquatic ecosystems and can serve as a measure of environmental disruption as well as an early indicator of emerging disease. The goal of this study was to analyze historical data related to such events among wild fish populations in Minnesota in order to assess the quality and completeness of the data and potential trends in fish kills. After excluding events with incomplete data (e.g., in which the location was not reported), we analyzed 225 unique fish kills from 2003 to 2013 that were recorded in two Minnesota Department of Natural Resources databases. The most reported fish kills occurred during 2007 (n = 41) and during the month of June (n = 81) across all years. Centrarchid species were present in the most fish kills (138), followed by cyprinid and ictalurid species, which were present in 53 and 40 events, respectively. Environmental factors were the most common cause of death reported. Models of environmental factors revealed that the maximum nighttime land surface temperature was the most critical factor in fish mortality, followed by changes in primary productivity and human disturbances. During the course of this study, data gaps were identified, including underreporting, inconsistent investigation, and the lack of definitive diagnoses, making interpretation of our results challenging. Even so, understanding these historical trends and data gaps can be useful in generating hypotheses and advancing data collection systems for investigating future fish kills. Our study is a primer investigation of fish kills providing information on the plausible areas, seasons, and fish groups at risk that can guide active environmental monitoring and epidemiological surveillance of fishes.

中文翻译：

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鱼类死亡事件的回顾性和预测性调查

鱼类捕杀调查对于了解对水生生态系统的威胁至关重要，可以作为衡量环境破坏的指标以及新出现疾病的早期指标。本研究的目的是分析明尼苏达州野生鱼类种群中与此类事件相关的历史数据，以评估数据的质量和完整性以及鱼类死亡的潜在趋势。排除数据不完整的事件（例如，未报告位置的事件）后，我们分析了 2003 年至 2013 年间记录在两个明尼苏达州自然资源部数据库中的 225 次独特的鱼类死亡事件。报告最多的鱼类死亡发生在 2007 年（n = 41）和所有年份的 6 月份（n = 81）。Centrarchid 物种出现在大多数鱼类死亡中 (138)，其次是鲤科动物和 ictalurid 物种，分别出现在 53 个和 40 个事件中。环境因素是最常见的死亡原因。环境因素模型显示，夜间最高地表温度是鱼类死亡的最关键因素，其次是初级生产力的变化和人为干扰。在这项研究过程中，发现了数据差距，包括漏报、不一致的调查和缺乏明确的诊断，这使得我们对结果的解释具有挑战性。即便如此，了解这些历史趋势和数据差距对于产生假设和推进数据收集系统以调查未来的鱼类死亡是有用的。我们的研究是对鱼类死亡的初步调查，提供有关可能的区域、季节、