The foraging activity of large-bodied benthivorous fish has been suggested to be of key importance for maintaining shallow lakes in a turbid state. since especially the spring ecosystem dynamics determines the successive state of shallow lakes, such impact could depend on seasonality in benthivore activity patterns. However, we do not yet know to what extent the activity of large-bodied benthivorous fish affects lake turbidity across the year. In order to investigate seasonal dynamics in bream activity and its impact on water turbidity under natural conditions, bream daily activity was studied in a small (39 ha) shallow Danish lake using passive biotelemetry technology, i.e. a modified Passive Integrated Transponder (PIT)-tag antenna system. We tracked the activity of 448 benthivorous bream over a period of four years (2012 to 2016) and during the same period wind conditions, water turbidity and temperature was measured. Results showed a clear relationship between bream activity and water turbidity at water temperature below 15°C indicating that winter season activity of benthivorous bream may play an important role for maintaining lake ecosystems in a turbid state. Also wind speed and wind direction affected water turbidity, suggesting that wind induced resuspension can be important even in small shallow lakes. This is to our knowledge the first full-scale study under natural conditions to describe how bream activity influence lake turbidity on a day-to-day basis. our findings also add a seasonal component to previous findings by showing that benthivorous feeding bream have the potential to increase water turbidity also in the winter season and thereby, ultimately, impact ecosystem functioning within shallow lakes. Corresponding author: ck@aqua.dtu.dk

中文翻译：

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不同季节条件下浅湖鳊（Abramis brama）活动与水浊度的关系

大型底栖鱼类的觅食活动被认为对于保持浅湖处于混浊状态至关重要。由于春季生态系统动态尤其决定了浅湖的连续状态，因此这种影响可能取决于底栖动物活动模式的季节性。然而，我们尚不清楚大型底栖鱼类的活动在多大程度上影响了全年的湖泊浊度。为了研究鲷鱼活动的季节性动态及其在自然条件下对水浊度的影响，使用被动生物遥测技术，即改良的被动集成转发器 (PIT) 标签，在一个小型（39 公顷）的丹麦浅湖中研究了鲷鱼的日常活动天线系统。我们在四年期间（2012 年至 2016 年）跟踪了 448 条底栖鲷鱼的活动，并在同一时期测量了风况、水浊度和温度。结果表明，鳊鱼活动与水温低于 15°C 的水浊度之间存在明显关系，表明底食性鳊的冬季活动可能对维持湖泊生态系统处于混浊状态发挥重要作用。风速和风向也会影响水的浊度，这表明即使在小型浅湖中，风引起的再悬浮也很重要。据我们所知，这是第一次在自然条件下进行全面研究，以描述鲷鱼的日常活动如何影响湖泊浊度。我们的研究结果还为之前的研究结果增加了季节性成分，因为表明底栖鲷鱼在冬季也有可能增加水的浊度，从而最终影响浅湖内的生态系统功能。通讯作者: ck@aqua.dtu.dk