Common carp (Cyprinus carpio) is an invasive fish species in North America and around the world. Through their feeding and spawning they contribute to the deterioration of wetland habitats. Exclusion structures are a frequently used management option for limiting their negative impacts. While habitat responses to common carp exclusion have been reported, little is known about impacts of exclusion structure operation on native fish assemblages. Here we describe a common carp exclusion project on a large freshwater coastal wetland, Delta Marsh, in south-central Manitoba, Canada. Most fish species, including common carp, overwinter in Lake Manitoba and migrate each spring to feed and spawn in the marsh. Exclusion structures with removeable screens were installed on connecting channels between the lake and marsh and were deemed the best management option to exclude common carp from the marsh. In this paper we contrast relative abundance and mean size of large-bodied fish species between pre- (three years) and post- (six years) exclusion periods, as well as inside and outside the common carp exclusion zone. In addition, we monitored fish migration into the marsh to evaluate initial management recommendations. Using a combination of delayed exclusion screen placement and 70 mm screen openings, we were able to reduce the number of large common carp present in the marsh with minimal impacts on the native fish assemblage. We also provide suggested changes to the timing of screen placement to increase common carp exclusion.

鲤鱼（Cyprinus carpio）是北美和世界各地的入侵鱼类。它们的进食和产卵导致了湿地栖息地的恶化。排除结构是一种经常使用的管理选项，用于限制其负面影响。虽然栖息地对鲤鱼排斥的反应已有报道，但人们对排斥结构运作对本地鱼类群落的影响知之甚少。在这里，我们描述了加拿大马尼托巴省中南部大型淡水沿海湿地三角洲沼泽的鲤鱼排除项目。大多数鱼类，包括鲤鱼，在马尼托巴湖越冬，每年春天迁徙到沼泽地觅食和产卵。在湖泊和沼泽之间的连接通道上安装了带有可移动屏障的排斥结构，被认为是将鲤鱼排除在沼泽之外的最佳管理选择。在本文中，我们对比了禁区前（三年）和禁区后（六年）以及鲤鱼禁区内外大型鱼类的相对丰度和平均大小。此外，我们还监测了鱼类向沼泽的洄游，以评估初步的管理建议。通过结合延迟排除筛网放置和 70 毫米筛网开口，我们能够减少沼泽中存在的大型鲤鱼的数量，同时对本地鱼类群落的影响最小。我们还提供了对屏幕放置时间的建议更改，以增加鲤鱼的排除。