Partial migration, whereby a population comprises multiple behavioural phenotypes that each have varying tendencies to migrate, is common among many animals. Determining the mechanisms by which these phenotypes are maintained is important for understanding their roles in population structure and stability. The aim here was to test for the temporal and spatial consistency of migratory phenotypes in a common bream Abramis brama (‘bream’) population, and then determine their social preferences and extent of mixing across three successive annual spawning periods. The study applied passive acoustic telemetry to track the movements of bream in the River Bure system of the Norfolk Broads, a lowland wetland comprising highly connected riverine and lacustrine habitats. Analyses revealed that individual migratory phenotype was highly consistent across the 3 years, but this was not predicted by fish sex or length at tagging. During the annual spawning periods, network analyses identified off-channel areas visited by both resident and migrant fish that, in non-spawning periods, were relatively independent in their space use. Within these sites, the co-occurrence of bream was non-random, with individuals forming more preferred associations than expected by chance. These associations were not strongly predicted by similarity in fish length, sex or behavioural phenotype, indicating that the resident and migrant phenotypes mixed during their annual spawning periods. The results suggested these different phenotypes, with spatially distinct resource use in non-spawning periods, comprised a single population, with this having important implications for the management of this wetland resource.

在许多动物中，局部迁移是一种常见现象，即种群包含多种行为表型，每种行为表型都有不同的迁移趋势。确定维持这些表型的机制对于理解它们在种群结构和稳定性中的作用很重要。这里的目的是测试常见aAbramis brama中迁徙表型的时间和空间一致性。（“鲷鱼”）种群，然后确定他们的社会偏好以及在三个连续的年度产卵期中的混合程度。这项研究应用了无源声学遥测技术来追踪诺福克阔地（Norfolk Broads）的河B系统中的am运动。分析表明，个体迁移表型在过去三年中高度一致，但这不能通过鱼类性别或标记时长来预测。在年度产卵期，网络分析确定了居民和迁徙鱼类走访的离岸区域，在非产卵期，它们的空间使用相对独立。在这些地点中，of的共生是非随机的，个体形成的偶然联系比偶然所期望的要多。鱼类长度，性别或行为表型的相似性并不能强烈预测这些关联，这表明居民和外来表型在其每年产卵期混合在一起。结果表明，这些不同的表型，在非产卵期具有空间上不同的资源利用，包括一个单一的种群，这对于这种湿地资源的管理具有重要的意义。