Facultad de Ciencias, Universidad Católica de la Santísima Concepción, Concepción, Chile.
Centro de Investigación en Biodiversidad y Ambientes Sustentables (CIBAS), Universidad Católica de La Santísima Concepción, Concepción, Chile.
Sci Rep. 2022 Feb 24;12(1):3164. doi: 10.1038/s41598-022-06936-8.
Longitudinal movement plays fundamental role in habitat colonization and population establishment of many riverine fish species. Movement patterns of amphidromous fish species at fine-scales that would allow characterizing the direction of movement and factors associated with the establishment of specific life-history strategies (resident or amphidromous) in rivers are still poorly understood. We assess fine-scale longitudinal movement variability patterns of facultative amphidromous fish species Galaxias maculatus in order to unfold its life-history variation and associated recruitment habitats. Specifically, we analyzed multi-elemental composition along core to edge transects in ear-bones (otoliths) of each fish using recursive partitions that divides the transect along signal discontinuities. Fine-scale movement assessment in five free-flowing river systems allowed us to identify movement direction and potential recruitment habitats. As such, resident recruitment of G. maculatus in freshwater (71%) and estuarine (24%) habitats was more frequent than amphidromous recruitment (5%), and was linked to availability of slow-flowing lotic or lentic habitats that produce or retain small-bodied prey consumed by their larvae. We postulate that life-history variation and successful recruitment of facultative amphidromous fish such as G. maculatus in river systems is driven by availability of suitable recruitment habitats and natural hydrologic connectivity that allows fish movement to these habitats.
纵向运动在许多洄游鱼类的栖息地定殖和种群建立中起着至关重要的作用。对于在河流中能够描述鱼类运动方向以及与特定生活史策略（定居或洄游）建立相关的因素的，具有精细尺度的溯河鱼类的运动模式仍然知之甚少。我们评估了兼性溯河鱼类马加斯加斜齿鳊 Galaxias maculatus 的精细尺度纵向运动变化模式，以揭示其生活史变化及其相关的洄游生境。具体来说，我们使用递归分区沿着耳骨（耳石）中的核心到边缘的横切分析了多种元素组成，该分区沿着信号不连续将横切划分为多个部分。在五个自由流动的河流系统中进行的精细运动评估使我们能够确定运动方向和潜在的洄游生境。因此，马加斯加斜齿鳊在淡水（71%）和河口（24%）生境中的定居式洄游比溯河洄游（5%）更为频繁，并且与存在缓慢流动的流水或静水栖息地有关，这些栖息地产生或保留其幼鱼所消耗的小体型猎物。我们假设，像马加斯加斜齿鳊这样的兼性溯河鱼类的生活史变化和成功的洄游是由合适的洄游生境的可用性和自然的水文连通性驱动的，这些生境和连通性允许鱼类洄游到这些生境。
