Department of Biology, Ichthyology Group of the Universidad de Antioquia, Universidad de Antioquia, Medellín, Antioquia, Colombia.
Postgraduate Program of Environment and Sustainable Technologies (PPGATS), Fronteira Sul University (UFFS), Cerro Largo, RS, Brazil.
PLoS One. 2023 Oct 19;18(10):e0291413. doi: 10.1371/journal.pone.0291413. eCollection 2023.
Spawning sites play a key role in the reproduction of fish allowing populations to endure over time. The Nechí River is an important spawning area for potamodromous fish species where one of the threats is dam construction. In order to determine the importance of the Nechí River as a spawning site in the Magdalena River basin, sampling was conducted during the low-water-to-high-water season transition period between 2018 and 2019 at seven sampling sites. The average density of ichthyoplankton was 42.4 ind.10m-3 (SD = 7.1). Of the individuals in the post-larval stage, seven migratory species were identified, and two additional taxa were identified to genus; Prochilodus magdalenae, Megaleporinus muyscorum, and Pseudoplatystoma magdaleniatum presented the greatest density. At the temporal level, the greatest density of larvae of potamodromous species was observed in the first high-water season of 2019 with a total of 5.7 ind.10m-3(SD = 1.044), of which the most representative at the seasonal level were the Cauca River, Magdalena River, and Nechí River before it flows into the Cauca River. There were significant differences in the frequency of embryos and vitelline larvae of the potamodromous species in the interaction of the sampling sites and high-water seasons, as well as with the density of post-larvae. The average drift distance of the spawning areas is roughly 52.1 km. A positive association was found between the volume of turbined water and the presence of ichthyoplankton in the Porce River site, after discharge from the Porce III Hydroelectric Plant. The Nechí River is an important spawning site and there seems to be an association between the increase in ichthyoplankton densities and the distance to the dam (Porce III) as long as there are floodplains along the course of the river.
产卵场在鱼类繁殖中起着关键作用，使种群能够随着时间的推移得以延续。内希河是洄游性鱼类的重要产卵场，其中一个威胁是水坝的建设。为了确定内希河作为马格达莱纳河流域产卵场的重要性，在 2018 年至 2019 年低水位到高水位季节过渡期，在七个采样点进行了采样。鲱鱼幼体的平均密度为 42.4 ind.10m-3（标准差=7.1）。在后期幼虫中，确定了七种洄游物种，另外两个分类单元确定到属；Pseudoplatystoma magdaleniatum、Prochilodus magdalenae 和 Megaleporinus muyscorum 表现出最大的密度。在时间水平上，2019 年第一个高水位季节观察到洄游性鱼类幼虫的最大密度为 5.7 ind.10m-3（标准差=1.044），其中在季节性水平上最具代表性的是考卡河、马格达莱纳河和内希河，在它流入考卡河之前。在采样点和高水位季节的相互作用以及后期幼虫的密度方面，洄游性鱼类胚胎和卵黄幼虫的频率存在显著差异。产卵区的平均漂流距离约为 52.1 公里。在波塞 III 水电站放水后，发现波塞河站点的涡轮水体积与鲱鱼幼体的存在呈正相关。内希河是一个重要的产卵场，只要河流沿线有洪泛区，鱼类幼体密度的增加似乎与大坝（波塞 III）的距离有关。
