The study presents new information on the population characteristics of two river snail species, Viviparus viviparus (Linnaeus, 1758) and V. contectus (Millet, 1813), in the water bodies of Ukraine in 2007–2018. The analyzed features include data of the species distribution, numbers and biomass, age and sex ratio population structure, fertility, growth and production. Ecological factors (flow rate, temperature, the concentration of oxygen, pH, organic matter) that limit the distribution of two Viviparidae species in varying biotopes were identified. Recently, the frequency of occurrence, and the number and biomass of populations V. viviparus and V. contectus have been observed to decrease. The probable reason is the declining environmental conditions induced by the climatic changes and anthropogenic pressure. In waters of Ukraine, maximum age is five years for V. viviparus mollusks and six years for V. contectus. High anthropogenic pressure disturbs age structure of viviparid species in water bodies, causing higher ratios of middle-age (two to four year old) snails and decreased or absent young (up to one year old) and oldest (five−six year old) mollusks. The major factor here is high level of saprobity of water bodies, which is accompanied by formation of hypoxic zones and causes significant death rates in the youngest and oldest mollusks. Those are the most vulnerable age classes in mollusk populations.

这项研究提供了有关2007- 2018年乌克兰水体中的两种河蜗牛物种Viviparus viviparus（Linnaeus，1758）和V. contectus（Millet，1813）的种群特征的新信息。分析的特征包括物种分布，数量和生物量，年龄和性别比的种群结构，繁殖力，生长和产量的数据。确定了限制两个Viviparidae物种在不同生物群落中分布的生态因素（流速，温度，氧气浓度，pH，有机物质）。最近，出现的频率，和种群数量和生物量V.胎生和V. contectus已经观察到减少。可能的原因是气候变化和人为压力引起的环境条件下降。在乌克兰的水域，最大年龄为五年五胎生软体动物和六年五contectus。高的人为压力会扰乱水体中胎生动物的年龄结构，导致更高比例的中年（两至四岁）蜗牛，而幼龄（至一岁）和年龄最大（五至六岁）软体动物减少或消失。 。这里的主要因素是水体的腐烂程度高，伴随着缺氧区的形成，导致最年轻和最古老的软体动物的死亡率很高。这些是软体动物种群中最脆弱的年龄段。