The shallowest zones of coastal lagoons are particularly appropriate nursery habitat for many fish species by providing refuge from predators and abundant food, among other benefits. However, little is known about the characteristics of fish assemblages and their relationship with environmental factors in these areas. The main objective of this study was to investigate the abundance and composition of the fish assemblages in the shallow zones ($\le$1 m) of four coastal lagoons in the Central Mexican Pacific and determine the correlation of their spatial and seasonal variations with selected abiotic variables. Fish samples were taken with a beach seine in the months of May and December during two consecutive years. Simultaneously, the physical and chemical variables of the water were measured, and the particle size of the sediment and content of organic matter were determined. A total of 26 016 fish belonging to 60 species were collected, but only eight species (Poeciliopsis turrubarensis, Lile stolifera, Poecilia butleri, Eucinostomus currani, Anchoa sp, Gerres simillimus, Atherinella guatemalensis and Mugil setosus) accounted for more than 80% of the specimens. Significant differences in the composition of the fish assemblages between lagoons were found. The changes were principally related to the type of communication with the ocean, second to physical and chemical variables, primarily salinity, followed by size of the sediment particles (% of mud or sand). Observed seasonal changes could have been related to environmental and biological factors (e.g. recruitment) acting synergistically. No evidence was found that the state of eutrophication of the lagoons is severe and could be affecting the composition of the fish assemblages.

沿海泻湖最浅的区域是许多鱼类特别合适的育苗栖息地，可提供躲避掠食者的庇护所和丰富的食物，以及其他好处。然而，人们对这些地区鱼类组合的特征及其与环境因素的关系知之甚少。本研究的主要目的是调查浅水区鱼类群落的丰度和组成。$\le$1 m) 中墨西哥太平洋的四个沿海泻湖，并确定它们的空间和季节变化与选定的非生物变量的相关性。连续两年的 5 月和 12 月在海滩围网中采集鱼类样本。同时测定水体的理化变量，测定沉积物的粒径和有机物含量。共 收集到 60 种26 016 条鱼，但只有 8 种（Poeciliopsis turrubarensis、Lile stolifera、Poecilia butleri、Eucinostomus currani、Anchoa sp、Gerres simillimus、Atherinella guatemalensis和Mugil setosus)占标本的80%以上。发现泻湖之间鱼类组合的组成存在显着差异。这些变化主要与与海洋的通信类型有关，其次是物理和化学变量，主要是盐度，其次是沉积物颗粒的大小（泥或沙的百分比）。观察到的季节性变化可能与协同作用的环境和生物因素（例如招募）有关。没有证据表明泻湖的富营养化状态很严重，可能会影响鱼类组合的组成。