The fish of the family Atherinopsidae (Teleostei: Atheriniformes) from mexican iso and hypersaline coastal lagoons

The Order Atheriniformes includes six families, represented in Mexico by two of them: Atherinopsidae species are restricted to the freshwater highland lakes and shore estuarine species from both Mexico coasts. Atherinidae is composed by two marine shore species from the Gulf of Mexico. The new world silversides are located in the neritic zone and the epilimnion of lakes and rivers of highlands as well in the coastal plain. This group, comprises several marine species that goes into the continental waters and are found in isohalyne and hypersaline coastal lagoons. These fish are interesting because their abundance in the aquatic ecosystems as well as their ecological role in low and medium trophic levels, are important commercially because they are part of some local or regional fisheries. Several taxonomic and biological information of each species is included. Was concluded, that there are two taxonomic groups well defined: one in the Pacific and the other one in the Atlantic. From the ecological point of view, there are seven estenohalin that also have several salinity tolerance levels.