Distribution, Population Structure, and Selected Biological Characteristics of Fish in the Genus Coilia (Engraulidae) in the Mekong Delta

Data on species composition and frequency of occurrence of the grenadier anchovies (Coilia) spp. is reported from the Mekong Delta (Vietnam) based on fieldwork materials. Information about two numerous species C. lindmani and C. rebentischii is obtained with respect to the spatial distribution and influence of various ecological factors on their density. Abundance of the Lindman grenadier anchovy C. lindmani is significantly higher in freshwater part of the delta compared to the estuary. The Multi-fingered grenadier anchovy C. rebentischii occurs only inside the estuary ecotone. The article is concerned with the effects of the environmental factors, such as oxygen content in the water, salinity, depth, and character of streambed substrate. No seasonal and year to year variations have been detected in terms of the population size. Some data on the biological characteristics are reported for the first time.