Influence of the hydrological regime in the lower reaches of the Volga delta on natural fish reproduction

Abstract

This article considers the influence of the hydrological regime in the lower reaches of the Volga delta (based on the example of the Damchiksky site of the Astrakhan Reserve) during high water periods in the low-water year of 2012 and medium-water year of 2013 on the abundance of producers entering for spawning and the density of aggregations of juveniles of roach Rutilus caspicus, vulgaris rudd Scardinius erythrophthalmus, and river perch Perca fluviatilis. It is shown that the fish mass spawning in 2013 was more effective and occurred on floodplain spawning areas with the sequential succession of the investigated species, while the fish spawning was observed in eriks and was less effective in 2012. It was revealed that vulgaris rudd shows the highest adaptation to insufficient watering conditions.