In order to analyze and confirm the sturgeons migration routes, in 2013 the researchers from the National Institute for Research and Development in Environmental Protection installed two monitoring systems on Chilia branch, at the confluence with Bastroe branch (upstream and downstream of it) additional to the two systems installed in 2011 in Isaccea and Tulcea.
Monitoring systems installed on the Chilia branch
Thus, during the period 2011 – 2014, the researchers of INCDPM Bucharest tagged and monitored during the reproduction migration on the Lower Danube over 250 specimens of sturgeons from the 4 species present on our territory: beluga, stellate, starlet and Russian sturgeons. From de figure presented below can be observed that the Russian sturgeons represents only 1% of the total, situation which requires the identification and application of rapid solutions which will lead to an increase of the population level for this species, otherwise existing the risk that in the near future it will disappear from the Danube area.
Captures recorded during the period 2011-2014
The results of a detailed analysis for 2012-2014 period showed that in 2013, during the autumn period, 69% of all sturgeons descend to the sea used the Tulcea branch, while at the end of the spring migration in 2014 the proportion of specimens which descended to the sea on the Chilia branch was the same as in 2012, namely 53%.
The identified solution regarding the intensification of sturgeon routes monitoring by installing some additional stations upstream – downstream from the Bastroe channel led to an increase of the confidence level regarding the information on the sturgeons’ behavior during their migration.
The research has shown that the sturgeons use as migration routes to the Black Sea the Chilia and Old Stambul branches. In this situation, if the Chilia branch becomes an inert zone related to the possibility of sturgeons migration, in conjunction with the situation encountered on the Sulina branch, the only possibility for the migration of these species, protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), will remain St. George branch, thus presenting a major risk of reducing the possibility for sturgeons migration.