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Field Trip Reservoirs
In the period 26 October – 7 November 2010, a field survey in the reservoirs Koprinka and Zhrebchevo was conducted. The two reservoirs are located on the Tundzha River, Aegean Sea basin; they are used for power generation, water abstraction for irrigation, aquaculture and recreational fishing. Three sites were sampled in the Koprinka Reservor and 4 sites in the Zhrebchevo Reservoir. The following samples were collected: water chemistry, bacterioplankton, phytoplankton, phytoplankton pigments, zooplankton, epilithic diatoms, benthic macroinvertebrates and fish.
During the autumn sampling, the water level in the Zhrebchevo Reservoir, which is infested by zebra mussels (Dreissena polymorpha), was 5-7 m lower than the spring sampling in May. The significant reservoir drawdown caused massive die-offs of zebra mussels in the littoral. The shores were covered with zebra mussel shells attached to stones, remains of buildings, different objects, trees, branches, plants, as well as animals, such as unionid mussels and gastropods. A thick layer of zebra mussels was observed on the concrete surface of the water intake tower. Dense colonies of live mussels were found attached to the floating fish cage facilities and nets in the reservoir.
We are grateful to Mr Kalcho Petrov and Irrigation Systems EAD – Sliven, to Mr Ivan Valchev and the National Agency of Fishery and Aquaculture – Stara Zagora, and to Mr Nikolai Radukov and the Marine Club “Sevt III” - Kazanlak for their help during the field sampling

Zhrebchevo Reservoir


Koprinka Reservoir


This website is developed with support from the Bulgarian Science Fund, Ministry of Education, Youth and Science,
within the Project "Assessment and Management of Dreissena spp. Invasions in the Bulgarian Water Bodies",
Contract Number: DO-02-283/2008.

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