A boat field trip was carried out along the Bulgarian stretch of the Danube River - from Vidin (r. km 796) to Ruse (r. km 502) in the period 2nd-10th September 2012. The field trip was organized within the framework of the project "Potential threats to environmental and economic sustainability in the Danube and Black Sea region: Danube River as invasive alien species corridor" and funded by the International Association for Danube Research (IAD) and East and South European Network for Invasive Alien Species (ESENIAS). Scientists from the Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences and Biological Faculty of Sofia University participated in the field trip.

Samples for water chemistry, phytoplankton, zooplankton, epilithic diatoms, macrophytes, benthic macroinvertebrates and fish were collected at 14 sites. The samples and data collected will be further analyzed for presence and quantitative characteristics of invasive alien species, associated communities and ecological conditions.