Observations are made at fixed stations, the coordinates of which have been determined in advance in 3 largest ports of Latvia Liepāja, Ventspils and RD+ga. Frequency of sampling 3 times in 6 years twice in a year during spring and summer seasons, in a phytoplankton bloom maximum period. Methods according to the HELCOM/OSPAR Port Survey Protocol. - Hydrobiological parameters determined: - - Abundance, species composition and biomass of phytoplankton, zooplankton and zoobenthos organisms (details see in the sections LV-4.1.2., LV-4.1.3. and LV-4.1.4.); - - mobile epifauna (sampling with pots (for crabs), by scraping from constructions and sedimentation plates) - Physical and chemical parameters determined in the water column: - - CTD probe (temperature, salinity, turbidity, dissolved oxygen), Secchi depth, chlorophyll a (details see in the sections LV-4.5.2., LV-4.5.4. and LV-4.5.5.); - -Chemical parameters determined in the near-bottom layer (details see in the sections LV-4.5.4. and LV-4.5.5.: temperature, salinity, oxygen saturation. - Human pathogens: Intestinal enterococci, Escherichia coli, Vibrio cholera (testing according to the EN ISO methods: 7899-1 or7899-2, 9308-1 or 9308-3, no standard method for Vibrio cholera yet) - Ground type and fractions visual assessment during the sampling.

3 national sub-programmes for monitoring of the Chinese mitten crab have been developed: 1) For monitoring of planktonic phase of development samples are collected with standard net construction with opening 57 cm and mesh size 100 microns. Observations are made at fixed stations, the coordinates of which have been determined in advance by sampling on certain depths. Frequency of sampling up to 9 times per year. Species composition, abundance and biomass is determined according to the HELCOM recommendations in COMBINE manual in Guidelines for monitoring of mesozooplankton. The method is suitable for qualitative (species composition) and quantitative (biomass) detection of zooplankton organisms in nature water samples. 2) For monitoring of adult Chinese mitten crabs abundance information about by-caught individuals in industrial coastal fishing is used. Information is collected from fishermen. Comparison of data about by-caught crabs in the form (CPUE or catch per unit effort) over seasons and coastal areas is made. Industrial fishing takes place regularly throughout the year, covering most of the coastal territory of Latvia and the information obtained will be spatially representative. It is planned to use one coastal fishing company in each coastal parish of Latvia, by agreeing to register information on the duration of the fishing act, the fishing gear used and the Chinese mitten crabs caught in them during the whole fishing season. In addition to this collection of biological crab samples are also planned in order to register their gender, maturity, morphological parameters (and genetic material). Biological analyses of crabs in the long term scale would help answer the question whether this species is able to adapt and reproduce successfully in Latvian marine waters. 3) Public monitoring of the distribution of these crabs in an internet site will be created, where the Latvian public can report on findings of Chinese mitten crab. The information reporting page defines the parameters to be reported (e.g. date, time, location coordinates, required images, etc.). LHEI, in cooperation with the DAP, will assess the quality of the reported data to be used for monitoring Chinese mitten crabs. Data/samples for round goby are obtained from: 1) coastal commercial fishing trips and from coastal fishing logbooks, 2) coastal fish monitoring and 3) benthic fish surveys.