Inland Waters Laboratory is leading research structure in investigation of fish and crayfish in the Latvian inland waters (rivers, lakes, and others). Objectives of the research are primarily connected with the assessment of fish stocks and natural restocking of migratory fish. Laboratory’s researchers to great extent are involved in processing of fisheries information and creation of the database. The data on fishing, angling and fish artificial restocking in Latvia have been analyzing and archiving in the Laboratory. Researchers carry out expeditions and collect the data about the main commercial fish species as well as other freshwater fish species. Evaluating the state and structure of fish stocks in the lakes researchers perform control trawlings and fish biological analysis, including age determination of the main species to get estimates of their growth. The surveys on crayfish are performed mainly in order to estimate a distribution of four crayfish species in Latvia. In 2005, carrying out a survey in the River Lielupe basin, a new in Latvia crayfish species Orconectes limosus was identified. Since 1992 Laboratory’s researchers have conducted surveys on 294 lakes and artificial water reservoirs, using standard nets, beach seiners and electrofishing method.
Regular monitoring of salmonids in basins of the rivers Salaca, Gauja and Venta, as well as other rivers, is producing estimations of the state of wild salmon and sea trout populations. In frame of monitoring a survey on migrating smolts of salmon and sea trout in the river Salaca, as a national salmon index river, is conducted. The survey in the river Salaca includes also a tagging of salmon smolts in order to estimate a number of smolts migrating to the sea. The obtained data are used for general assessment of wild salmon stocks in the Baltic Sea. Since 2010 the salmon monitoring in the river Salaca is also a part of the Fisheries Data Collection Programme.
Electrofishing surveys, since 1992, have been conducted in 197 rivers. These investigations include performing of fish biological analysis, registration of hydrology and hydrochemistry parameters, and also studying of fish diseases and parasites.
In 2007 the fish monitoring programme for Latvian rivers was founded. Every year fish communities are monitored in 120-130 sites all over the territory of Latvia. In 2008 in the river Gauja golden spined loach Sabanejewia aurata, a new fish species in Latvia, was identified.
Specialists of Inland Waters Laboratory are involved in creation of the “Latvian 
National Fisheries Data Collection Programme (823.74 Kb)” collecting biological data on salmon, sea trout, pike-perch and eel. The Laboratory has performed a lot of work in preparation of fish stocks management plans. Thus, in 2008 the Eel Stock Management Plan was prepared, submitted to and confirmed by European Commission. At present documentation accordingly the plan and its objectives has to be prepared.
Laboratory’s specialists are responsible for the estimation of the losses of fish resources due to economic activities and providing of corresponding expert’s reports.
On the basis of scientific data Inland Waters Laboratory takes a part in legislation development, elaboration of the annual recommendations on the national management of commercial and recreational fishery in inland waters, and in giving the public services in research and aquaculture works.
International cooperation
Participation in the International Council for the Exploration of the Sea (ICES) working groups:
Working Group on Baltic Salmon and Trout (WGBAST),
Working Group on Marine Recreational Fishery (WGSMRF),
Joint EIFAC/ICES Working Group on Eels (WGEEL).