Data from Swedish environmental monitoring of abundance of Ringed seal. Swedish monitoring of Ringed seals started in 1995. The monitoring program was initiated by the Swedish Environmental Protection Agency and later the Swedish Agency for Marine and Water Management took over the responsibility and financing of the program. The monitoring is performed by the Swedish Museum of Natural History. Data is stored in the database SHARK, hosted and maintained by the Swedish Meteorological and Hydrological Institute. Monitoring of ringed seal is performed by counting seals in transects from airplane. More information is available in Swedish at https://www.havochvatten.se/hav/samordning--fakta/miljoovervakning/miljoovervakningens-programomrade-kust-och-hav/delprogram-sal-och-havsorn.html