This checklist summarizes information on the parasites of Latvia fishes contained in the world literature dating to the end of 2005. Information is presented in the form of parasite-host and hostparasite lists and includes 305 named species of parasites, distributed among the higher taxa as follows: Protista – 42, Myxozoa – 49, Digenea – 38, Monogenoidea – 81, Cestoda – 33, Nematoda – 31, Acanthocephala – 11, Hirudinida – 2, Mollusca – 6, Branchiura – 2 and Copepoda – 10. Also included are many records of parasites not identified to species level. The Parasite-Host List is organized on a taxonomic basis and provides information for each parasite species on the environment (freshwater, brackish, marine), the location (site of infection) in or on its host(s), the species of host(s) infected, the known geographic distribution (by major waterbody) in Latvia, and the published sources for each host and locality record. The Host-Parasite List is organized according to the taxonomy of the hosts, and includes for each host, the English language, Latvian and Russian common names, environment (freshwater, brackish, marine), status in Latvia (native or exotic) and the list of parasites reported. Both lists are accompanied by remarks, as warranted, giving specific information on points of systematics, nomenclature, possible misidentifications, introductions, life cycles, etc. Citations are included for all references and parasite and host indices are included.

The parasite fauna of fishes of Latvia has received considerable attention. Nevertheless, parasites have been recorded from only about 45 percent of the more than 114 species of marine and fish occurring in the country’s waters. The common freshwater fish species (particularly those having economic importance, such as the cyprinids, percids, esocids and salmonids) have been particularly well studied, providing a good general picture of their parasite faunas and data having value for use in faunistic analyses.