Hemimysis anomala G. O. Sars (Crustacea: Mysidacea) — Immigration of a Pontocaspian mysid into the Baltic Sea
Salemaa, H.; Hietalahti, V. (1993). Hemimysis anomala G. O. Sars (Crustacea: Mysidacea) — Immigration of a Pontocaspian mysid into the Baltic Sea. Ann. Zool. Fenn. 30(4): 271-276 In: Annales Zoologici Fennici. Akateeminen Kirjakauppa: Helsinki. ISSN 0003-455X; e-ISSN 1797-2450, more |  |
| Keyword | Hemimysis anomala G.O. Sars, 1907 [WoRMS]
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| Abstract | Hemimysis anomala G.O. Sars, originally an endemic Pontocaspian mysid, was found in late summer 1992 at two localities in the coastal waters of SW Finland. This is the first observation of the occurrence of this deep sublittoral species in the northern Baltic Sea. H. anomala occurs swarming in wave-exposed archipelago habitats in the sublittoral belt of Mytilus and red algae. The swarms avoid direct light, aggregating in rocky crevices, under stones and in the cavities of the boulder shore to form larger groups in the daytime; but during the night dispersing in the algal zone, from 2 to 12 m in depth. Breeding females were found as late as at the end of October and females with fully developed ovocytes in April, indicating a long summer breeding period compared with other coastal Mysidacea in the northern Baltic. Because eurytopic crustacean populations have been introduced since the 50s from Pontocaspian estuaries into the freshwater reservoirs of the river Dnieper, the Volga and also into the Baltic basin, H. anomala seems to be a young anthropochorous neoimmigrant distributed via man-made water routes, instead of being a real glacial relict, not previously observed. The possibility of abrupt migration in the ballast waters of ships along Volgo-Baltic water routes is not, however, to be excluded. |
| Dataset | - NISES: AquaNIS. Editorial Board, 2020. Information system on Aquatic Non-Indigenous and Cryptogenic Species. World Wide Web electronic publication. www.corpi.ku.lt/databases/aquanis. Version 2.36+. Accessed 2020-09-09, more
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