Invasion in the White Sea: the first discovery of the American Copepod Eurytemora americana (Copepoda, Calanoida)

Abstract

A new species Eurytemora americana has been discovered near the Solovetsky Archipelago in the White Sea. The discovery has been confirmed morphologically, and the key species-specific traits have been analyzed: common view, P5 of females and males, structure of the male geniculate antenna. These traits have revealed the highest similarity between the study population and the Pacific E. americana. Genetic analysis has confirmed the morphological data. Differences between the White Sea and Pacific populations are minimal and amount to 1.4—1.7% for the mitochondrial CO1 gene. The researchers indicate that the conditions in Blagopoluchiya Bay are similar to those in native habitats, while high anthropogenic load and rising average annual water temperatures in the White Sea also facilitate the naturalization of this species in the study area. Given the high abundance of E. americana in the study area, it can be assumed that this species has a high potential for dispersal in coastal, freshened areas of the White Sea. However, near the Solovetsky Archipelago, this species appears to be in competition with crustaceans of the genus Acartia, suggesting a mutually exclusive relationship. It is expected that the studied species will find other suitable water areas in the White Sea, and possibly beyond. Considering the relatively large size of this invader for a zooplankton species, as well as its high population density in the search area, it can be assumed that E. americana will become another food source for juvenile fish in estuaries and freshened areas of the White Sea.