Development of snow crab Chionoecetes opilio (Crustacea: Decapoda: Oregonidae) invasion in the Kara Sea

摘要

With current climate trends, longer ice-free periods and increased human activity are observed in the previously hard to access Arctic Siberian seas. This providesfor a rare opportunity to observe the progress of species invasion in pristine areas. The snow crab, Chionoecetes opilio, is a unique example of an alien Brachyura crab in the Arctic. Its distribution, population size structure, as well as biotic and abiotic conditions affecting its survival in the Kara Sea are discussed. Crabs were collected using trawl sampling in 2014. It has been estimated that the invasion took place in the late 2000s through the northern and eastern borders with the Barents Sea. Presently, snow crabs are found throughout the western part of the sea, from Kara Gates to St. Anna Trough; the entire area between Yamal Peninsula and Novaya Zemlya; and the northeastern shelf of the sea. Benthic abiotic conditions of the Kara Sea are unlikely to limit survival and further progress of snow crab population. However, the length of the ice-free period could limit its reproduction potential. The collected data do not allow us to presume the existence of a reproducing population, yet the presence of a settler-size group in the central part of the western Kara shelf could indicate local recruitment. Food availability in the Kara Sea is unlikely to limit growth of early benthic stages of snow crabs such as those collected in 2014. However, the question remains open whether benthic productivity is sufficient to allow these crabs to reach commercial sizes.