During the last half century, 2 major crab species were introduced to the Barents Sea: red king crab Paralithodes camtschaticus in the 1960s; and snow crab Chionoecetes opilio in the 1990s. Early this century(2000), species from the southern boreal areas have expanded northward to appear in the Barents Sea, including the snake pipefish Entelurus aequoreus, snail ray Dipturus linteus, whiting Merlangius merlangus, grey gurnard Eutrigla gurnardus, and megrim Lepidorhombus whiffiagonis.
Both crab species appear to have become permanent residents. These fish species, however, have occurred in the Sea only during anomalously warm periods, and thus may be regarded as temporary residents (Berenboim and Sundet, 2011).
Invasion of alien species – spread of the representatives of various groups of living organisms beyond their primary habitats - is global in nature. Invasive species often act as biological pollutants, and may threaten an ecological security of the region. Their introduction and further spread often leads to the undesirable environmental, economic and social consequences.
Bioinvasion includes all cases of introduction of living organisms into the ecosystem outside of their original (usually natural) range. Therefore, the following examples represent different modes of biological invasion:
- natural movement associated with the population dynamics and climatic changes
- intentional introduction and reintroduction
- accidental introduction with the ballast waters and along with the intentionally introduced species, etc.
In the beginning of this century, due to the expansion of habitat range of fish from the southern boreal complexes, the following species, that can be considered temporary invasive species, appeared in the Barents Sea: snake pipefish (Eutelurus aequoreus), sail ray (Dipturus linteus), whiting (Merlangus merlangus), grey gurnard (Eutrigla gurnardus), megrim (Lepidorhombus whiffiagonis), However, the mentioned fish species can only, obviously, occur in the Arctic region waters of the Barents Sea in the period of anomalous climate warming.
On the other hand, invasive species that were deliberately or accidentally introduced to the Barents Sea as a result of human activity will probably stay in the Barents Sea for a long period of time. So, a special attention is paid to them in this chapter.
Also, Aporrhais pespelecani sp (Linnaeus, 1758) was recorded on the Murman coast of the Barents Sea. The finding of established population of the mollusc significantly (nearly 1000 km) extends its range eastward. A few species of gastropods were recently recorded for the first time on the Murman coast of Russia. These are four species of nudibranchs (Martynov et al., 2006), undoubtedly migrating eastward due to the warming of the Arctic ocean.
However, under various scenarios of the climate change processes in the Arctic, such period may last for a long time and there is a need to explore possibilities of range expansion of other boreal species and their impacts on indigenous communities. Further, it makes sense to elaborate on the most economically important species.
Table 2.4.8. Introduced species in the Barents Sea.
Red king crab (Paralithodes camtschaticus)
This species was deliberately introduced from the Far East to the Kola Bay and the adjacent waters of the Barents Sea by Russian scientists to enhance the fishing resources, in the 1960s. During the 1980s and 1990s they expanded to new areas and the crab reached the Norwegian shelf, and occupied practically all large fjords in the eastern Finnmark. Therefore, in the early 1990s, the crab caused heavy problems for the traditional fisheries. In addition, anxiety was expressed that this new species could cause serious harm to the biodiversity of the marine ecosystem. On the other hand, the red king crab was considered as a valuable fishing resource for the fishing industry in both countries. Therefore, a joint red king crab research was regularly discussed at the Joint Russian-Norwegian Fisheries Commission (JRNFC).
Snow crab (Chionoecetes opilio)
This species has not been deliberately introduced into the Barents Sea and is therefore considered to be an autoinvasive species. There are several hypotheses on how it was introduced and we think there are two probable ways. It may have migrated from the Beaufort Sea north through the Siberian Sea since it has been recorded in most areas along this track including the Kara Sea. Today distribution pattern in the eastern Barents Sea supports such a hypothesis. There is however, also a possibility that the snow crab larvae could be brought to the Barents Sea through ballast water from the crabs’ native areas.