Impact of the red king crab and the snow crab on the Barents Sea megabenthic communities

Abstract

The work is devoted to problems of mutual adaptation of two invasive commercial crab species, the red king crab Paralithodes camtschaticus and the snow crab Chionoecetes opilio, and the recipient ecosystem of the Barents Sea. Data on the distribution of megabenthic communities obtained for 2006–2020 are provided. The dynamics of invasive crab populations is analyzed, and related changes that occurred in the Barents Sea bottom communities during this period are studied. Mechanisms of the impact of crab species on bottom communities and prospects for their colonization of the Barents Sea are discussed. The research is based on the results of quantitative and taxonomic analysis of bycatch in 6,010 by-catches with a Campelen 1800 trawl performed in the Barents Sea in 2006–2020 during the joint Russian–Norwegian ecosystem survey on RV of the Polar branch of VNIRO and the Institute of Marine Research. The expansion of the range and increase in abundance of the red king crab since the early 1990s led to its colonization of the vast water area of the southern Barents Sea. In 2006–2010, this species dominated in megabenthic communities around the Murmansk Rise and Kaninskaya Bank. In 2016–2020, the red king crab spread north and east – up to the Kolguev Island and the southern slope of the Goose Bank. An increase in abundance of the snow crab resulted in its colonization of a huge area in the Barents Sea: from the Pechora Sea to the Franz Josef Land archipelago and from the Novaya Zemlya archipelago to the Spitsbergen archipelago. In 2006–2010, the snow crab abundance started to increase in the Novaya Zemlya archipelago area; there, it was a subdominant species in communities of soft sediments of the Goose Bank. In 2011–2015, the snow crab began to dominate in communities of the Goose and Novaya Zemlya banks and the northern Central Bank. At the same time, it continued to increase its role as a subdominant species in almost all megabenthic communities near the Novaya Zemlya archipelago. Later, in 2016–2020, this species dominated in benthic communities on the boundary with the Kara Sea between the Novaya Zemlya and Franz Josef Land archipelagos, on the slopes of the Novaya Zemlya Bank, near the Central Bank, and in the Southern Novaya Zemlya Trench. Its range increased and covered the area from the Franz Josef Land and Novaya Zemlya archipelagos to the Perseus Bank in the west and to the Pechora Sea in the south. As shown, under current climatic conditions, the red king crab will remain part of megabenthic communities in the southeastern Barents Sea. The snow crab will continue to migrate from the east to the western Barents Sea, up to the Spitsbergen archipelago, where similar benthic communities exist; in case of colder weather, its migration will occur faster. A scenario is possible in which shallow waters of the Spitsbergen archipelago will be a new reproductive center of the snow crab population in the Barents Sea, along with the current center near the Novaya Zemlya archipelago.

Keywords

• Barents Sea
• megabenthos
• bottom communities
• red king crab
• Paralithodes camtschaticus
• snow crab