Assessment of the invasive potential of boreal crustaceans in the Barents Sea under climate change conditions

The Barents Sea, a critical Arctic ecotone and a vital fishing region, is undergoing rapid climatic transformation. This process includes Atlantification (intensified inflow of Atlantic waters), progressive warming of bottom layers (1.5–2°C over the past 30 years), and a 20–30% reduction in seasonal ice cover. This study investigates the impact of these changes on the invasive potential of boreal commercial crustaceans – the edible crab (Cancer pagurus), Norway lobster (Nephrops norvegicus), and European lobster (Homarus gammarus) – under three climate scenarios (Shared Socio-Economic Pathways: SSP1-1.9, SSP2-4.5, and SSP5-8.5). Using ensemble species distribution modeling (SDM) integrated with Bio-ORACLE oceanographic data and CMIP6 climate projections, we assessed their potential colonization of the Barents Sea by 2100. Results revealed that under current conditions, the species’ ranges on the Barents Sea shelf are limited to narrow coastal zones off northern Norway (1–2 thousand km²). However, under the extreme SSP5-8.5 scenario (projected 3°C bottom temperature rise by 2100), suitable habitats for C. pagurus would expand to 76.3 thousand km², for N. norvegicus to 67.9 thousand km², and for H. gammarus to 8.5 thousand km², predominantly in the southwestern Barents Sea. The range of H. gammarus would remain constrained to 1–2 thousand km², dependent on rocky biotopes (7–12% of the southwestern shelf), while C. pagurus and N. norvegicus would associate with soft sediments (60–70% of the shelf). Competition with the invasive Kamchatka crab (Paralithodes camtschaticus) may create biotic barriers, though its projected northeastward shift toward Kolguev Island and Novaya Zemlya is expected to reduce pressure on southwestern areas, opening "ecological corridors" for boreal species. Modeling confirmed the critical role of geomorphological factors: fragmented rocky habitats form isolated "ecological islands", limiting H. gammarus dispersal, whereas extensive soft sediment zones facilitate the expansion of C. pagurus and N. norvegicus. The SDM approach demonstrated acceptable efficacy in predicting range shifts under climatic uncertainty, highlighting its potential value for ecosystem-based management and ecological monitoring in the Barents Sea.