Impact of the Alaskan Stream flow on surface water dynamics, temperature, ice extent, plankton biomass, and walleye pollock stocks in the eastern Okhotsk Sea

Year-to-year changes of the Alaskan Stream surface flow, forming the northern boundary of the western subarctic cyclonic gyre in the Pacific, impact the dynamics of water in the eastern Okhotsk Sea. It is shown by Lagrangian simulation of transport of the Alaskan Stream waters in 20year-long AVISO velocity field and direct computation of the corresponding fluxes that an intensification/weakening of the Alaskan Stream current leads to increased/decreased northward fluxes in the areas of the Krusenstern and Fourth Kuril straits connected the Okhotsk Sea with the Pacific Ocean. Enhancement of the Alaskan Stream flux is accompanied by an increase in water temperature and decreasing ice area in the Okhotsk Sea in winter. The Alaskan Stream surface flux is shown to be negatively correlated with satellite-derived chlorophyll-a concentration in May from r=−0.68 to −0.73 in 1998–2013 and with winter–spring biomass of large-sized zooplankton with r=−0.70 in 1995–2012. It is positively correlated with winter–spring biomass of small- and medium-sized zooplankton in the eastern Okhotsk Sea with r=0.74 in 1995–2012. •Impact of the Alaskan Stream on dynamics and biology in the Okhotsk Sea is examined.•Lagrangian simulation and estimation of transport of Alaskan Stream waters.•Increase of the Alaskan Stream flux increases seawater temperature and ice-free area.•This flux negatively correlates with chlorophyll-a concentration.•This flux positively correlates with the small- and medium-sized zooplankton biomass.