October 10, 2019 — The following was released by NOAA Fisheries:
New genetic research suggests that unprecedented summer abundances of Pacific cod in the northern Bering Sea were due to escalating movement from their core habitat under recent warm conditions.
Until recently, Pacific cod were rarely encountered in the northern Bering Sea. Fishery surveys in the 1970s reported “trace amounts” of cod there. A 2010 Alaska Fisheries Science Center survey estimated that the entire northern population amounted to about 3% of the large southeastern Bering Sea stock that supported a valuable commercial fishery.
Then in 2017, the summer survey recorded dramatically higher abundances in the north: a 900-fold increase since 2010. In the same year, southeastern Bering Sea abundances were down 37% from 2016. Strikingly, the increase in the north nearly matched the decrease in the southeastern Bering Sea.
A 2018 survey revealed an even more remarkable shift: there were more cod in the northern than southeastern Bering Sea.