KMXT 100.1 FM Public Radio in Kodiak, Alaska
Kayla Desroches/KMXT
A biologist went over climate change and its effects on marine life at Kodiak’s commercial fisheries trade show, ComFish, last week.
Mike Litzow, a research faculty member with the University of Anchorage Fairbanks, explained how human-sourced carbon dioxide has interfered with what would otherwise be a natural ebb and flow of warming and cooling waters in the ocean.
“As you go forward with more carbon dioxide, you shift the mean, but what you really shift is the extremes, so we’re expecting we’re going to more and more of those extreme events.”
He said NOAA scientists have observed the possible effect of changing water temperatures on fish populations in the northern Bering Sea.
“If you compare 2017 biomass to 2010 biomass, walleye pollock biomass in that northern area went up 6,000 percent, [Pacific cod] biomass in that area went up 900 percent, Arctic cod… went down 90 percent, so in seven years that’s a really remarkable change.”
He said Bering Sea ice cover also appears to be decreasing, and more quickly than expected.
While pacific cod may now be flourishing in the Bering Sea, the Gulf of Alaska is still warmer – in recent years especially.
Litzow said juvenile pacific cod show poorer survivability in those warmer waters and tend to grow to smaller sizes.
