Penguins to jelly fish in Antarctica?

The referenced article cites studies that predict krill populations declining due to loss of sea ice accompanying global warming. The study states that krill will be replaced by tiny copepods, too tiny for penguins to feed on, but excellent for jellyfish. Hence penguins (and whales) will decline, and jellyfish will thrive.

While I don't question the science, I do wonder what time frame we are talking. Antarctic sea ice extent has been quite stable from what I have read. Yes, it is forecast to decline more rapidly as the ozone hole over the Antarctic disappears over the next 2 decades, but I also have faith in the krill adapting during any prolonged change in sea ice extent.

 

Above: Gentoo Penguin feeding krill to her young. Photo by Bill Fintel