Maybe this is the next motto, or ploy, by Japanese whalers determined to keep bringing giant cuts of meat from the Southern Ocean. “Eat Whales! Save the Penguins!” In PNAS this week are results of a study of population declines among penguins, chiefly the chinstraps and adelies that nest along and near the quickly-warming Antarctic Peninsula. And while heavy snowfall and egg-killing melt on rookeries, plus shrinking of seasonal pack ice, are factors in their struggle,  the study identifies faltering shoals of krill as its prime suspects. Mortality of fully mature penguins, it appears, is not terribly high, but the failure of young but fledged penguins to get through their first seasons at sea on the own points suggests they are just not getting enough to eat. And factors in krill loss including commercial harvesting and nature’s biggest krill-eating machines, baleen whales such as blues, fins, and sei whose numbers may be rising. The irony is that while the study says krill harvesters are doing adelies and chinstraps no good today, the birds’ surge in numbers early in the last century was probably also mankind’s doing – via slaughter of whales.

‘Must be a press release out there. (*UPDATE 1- Joanna Knight at the Lenfest Ocean Program, a sponsor of the study, sent the press release link, now down below in Grist. Thank you Jo.)  The research was by scientists at with the National Marine Fisheries Service stationed in La Jolla, CA, and at the Scripps Institution of Oceanography there as well.

Stories:

• BBC – Mark Kinver: Penguins suffer as Antarctic krill declines ; Surely krill in this hed is plural. Ergo they decline. If one wrote “as fish declines” you’d think we’re talking about one guppy. Nothing wrong with story, at a quick read.
• Nat’l Geographic – Brian Handwerk: Penguins Numbers Plummeting – Whales Partly to Blame ; That’s a brave angle in the hed, but legit. The study seems to put more emphasis on rising whale numbers than on krill fisheries, even it documents the rapid increase in harvests. But to write anything about great whales that suggest there is a downside to having more of them takes some nerve. (UPDATE 2: The lead author of the research says there is no evidence whales are a major factor).
• Reuters- Deborah Zabarenko: Fewer penguins survive warming Antarctic climate ; This one focusses on the decrease in ice as a major factor in declines in krill, which do depend in part on ice floes and the algae that grow on their bottoms. But a reading of the PNAS paper finds as much reference to whales and krill harvesting as to the dependence of krill on under-ice nurseries.
• NY Times – Nicholas Bakalar: Observatory: Taking a Second Look at Penguins’ Decline ;
• CBS News – Wynne Parry – Antarctic warming may be starving penguins ;
• AFP – Kerry Sheridan : Young penguins dying due to lack of food ; Nice clean hed, to the point. The story however declares that “melting sea ice cuts back on the tiny fish they eat.” Later it says krill, and calls them crustaceans. Maybe an editor decided they are fish?

There are plenty more but time to wrap up for the day. One factor in the paper, however, that is fascinating but got little or no attention in the stories I had time to read, is that fossil evidence from the debris under long-lived rookeries indicates that a long time ago, presumably when whales were vacuuming up krill like crazy, adelie penguin diets comprised mostly small fish. It suggests that, push comes to shove, they could go back to fish. On the other hand, adelies are particularly habituated to feeding under and around sea ice, which is fading.

Grist for the Mill: Lenfest Press Release ; Report Summary ;

- Charlie Petit

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