Gray whales (Eschrichtius robustus) return from Arctic
feeding grounds to lagoons in Mexico each winter to
give birth. New genetic results indicate that in the past,
the number of whales returning to these lagoons may
have been much larger.
Photo location: Laguna San Ignacio, Mexico.
Credit: Geoff Shester
With large numbers of gray whales swimming south from the Arctic in terrible condition, here’s another development that suggests something fundamental has shifted in the marine food chain of the Far North ocean.
Gray whales may have once numbered more than 96,000 in the North Pacific Ocean — churning up muck and plumes that fed millions of seabirds and replenished the Bering and Chukchi seas with nutrients, according to new research published this week in the Proceedings of the National Academy of Sciences.
This genetic analysis suggests the whales were once three to five times more numerous and, as a result, have not yet come close to recovering from decimation by commercial whaling.
The findings raise stunning implications about how little people really know about the marine world. We do not, even now, fully appreciate how much the ocean has changed from pre-historic times.
Gray whales were heralded as one of the world’s great conservation success stories and pulled from the Endangered Species list. When whales began showing up very skinny, with bones protruding, possibly near starvation, some biologists speculated that the population had expanded beyond its historic limits.
Now it appears that the grays haven’t actually rebounded. The population hasn’t broken historic limits. And their pending starvation may be a harbinger: Something has gone wrong in the North Pacific.
“Despite our best efforts,” said Stanford University marine biologist Steve Palumbi, in a story posted online, “these genetic results suggest gray whales have not fully recovered from whaling. They might be telling us that whales now face a new threat — from changes to the oceans that are limiting their recovery.”
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