The old man of the sea

They say the sea is cold, but the sea contains
the hottest blood of all, and the wildest, the most urgent. …

And they rock, and they rock, through the sensual ageless ages
on the depths of the seven seas …

     — D. H. Lawrence, Whales Weep Not

News item: A bowhead whale caught recently was more than a century old. This animal, if not for its unfortunate encounter with an Inuit harpoon, might have proceeded about its stately cetacean business for decades to come — a point that underscores the impressive longevity of this order of mammals. (Link):

A 50-ton bowhead whale caught off the Alaskan coast last month had a weapon fragment embedded in its neck that showed it survived a similar hunt — more than a century ago.

Embedded deep under its blubber was a 3½-inch arrow-shaped projectile that has given researchers insight into the whale’s age, estimated between 115 and 130 years old. …

Calculating a whale’s age can be difficult, and is usually gauged by amino acids in the eye lenses. It’s rare to find one that has lived more than a century, but experts say the oldest were close to 200 years old.

Whales live a very long time in the wild, and it’s not even clear whether they undergo organismal aging as such. Certainly, they’re not immortal in a practical sense — but as Peter Medawar pointed out long ago, even a theoretically immortal population will be slowly winnowed over time, such that older animals will be rarer than younger animals. This, in turn, makes the contribution of older animals to future generations smaller, thereby weakening the strength of selection on genes that act in late life, and setting the stage for the evolution of aging per se. Has this happened with whales? (What possible experiment could address the issue?)

Whether they age or not, whales demonstrate that mammals can live at least twice as long as humans, raising the question of how they do it. As intractable a model system as even small whales might be for the average bench scientist, it would nonetheless be fascinating to study age-related phenomena in these creatures, perhaps in a cell-culture system where we could ask questions about their cellular senescence, DNA repair, and oxidation.

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4 comments

  1. Thanks for this interesting perspective on the very old bowhead whale. Have you thought about fish that live long? Is there something interesting for you there?

    Here’s a reference to a 100 year old rockfish recently caught off Alaska. These fish perhaps don’t undergo “aging” as such, because the oldest females seem to be the most valuable for reproduction.

  2. That’s interesting about the rockfish — thanks for the link. I knew about the big carp called koi living for really astonishing lengths of time (~200 years), but I hadn’t heard about wild fish.

    The increased reproductive value is also very interesting in the context of evolution of aging — if the fecundity of a female increases over time, then it might actually be possible for older animals to have a larger contribution to the next generation than young animals, defeating the tendency of selection pressure to weaken over time, and retarding the evolution of aging in that organism.

  3. Another fact to add–offspring of older female black rockfish are of higher quality, hence higher reproductive value. These fish have live young, and larvae from older females live longer until starvation, so they have more time to find their first meal, which is a big deal for a larval fish.

    Numbers of offspring per pound goes up with age, and survival of offspring goes up with age. These “Big, Old, Fat Female Fish” (termed BOFFFs) are truly special individuals in their species, and efforts are underway to protect them from fishing that would otherwise eliminate old fish.

    Seems to me to be contrary to most concepts of aging. Curious.

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