Monday, August 26, 2013

Rain Finally Brings Relief to Southeast Alaska's Humpback Salmon

If you’re ever in need for rain assistance during a drought, call on us.  Posting our last installment on humpback salmon and low water brought back Petersburg’s traditional rain-washed skies.  The rock outcrops that Karen’s “babies” couldn’t get over because the veil of water was too skinny, became raging torrents that her “babies” couldn’t get over because the terrain was more like a flattened fire hose.

The rain augmented by big tides also brought in even more salmon to the stream that already had more salmon than could spawn successfully.  That brought even more tears to Karen’s eyes as she contemplated all the challenges the salmon had surmounted to get to their spawning ground only to find “no room at the inn.”  OK, they still got to spawn, but not without wrecking the chances of those that came before.

Two years ago these humpback salmon started life as fertilized eggs.  Emerging from the gravel in the spring of 2012, they had bucked the odds just by surviving floods and ice during the winter of 2011/12.  Checking out their new neighborhood, they were quickly swept downstream to face a gauntlet that would cause the toughest Marine to turn ashen with fear.  As they migrated through Frederick Sound out into the Gulf of Alaska seemingly everybody wanted to eat them -- kingfishers, great blue herons, millions of sea birds, bald eagles, gulls, sharks, pollock, halibut, other salmon (especially coho salmon but even some pink salmon), sea lions, humpback whales -- the general rule that pink salmon must learn to survive -- if it’s bigger than you and has pointy teeth, don’t accept it’s invitation to join them for dinner. 

Then, as that genetically programed urge to procreate began to replace common sense, they headed back to where they were born, City Creek.  En route the nets of commercial fishermen (and women), the lures of sport and subsistence fishermen (and women) were added to their obstacle course.  Harbor seals welcomed them at the mouth of City Creek -- perhaps even a bear or two at night.  Whew -- still thousands made it “home” where Karen greeted them with open camera lens.  She even rescued those she discovered stranded in isolated pools when falling tides separated them from their companions but not hungry gulls and eagles.  To her frustration, all turned around and got stuck again.

Thus, during almost daily patrols this past week, Karen documented the arrival and health of her newly adopted “family”  -- surrogates for our recently departed Niko.


It seems like there's "no room at the inn" as humpies completely fill a pool immediately below the torrent leading upstream.

Still a male pink salmon (as distinguished by the hump on his back) struggles to get further upstream.


Rising water after the rain brought in another wave of pink salmon to battle the force of the water to get upstream.


And still more crowd into the stream in a seemingly endless "phalanx" of fish move into the creek.


Only in quieter backwaters does there seem to be any room for more salmon -- areas likely to freeze soid in winter where eggs are unlikely to survive.


Stranded by falling tides in the intertidal zone, Karen rescued this male only to see him swim back to his chosen territory.


When Karen can photograph a pink salmon from directly overhead you know a bear or bald eagle can easily get just as close.  The scratches on the top of its head show the beating these fish take in their struggle to reach their spawning grounds.


Two humpback salmon made obvious by the fungus growing on their backs swim under my boot.  As all species of Pacific salmon reach fresh water, their bodies undergo major physiological changes.  They cease to be able to digest food and lose the protective slime layer on their skin as their immune systems fail.  With no defenses, fungus attacks their bodies.   The mycelia begin consuming Karen's beloved humpies until, after spawning it eventually consumes all but their skeletons.  Thus ends the cycle for this generation of pink salmon.  Ah, but all is not lost.  While this generation has made the ultimate sacrifice, their bodies will provide the nutrients that nourish the next generation which will emerge from the gravel next spring.  Meanwhile carcasses dragged into the surrounding old-growth forest by bears, eagles, land otters and other predators will decay and fertilize the adjacent riparian area forest.  It's yet another of nature's ways to assure the spectacle we are witnessing this summer will continue for millennia to come -- as long as (like my friend John McCabe would say) mankind doesn't screw it up.


4 comments:

  1. I confess: I was happy for the rain and cooler temperatures, too.

    Cindi

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  2. We were too, Cindi, but then were happy to see the return of sun yesterday.

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  3. Hi, I'm your newest follower. I'm friends with Cindi and Sus but live in Nanaimo, BC. In Nanaimo salmon travel up the Milestone Creek which meanders through Bowen Park. Well, it meanders in the summer but rushes and gushes and floods in early spring! Watching the salmon struggle so hard each year awes and inspires us.
    Thanks for your amazing photos. I'm eager to read some earlier posts. Have a great week. Carole

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  4. Thanks for joining, Carole. These salmon never cease to amaze us. I just returned from a walk further upstream in our City Creek. First I watched a number of them try unsuccessfully to get over what Karen and I figured was a barrier. Then I walked 100 meters or so above the "barrier" without seeing any. Just as I was turning back I spotted some spawners. With more exploration I discovered more and more were getting past it. Hooray.

    ReplyDelete

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