Monday, November 16, 2009

Salmon at Kennedy Creek

On Saturday morning we awoke to a deep frost, crusting the grass and roofs with white crystals, cold and still. It was foggy too, with clouds of billowing fog sneaking fingers through the neighborhood trees. I sat inside by the big window, in my warm jammies, reluctant to even think of going outside. But my friend JoAnna and I had made plans to go to Kennedy creek, to see the annual flood of Chum salmon making their way upstream to spawn. This was an invitation from nature not to be refused.

Kennedy creek is a beautiful healthy creek that flows out of the Black Hills in northwestern Thurston county. If you head northwest on highway 101 towards Shelton, about ten miles out of Olympia, the highway drops down to sea level and you cross the Kennedy creek estuary. I have spent many happy hours at this estuary, counting shorebirds and watching the tide flow in and out.

On Saturday, the tide was coming in strongly, a new moon high tide swollen with the recent rains. This is the kind of flow that triggers the Chum to go up the river. Here in November, this is their month: all month long they will run the river of their birth, seeking places to spawn.

So here in this amazing place, JoAnna and I found a quiet place by the rain-swollen creek and settled in to watch. At first we saw nothing and thought we'd missed the fish. But as we quietly settled in, suddenly we heard the wild splashing of nearby salmon. The splashing, churning, chasing behavior is usually done by the males, in perhaps a territorial or dominance display. I never see the females do it; JoAnna and I remarked to each other how females in general have better things to do.

Among salmon, there is sexual dimorphism: the females are small and more gray. The males are larger, much more brightly colored in mottled green and red, and among the Chum, the spawning males develop an elongated snout and enlarged teeth, which give them the look of fighting dogs. Hence their other name: Dog salmon.

The name of Chum comes from the Chinook jargon language "Tzum", which means mixed colors, spots or stripes. This certainly fits the Chum in this fall season.

The females look for likely gravel beds in which to make their salmon nest or redd. The gravel must be clean of sediments, well-oxygenated, and protected from the main stream of the creek, to avoid washing out in flood times. This sort of real estate is at a premium in Kennedy creek; where the females find it, they congregate, along with a swarm of males all eager to participate in fertilization.

In general, there is a dominant male who guards the female and sticks close. He often chases off other intruding males - hence the splashy displays. He wins by virtue of his size and ferocity. When his female completes her redd and lays her eggs, it is his sperm that will fertilize them.

Other smaller males, called jacks, cannot hope to win these battles of size and temperament. Their strategy is to lurk in the shallows, making use of their lighter colors to blend into the murky water. When the dominant male has his back turned, chasing off other intruders, the jack sneaks in and fertilizes the eggs. It is strategy that works more often than you might think.

After the eggs are laid, the female is done and she dies. The males hang on a little longer, traveling up and down the stream to look for other fertilization opportunities. Then they, too, die. Sometime in their long journey from ocean to Puget Sound to Kennedy creek estuary, the salmon stop eating. They digest their own stored fat, and later, their own protein to survive just long enough to spawn. As they stop eating, their immune system weakens and their bodies are attacked by a wide variety of pathogens. You can see in the picture, the dead male is a blotchy white-red: the white is a fungus that overwhelms the salmon's immune system.

Along the banks of Kennedy creek, bloated white carcasses of salmon lie. They provide a crucial last service to the ecosystem; in our temperate rain forests, rain washes away a lot of the nutrients. The bodies of salmon fertilize the streams, providing nutrients to all of the forest. The caddisfly larvae in the stream, the young salmon smolts, the nearby threads of fungus, the tree roots all feed from these dying salmon bodies. And when the caddisfly molts into an adult fly, it is the nearby Wilson's warblers who catch them to feed their young, while the young salmon grow up and head out to sea. All these animals carry within themselves the life that was gifted to them by the death of the salmon.

JoAnna and I sit quietly in this frosty morning, looking on this dance of life and death. Overhead, the Bald Eagles lurk in the trees, their high-pitched loony cackle drifting through the lichen-shrouded trees. There is the damp sponge of Earth in fall, the leaves dropping off the trees, the smell of damp and fungus and dying fish, all wrapped around us. And in front of us, in the greatest nature show of all, we watch the last days of these magnificent animals, creating the future in the waters of Kennedy Creek.

Resources: webpage of Kennedy Creek salmon wildlife watching area:

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