Ocean Outbreak by Drew Harvell

Author:Drew Harvell
Language: eng
Format: epub
ISBN: 9780520296978
Publisher: University of California Press

Figure 10. Mortality of the ochre star in Bamfield, British Columbia. Photo by Drew Harvell.

My brain was in overdrive trying to detect every clue to the cause and any patterns driven by variation in the environment. Was there any new evidence to support my hypothesis that the die-off was caused by an infectious, transmissible agent, as opposed to a low-oxygen or strange pollution event? The unexpected better survival in the intertidal at a site where all the subtidal stars of the same species were dead was a big clue, but what did it tell us about why the underwater zone was so lethal? Were the intertidal stars escaping a new lethal pollutant carried down the Duwamish River—which was on the edge of an EPA Superfund site—or was the freshwater a route carrying in a new infectious agent from land? If an infectious agent was the cause, why was it suddenly breaking out? Why was it continuing into the winter? Why was it more lethal for subtidal stars? Was the agent killing other animals? How was it transmitted—was it conveyed in their food? How many species of star were affected? Another question with personal significance rapidly emerged: were the starfish in the San Juan Islands sick as well?

That night at Alki Beach on December 17, 2013, is embedded in my mind as the moment when the real craziness began for us, when we realized that starfish mortality was spreading rapidly and cropping up in unpredictable places, and we began to worry about our local populations of starfish. That same week, Laura James and Ben Miner (of Western Washington University) saw many ochre, mottled, and sunflower stars dying in deeper water on a dive near Mukilteo, Washington. Deaths were reported in lower Puget Sound; increased mortality was reported by Steve Fradkin from Olympic National Park; and reports kept coming in from Melissa Miner and Pete Raimondi’s monitoring program in California and the Vancouver Aquarium’s network. Shaken by the carnage at Alki, news of these new mortalities, and the observations from Monterey of the wide species range being affected, I returned to my home in Friday Harbor in December worried that starfish in the San Juan Islands would also sicken.

Morgan Eisenlord, my assistant, was still in Friday Harbor, and she was as determined as I to crack the mystery of what was killing the stars. A week after our work at Alki Beach, on that same low tide series in December, she and I went north to check the status of the stars in Friday Harbor. The low tide was after 10:00 pm, but it was a relatively warm, still winter night, about forty degrees with no wind or rain. We started with an easy place as the tide was dropping. We walked down the pier at the lab docks and shone our lights on the pilings, a little nervous about what we might see. It was low tide, so the pilings were uncovered and we could immediately see about six sunflower stars, each one almost as large as a manhole cover, lurking on pilings just at the water line.

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