AUGUST 5, 2016--On August 1, R/V Auklet skipper David Janka went ashore in Snug Harbor, Alaska, to take several photos of Mearns Rock, including this one, while motoring back out into Knight Island Passage. David has voluntarily visited the site on various occasions during the past years.

Alan Mearns has been monitoring the boom and bust cycles of marine life on a large boulder—nicknamed "Mearns Rock"—that was oiled but not cleaned after the Exxon Valdez oil spill. What he and OR&R colleague Gary Shigenaka have observed on that rock and elsewhere in Prince William Sound has revealed large natural swings in the numbers of mussels, seaweeds, and barnacles, changes which are unrelated to the oil spill as they were occurring even in areas untouched by the spill.

It has been 27 years since the Exxon Valdez oil spill. Photos have been taken annually of this site starting one year after the spill.

OR&R’s Jeff Lankford and Alan Mearns compared this photo to the 25 others. Most striking is the density and pattern of mussels on today's photo match only one other: 1993. That is, conspicuous life on the rock this year is organized in a pattern that last occurred 23 years ago. Here and at the other sites this year, the cover of rockweed has declined greatly; visible are patches of mussels and barnacles.

These are all sheltered or very sheltered rocky sites. Most long-term intertidal monitoring research on this coast is done at outer wave-exposed shorelines, so this series, in more "oil-sensitive" environment, may be unique. The series underscores that there is both inter-annual and now inter-decadal variability on these shores, and probably many others if anyone bothered to look.

Many thanks to David Janka and others who have volunteered their time to visit and photograph the NOAA long-term monitoring sites.

For further information, contact Alan.Mearns@noaa.gov.

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