Gulf of Alaska | Ecosystem Perspectives
Volunteer-driven annual photography documents the range of natural variability of rocky intertidal communities in western Prince William Sound Presenter: Rob Campbell, rcampbell@pwssc.org, Prince William Sound Science Center Alan Mearns , alan.mearns@noaa.gov, noaa
David Janka , info@auklet.com, Auklet Charter Services Brian Robinson , brobinson@usgs.gov, US Geological Survey Scott Pegau , spegau@pwssc.org, Prince William Sound Science Center
This poster presents a 33rd year update of annual repeated photographs of several intertidal sites in western Prince William Sound, Alaska, an area impacted by the March 24, 1989 Exxon Valdez Oil Spill. During the 1990s site photos were part of an intensive annual monitoring program to document recovery from oiling and aggressive clean-up. During the 2000s, 2010s, and into the 2020s, volunteers continued to photo-monitor the sites as time permitted during their other activities in Prince William Sound. The photos are being used to estimate annual changes in percent cover of Rockweed ( Fucus sp .), mussels ( Myt lus trossulus ) and barnacles. Over the past three decades, inter-annual variability of Rockweed cover has largely been asynchronous across sites whereas inter-annual variability in mussel cover has been surprisingly synchronous among four widely separated sites. An unbroken, 33-year continuous annual series of photos from a site in southern Knight Island (Mearns’ Rock) shows interannual Rockweed cover ranging from nearly zero to nearly 100 percent, with peak-to-peak episodes occurring at 3 to 7 year intervals. These and other examples from other sites indicate that inter-annual biological variability needs to be understood and accommodated when evaluating recovery from impacts. Annually-repeated photographs, over several decades, not only offer an economical method for documenting trends but also provides the public with a visually compelling appreciation of natural variability.
Alaska Marine Science Symposium 2023 160
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