Eelgrass Wasting Disease: a Contributor to Decline in the San Juan Islands?
Presentation Abstract
Understanding the possible reasons for eelgrass decline is especially important considering the importance of seagrasses as essential marine habitat and potential for mitigation of climate impacts. Eelgrass wasting disease of Zostera marina caused by the protist Labyrinthula zosterae presents as necrotic, black-edged lesions on eelgrass leaves and can destroy seagrass beds. This disease devastated Atlantic Z. marina beds in the 1930s and is currently common in the San Juan Archipelago. The prevalence of eelgrass wasting disease in the field varies over space and time, from nearly absent in some sites to almost 100% in other sites during its peak during the summer. Our 11 sites surveyed from 2012-2015 around the San Juan Islands show site-specific patterns of disease prevalence and severity over time but an overall increase in wasting disease prevalence between August 2013 and 2015. A four-month time series of surveys in 2015 shows the annual pattern of wasting disease outbreak between May and August. Furthermore, host demography influenced disease patterns, where the oldest, longest, and most dense beds are the most susceptible to disease. Further surveys coupled with laboratory and mesocosm experiments will investigate what local and regional factors facilitate eelgrass wasting disease in the San Juan Islands and its role in seagrass decline.
Session Title
Kelp and Eelgrass
Conference Track
Habitat
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Location
2016SSEC
Type of Presentation
Oral
Genre/Form
presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Zostera marina--Diseases and pests--Monitoring--Washington (State)--San Juan Islands
Geographic Coverage
San Juan Islands (Wash.); Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Eelgrass Wasting Disease: a Contributor to Decline in the San Juan Islands?
2016SSEC
Understanding the possible reasons for eelgrass decline is especially important considering the importance of seagrasses as essential marine habitat and potential for mitigation of climate impacts. Eelgrass wasting disease of Zostera marina caused by the protist Labyrinthula zosterae presents as necrotic, black-edged lesions on eelgrass leaves and can destroy seagrass beds. This disease devastated Atlantic Z. marina beds in the 1930s and is currently common in the San Juan Archipelago. The prevalence of eelgrass wasting disease in the field varies over space and time, from nearly absent in some sites to almost 100% in other sites during its peak during the summer. Our 11 sites surveyed from 2012-2015 around the San Juan Islands show site-specific patterns of disease prevalence and severity over time but an overall increase in wasting disease prevalence between August 2013 and 2015. A four-month time series of surveys in 2015 shows the annual pattern of wasting disease outbreak between May and August. Furthermore, host demography influenced disease patterns, where the oldest, longest, and most dense beds are the most susceptible to disease. Further surveys coupled with laboratory and mesocosm experiments will investigate what local and regional factors facilitate eelgrass wasting disease in the San Juan Islands and its role in seagrass decline.
