Before and after wasting disease in common eelgrass Zostera marina along the French Atlantic coasts: a general overview and first accurate mapping

We examined the original manuscripts of a French national survey conducted in 1933 on the state of common eelgrass Zostera marina beds along the French Atlantic coasts during the period when wasting disease struck the entire North Atlantic population in the 1930s. Based on GIS related techniques and...

Full description

Bibliographic Details
Published in:Diseases of Aquatic Organisms
Main Authors: Godet, L, Fournier, Jonathan, Van Katwijk, M, Olivier, F, Le Mao, Patrick, Retiere, C
Format: Article in Journal/Newspaper
Language:English
Published: Inter-Research 2008
Subjects:
Online Access:https://archimer.ifremer.fr/doc/2008/publication-4294.pdf
https://doi.org/10.3354/dao01897
https://archimer.ifremer.fr/doc/00000/4294/
Description
Summary:We examined the original manuscripts of a French national survey conducted in 1933 on the state of common eelgrass Zostera marina beds along the French Atlantic coasts during the period when wasting disease struck the entire North Atlantic population in the 1930s. Based on GIS related techniques and old sets of aerial photographs, we present the first accurate mapping of the Z. marina beds before wasting disease occurred and assess their spatial recolonization since the 1950s in the Chausey Archipelago (France), which contains large Z. marina beds. The national survey confirmed that the Z. marina beds almost totally disappeared from the French coasts during the 1930s. However, the disease symptoms seem to have begun locally a few years before. On the study site, we found that the Z. marina beds were more than twice as extended than as they are today, and covered both subtidal and intertidal areas. By the 1950s, 20 yr after the onset of the disease, the beds had hardly recolonized, and contrary to the recolonization patterns reported elsewhere in Europe, they were mainly restricted to subtidal areas. The subtidal and intertidal Z. marina beds on the site are now rapidly expanding.