Table 1. Sampling locations, salinity and sample size for assessing spatial variance in abundance and prevalence.

Area		Location		Geograph.coordinates		Sampling date		Salinity (psu)		N		% leaves with lesions		% pos. cult. from leaves with lesions
Langeness, Wadden Sea, Germany		Langeness North		N 54.6396 E 08.5781		22.07.12		>30		20		0		No data
		Langeness Creek*		N 54.6320 E 08.5440		28.06.11		>30		20		13		No data
Hooge, Wadden Sea, Germany		Hooge-NW		N 54.5700 E 08.5180		23.07.12		>30		20		0		No data
		Hooge Creek		N 54.5723 E 08.5240		23.07.12		>30		20		0		No data
Amrum, Wadden Sea Germany		Kniepsand Bay		N 54.6203 E 08.3970		20.07.12		>30		20		0		No data
		Amrum-NW		N 54.6960 E 08.3400		19.07.12		>30		20		0		No data
Pellworm, Wadden Sea, Germany		Pellworm		N 54.5504 E 08.5990		26.07.12		>30		20		0		No data
Dagebüll, Wadden Sea, Germany		Dagebüll		N 54.7212 E 08.7051		24.07.12		>30		20		0		No data
Sylt, Wadden Sea, Germany		Puan Klent		N 54.0798 E 08.2960		18.07.12		>30		20		2		No data
		Tonnenleger Bay		N 55.0258 E 08.4323		17.07.12		>30		20		0		No data
		Ellenbogen Creek		N 55.0410 E 08.4130		04.07.11		>30		20		40		42.86
Limfjord, Denmark		Lemvik*		N 56.6300 E 08.2961		28.05.11		>30		19		58		100.00
Skagerrak, Norway		Sandspollen*		N 59.6657 E 10.5869		10.05.10		20–25		21		57		100.00
Åbyfjord, Sweden		Fiskebäckvik*		N 58.3362 E 11.4078		01.06.11		20–25		18		No data		11.11
Gullmarsfjord, Sweden	Bredvik+Snäckebacke-bukten		N 58.1987 E 11.3244		03.07.11		20–30		20		No data		No data
	Kungälv		N 57.5405 E 11.4083		04.07.11		6–14		20		No data		No data
Flensburg Fjord, Germany	Wackerballig*		N 54.7557 E 09.8668		12.07.11		15–17		19		80		100.00
Kiel Fjord, Germany	Falckenstein		N 54.3954 E 10.1935		15.07.11		15–17		20		95		100.00
Faro lagoon, Portugal	Ilha Culatra		N 37.0005 W 07.4921		05.08.11		36		20		No data		No data

The percentage of Zostera marina plants with lesions and successful Labyrinthula isolations are shown where available,

^* = subset of 5 populations chosen for methods comparison.