Parasites in the northern Wadden Sea: a conservative ecosystem component over 4 decades

Table 1 Parasite species occurring in cockles (Cerastoderma edule) in the late 1960s (Lauckner 1971) and in 2003/2004 (Thieltges and Reise 2006)

Parasite species	Lauckner (1971)	Thieltges and Reise (2006)	Trend
First int. hosts
Gymnophallus choledochus	×	×	=
Labratrema minimus	0	×	+
Monorchis parvus	0	×	+
Second int. host
Himasthla elongata	×	×	=
H. continua	×	×	=
H. interrupta	×	×	=
Renicola roscovita	×	×	=
Psilostomum brevicole	×	×	=
Meiogymnophallus minutus	×	×	–
Gymnophallus gibberosus	×	×	=

0 absent, × present. Trends in infection levels are indicated as follows: + increasing trend, − decreasing trend, = infection levels similar

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