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Table 1 General characteristics of the study reservoirs, water quality data recorded during sampling and sample sizes for R. auricularia and L. stagnalis (ranges followed by means in parentheses).

From: Larval trematode communities in Radix auricularia and Lymnaea stagnalis in a reservoir system of the Ruhr River

   Baldeneysee Hengsteysee Harkortsee Kemnader See
Reservoir data Construction (year) 1931 - 1933 1927-1929 1931 1979
  Length (km) 7.8 4.2 3.2 3.0
  Width (m) 355 300 335 420
  Surface area (ha) 264 136 137 125
  Mean depth (m) 3.1 2.0 2.2 2.4
  Mass development of E. nuttallii - + + +
Water quality data Dissolved oxygen concentration (mg/L) 4.45-11.07 (8.09) 9.1-16.35 (11.07) 8.08-11.02 (9.56) 7.24-8.36 (7.87)
  pH 7.1-7.8 7.3-8.7 7.5-7.8 7.3-7.6
   (7.4) (7.8) (7.6) (7.5)
  Conductivity (μS/cm) 390-615 341-478 438-483 415-658
   (505) (406) (461) (527)
  Temperature (°C) 9.8-18.2 9.3-18.2 13-18.6 9.9-15.6
   (15.0) (14.2) (15.8) (13.9)
Snail data Radix auricularia     
  Total no. of snails (pooled samples) 169 195 22 44
  Mean shell height (mm) 15.6 ± 3.5 19.1 ± 3.5 11.9 ± 4.9 17.2 ± 5.1
  No. of distinct samples used (no. of snails) 4 (n = 137)a 4 (n = 166)b 1 (n = 20)c  
  Lymnaea stagnalis     
  Total no. of snails (pooled samples) 135 11 23 16
  Mean shell height (mm) 36.3 ± 8.9 31.3 ± 8.9 38.9 ± 8.7 34.3 ± 14.4
  No. of distinct samples used (no. of snails) 3 (n = 110)d   1 (n = 22)e  
Bird data Fulica atra > 60/80-100 > 100 > 100 > 50
  Anas platyrhynchos 15/20/50 + + +
  Cygnus olor 2/6/30 40 2 3
  Phalacrocorax carbo 6 5 +  
  Larus ridibundus 10 + + > 40
  Branta canadensis    + 20
  Alopochen aegyptiacus     2
  Podiceps cristatus    + 2
  Tachybaptus ruficollis 1    
  Ardea cinerea     1
  1. Bird observations (counts where possible) were carried out on 20.11.2009 (multiple numbers represent counts at different sampling sites within a reservoir; see maps and photos in Additional file 1)
  2. a Sampling sites coded B1, B3a, B3b and B6;bSites coded He1, He2, He3a and He6a;cSite Ha1;dSites B1, B3a and B4;eSite Ha1 (see maps in Additional file 1);+ present but not counted.