FRESHWATER NEMATODES FROM LOCH NESS 



R. Ness 



200m contour 



Farigaig 



R. Foyers 

 200m contour 



Direction of flow 



1 . River Oich (RO) 



2. Fort Augustus Bay (FA) 



3. River Moriston (RM) 



4. Deep South Basin (DSB) 



5. River Foyers (RF) 



6. Foyers Plateau (FP) 



7. Deep North Basin (DNB) 



** Activated sludge treatment 

 * Significant septic tank input 



R. Tarff 

 Fig. 1 Map of Loch Ness showing sampling stations. 



(1992 collection). Also, they have not been included in the ecologi- 

 cal part of this study which is based entirely on the 1992-93 

 samples. 



Extraction and slide preparation 



Nematodes were extracted by the Ludox centrifugation-floatation 

 technique (Persmark et al., 1 992). However, after extracting the first 

 core it was found that the nematodes were still obscured by large 



amounts of organic matter of very similar density to that of the 

 nematodes. In order to reduce sample sorting time, it was decided to 

 subsample the remaining 1 cm core slices using the 'Asko sample 

 splitter' Elmgren (1973). Two hundred nematodes were picked out 

 from each core; if less than 200 nematodes were present in the first 

 subsample, further subsamples were extracted until the required 

 number was found. Extracted nematodes were then dehydrated to 

 glycerine by the Seinhorst method (Seinhorst 1962). 



