F.R. WANLESS AND R. HUNTER 



summer Murray &Pullar(1910). From late autumn to the spring the 

 loch is the same temperature throughout, with progressive develop- 

 ment of stratified conditions from May to the following autumn. The 

 temperature range in midsummer is typically 14.5°C at the surface to 

 5.5°C at 220 m (Mackal & Love, 1969; Murray & Pullar, 1910). 



Maitland (1981) gives a detailed account of human activities 

 which influence the environmental parameters inherent in scientific 

 studies effecting Loch Ness. The loch is relatively unpolluted despite 

 arable, tourist and urban influences. The Scottish Environmental 

 Protection Agency has supplied details of sewerage inputs to Loch 

 Ness which indicate that there are seven direct septic tank inputs 

 from small communities or hotels and tourist attractions, only two of 

 which have monitored flows. Another septic tank inflow enters 

 Loch Ness indirectly via the River Moriston. There are two activated 

 sludge plants for full biological treatment, one at Drumnadrochit 

 and another at Fort Augustus. When maximum flow is reached, 

 sewerage by-passes the treatment plant and discharges untreated 

 into the water course. Seasonal information on the loading variation 

 was not available. However, Drumnadrochit and Fort Augustus are 

 known to frequently breach their consent limits. The water regime of 

 Loch Ness is affected directly by an hydro-electric pump storage 

 scheme based at Foyers and indirectly by four more in the catchment 

 area. These influences may have an effect on the flora and fauna of 

 Loch Ness. 



NEMATODE FAUNA 



So far as is known the only study of nematodes from freshwater 

 lakes of the United Kingdom is that of Martin et al., (1993) who 

 published a full listing of macrobenthic and meiofaunal species from 

 profundal sediments of both Loch Ness and Morar. Their list of 

 nematodes from Loch Ness profundal cores (> 200 m) although not 

 exhaustive includes Ironus temiicaudatus de Man, Tripyla glomerans 

 grp, Tobrilus gracilis grp, Tobrilus cf. pellucidus and Dorylaimid 

 'A'. Additional species listed (Eumonhystera filiformis grp, 

 Eumonhystera cf. longicaudatula, Ethmolaimus pratensis grp, 

 Aphanolaimus sp. and Dorylaimus cf. stagnalis) were collected at 

 lesser depths such as 50-170 m. 



In addition Coles (1996) records Chromadorita tenuis Schneider, 

 1906 and Aphanolaimus ? aquaticus Daday, 1894 from 'trickle of 

 freshwater spring from beside footpath from Goyes Hotel, Foyers 

 Harbour, Loch Ness, Scotland'. 



MATERIAL AND METHODS 



Sampling and fixation 



Profundal sampling: cores were taken with a Bowers and Connolly 

 Multicorer deployed from the research vessel Seol Mara. This 

 device takes four core tubes (each of 5.9 cm diameter giving a core 

 surface area of 27.34 cm 2 ), allowing sediments to be recovered 

 without disturbing the sediment water interface. 



Sediments were sampled at four stations: Fort Augustus Bay, 

 Deep South Basin, Foyers Plateau and Deep North Basin covering a 

 range of depths between 91 and 211 m (Fig. 1, Table 1). At each 

 station sampling was concentrated within approximately 10-20 m : 

 between 10— 13th July 1993, allowing for boat drift. Eight cores 

 were collected from each station except for the Deep North Basin 

 where only four cores were taken because of poor weather conditi- 

 ons. Of the eight cores collected six were used for faunal analysis; of 

 these five were sectioned into two, one centimeter layers. One was 

 sectioned into five one centimeter layers i.e. 0-1 cm, 1-2 cm, 2-3 

 cm, 3—4 and 4—5 cm. The seventh core was used to take redox 

 potential readings immediately on recovery. The top two centimeters 

 of the remaining core was placed in a cold box for carbon content 

 analysis. 



River sampling: sediments were collected by hand with a coring 

 tube of the same dimensions as used for collecting profundal sam- 

 ples. The cores were sectioned as above. Three stations i.e. Rivers 

 Oich, Foyers and Moriston were selected by surveying the area for 

 soft sediment similar in grain size to the profundal samples where 

 core tubes could used with ease. Samples were then taken randomly 

 within an area of 10 m 2 . All samples were sublittoral ranging from 

 0.08-0.39 m depth. Eighteen cores, six from each station were 

 collected from 7-8th August 1994. 



After slicing, all samples were immediately fixed using 8% 

 formaldehyde, at ambient temperature, giving a final dilution of 4% 

 after mixing. A trace of rose bengal was added to the fixative to 

 temporarily stain the nematodes, thus making them easier to see 

 when counting and sorting. 



In addition to the stations listed in Table 1, four sub-littoral 

 qualitative cores were taken from a sandy beach at Borlum Bay, Fort 

 Augustus (NH 085 385) on 22 July 1992 from depths of 0.10-0.38 

 m. Some of the nematode species found did not reoccur during the 

 1992-93 surveys, so we have taken this opportunity to include them 

 in this paper. They are identified in the descriptions as Borlum Bay 



Table 1 Summary of sampling stations, core depths and sediment characteristics. 



Station 



Core 



No's 



Position 



Date 



Depth 

 (m) 



Sediment 



Fort Augustus Bay (FA) 



2-7 



57"08.80'N4"39.45'W 10/7/93 91-105 



Deep South Basin (DSB) 



8-13 



57°12.55'N4°34.55- 



W 



11 + 12/7/93 



194-210 



Foyers Plateau (FP) 



14-19 



57"15.80'N4°29.60" 



W 



12+13/7/93 



150-161 



Deep North Basin (DNB) 



20,22 



57°16.40'N4°29.10' 



W 



13/7/93 



211 211 



River Oich (RO) 



31.32 



NH 094 382 





7/8/94 



0.31 





33,34 



NH 094 382 





7/8/94 



0.20 





35 



NH 094 382 





7/8/94 



0.33 





36 



NH 094 382 





7/8/94 



0.17 



River Foyers (RF) 



40^15 



NH211 495 





7/8/94 



0.14-0.39 



River Moriston (RM) 



50 



NH 211 495 





8/8/94 



0.15 



(account of full data set 



51,52 



NH 211 495 





8/8/94 



0.100.08 



in prep.) 



53 



NH 211 495 





8/8/94 



0.20 





54 



NH 211 495 





8/8/94 



0.15 





55 



NH211 495 





8/8/94 



0.16 



Organic matter (OM) floe, occasionally ferrugineous mixed with 



grey siliceous sand 

 As above but with slight sulphurous smell 

 As above 

 As above 



Sublittoral. River mouth. Algae and OM on surface, coarse sand below 

 Small stones and gravel 

 Coarse sand and small pebbles 

 Coarse sand 

 Stagnant sublittoral. 50 m from river mouth. OM and grey siliceous 



sand containing black streaks. Strong sulphurous smell 

 100 m from river mouth Sand between boulders 

 Coarse sand small pebbles 

 Sand and gravel, some pebbles 

 Coarse sand 

 Sand and gravel 



