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Postscript: Surgeon or Sturgeon?

Reproduced with the permission of the Scottish Naturalist
Copyright: May be used for private research. All other rights reserved


Loch Ness and Morar Project

It would be churlish, in view of all the recent additional information, to allow the sixtieth anniversary of the naming of the Loch Ness 'Monster' (Anon., 1933 - attributed to Mr. Alex Campbell)  to pass entirely unremarked.  For most people, certainly the majority of the casually interested members of the general public, the famous 'Surgeon's Photograph' of 1934 probably represents their idea of the archetypal Monster.  Certainly this well-known photograph has figured in numerous publications over the past sixty-odd years, and a serious investigation and assessment of the photograph was published in the centenary (1988) volume of the Scottish Naturalist (LeBlond and Collins, 1988).

Acoustic Assessment of Fish Size

One consequence of the introduction of more quantifying acoustic techniques - in situ target strength measurement in particular , was the discovery that the great majority of pelagic fish in Loch Ness belonged to a very small size group, which were not caught prior to the trawling methods recently described (Shine, Martin and Marjoram, 1993).  Therefore there was a tendency to 'scale' large sonar echoes against gill-netted individuals of 20-30 cm, which in reality represented only a small proportion of the population.  This imposes a further revision upon assessment of sonar contacts which are strong in relation to the surrounding fish echoes.

Estimates of 'Monster' Population

Sheldon and Kerr (1972) first attempted estimations of theoretical 'Monster' population density based on fish biomass.  They used the morphoedaphic index (total dissolved solids/mean depth), devised by Ryder (1965), to estimate the fish population.  Lacking genuine Loch Ness information, however, data was used from the northern basin of Loch Lomond.  For Loch Ness, a fish standing stock of between 0.55 and 2.75 kg/ha was calculated, or between 3.135 and 15.675 tonnes in total.

On-site acoustic estimates of resident pelagic fish in Loch Ness now range from 3.1 kg/ha (Shine, Martin and Marjoram, 1993) to 4.23 kg/ha (Kubecka, Duncan and Butterworth, 1993), or between 17 and 24 tonnes in total, as compared to 300

Vol 105, The Scottish Naturalist: Postscript: Surgeon or Sturgeon? p272

to 400 kg/ha in the upper River Thames (current acoustic estimate - Dr. J. Kubecka, pers. comm.).  These estimates exceed those of Sheldon and Kerr, and may be accounted for by allochthonous organic inputs.  Before hopes are raised too high, however, it should be borne in mind that predators upon this biomass should not amount to more than approximately a tenth of the gross weight.  Thus we have available a total of approximately two tonnes of 'Monster', but this two tonnes may not be as great as it at first seems.  For example, it would be equivalent to scarcely half the weight of a 36-ft (13 m) Whale Shark Rhinocodon typus.  In fact, two tonnes divided into an absolute minimum viable population of, say, ten creatures, would give an individual weight of only 200 kg.

In fish terms this could be equivalent to a Sturgeon Acipenser sturio 2.8 m in length (Maitland and Campbell, 1992: 92).  The above pelagic biomass estimates are somewhat academic since they do not include migratory Salmon Salmo salar or Sea Trout Salmo trutta, which may swim too close to the surface or too close inshore to be surveyed efficiently by acoustics.  For the same reason the littoral fish habitat, which is richer than the pelagic, is not included since some of the fish, and all benthic fish e.g. Eels Anguilla anguilla, would be too close to the bottom to be detected.  Nevertheless, it is now scarcely possible to argue a case for a population of resident 'Monster' predators.

Fish the Most Likely Candidates

After dismissing the classic Monster photographs, Shine and Martin (1988) concluded that if, among the many recorded explanations for sighting reports, large unusual creatures were indeed involved, then fish would be the most likely candidates.  This was based upon the facts that Loch Ness, as a proven refuge for cold-water Ice Age relict species, was one of the last places on earth likely to be favoured by reptiles, Jurassic or otherwise.  Since there are no known marine amphibia, these could not, like almost all the other vertebrate inhabitants of the loch, have made their way up the river from the sea.  Finally, any mammals should long ago have advertised their presence while breathing.


The largest aquatic animal to have been recognised in Loch Ness is the Common Seal Phoca vitulina (Williamson, 1988), some of which occasionally enter the loch, presumably in pursuit of migrating Salmon, and could have caused some sighting reports.  Salmon, the largest recorded fish in the loch, migrate inland to spawn but do not feed in fresh-water, and this habit may perhaps provide a clue to another, much larger, possible candidate which could have contributed to the Loch Ness controversy.

Vol 105, The Scottish Naturalist: Postscript: Surgeon or Sturgeon? p273

Resident Predators

A problem with a theoretical population of hitherto unrecorded predatory fish is that fish reproduction, whether by egg-laying or live-bearing, gives rise to relatively large numbers of small juveniles developing independent of parental care.  It seems unlikely that these would have avoided capture by fishing over the years, either by towed lure or from the beach.  They would also have had to evade the netting and trawling programmes described in Shine, Kubecka, Martin and Duncan (1993), let alone decades of illicit Salmon netting. 

It is not inconceivable, however, that along with the Salmon and the Common Seal, Loch Ness might have played host to another visitor.

A Sturgeon?

The possibility of the afore-mentioned Sturgeon actually being responsible for the beginnings of the tradition, and for some sighting reports since then, is quite attractive.  Sturgeons would not necessarily be immediately recognised as fish.  They are very large, have a long upturned snout, and a dorsal fin set well back towards the tail (Figure 1a, 2K) (Gould, 1934: 136).

In 1987 a Sturgeon, eleven feet (3.35 m) long and weighing 900 lbs (408 kg) was found dead, floating in Lake Washington near Seattle, U.S.A., where stories of a 'Monster' had circulated (Albuquerque Journal, 7th November 1987).  No-one would suggest, however, that Sturgeons would even begin to enter the reckoning, against the huge multi-humped manifestations of the 1930s ascribed by Baker (Observer, 26th August 1962), to boat wakes, or to many other reports.  There is no one answer to the question of the Loch Ness Monster.

Sturgeons are cold-water northern hemisphere fish of very large size (up to >3.0 m) and of unusual appearance.  They would be independent of the food resources, since, before entering the loch in order to spawn, they would cease feeding.  Moreover, since Sturgeons are such rare visitors to British rivers, any which did succeed in passing the two weirs on the River Ness would be very unlikely to find mates.  After a lonely vigil off one of the river mouths they would presumably leave again without issue, save, perhaps, for some interesting sighting reports.

Vol 105, The Scottish Naturalist: Postscript: Surgeon or Sturgeon? p275

Gould's Early Investigations

In November 1933 Lt.-Commander R.T. Gould (1934: 30) listened to the account of Mr. John McLeod, who, some 20-30 years previously had seen, at the mouth of the River Moriston beneath the lowest fall, a creature with a "head like an eel and a long tapering tail".  This is how a Sturgeon might appear from above.  Another witness, Miss K. MacDonald, spoke of a "crocodile"-like creature, 6-8 feet long, ascending the River Ness and heading for the Holm Mills weir, in February 1932 (Gould, 1943: 38).  Rather more recently, in 1993, Mrs Marion MacDonald described to the author an experience at the Fort Augustus Abbey harbour.  She saw what she first thought was a log, because of a distinctive 'scaly' bark pattern, but which then developed a wake and moved off to submerge, while she called her family.  After she had sketched her impression (Figure 2, 8K) she was shown an illustration of a Sturgeon's bony plates, and considered the pattern to be reminiscent of what she had seen.


For and Against a Sturgeon

Anyone, of course, can assemble sighting reports to support a pet theory, and this one is brought forward mainly to show that, even in the absence of significant food resources, the largest freshwater fish in existence could possibly have been seen at intervals in Loch Ness.  Given the large number of other causes behind sighting reports (Binns and Bell, 1983; Campbell, 1986), these intervals could be very long indeed.

There is, however, a great deal more to the Loch Ness Monster than scientific probabilities, and the greatest argument against the Sturgeon or, more importantly, against any species of fish, is the long neck reported (Figure 1b, 7K), although such reports are more rare than is generally realised.  It should be borne in mind that the first report of a long neck was when the "nearest approach to a dragon or prehistoric animal" lurched its way across the hot tarmac in front of the Spicer's motor car in July 1933 (Inverness Courier, 4th August 1933).  This unprecedented behaviour has never been reported since.  Prior to this, the beast was usually considered to be an unusual fish; Inverness Courier, 8th October 1868 ("a huge fish"), Northern Chronicle, 27th August 1930 ("a fish.....or whatever it was") and Scottish Daily Express, 9th June 1933 ("a mystery fish").

Errors of Identification

Undoubtedly, some 'long-necked' reports originate from water birds, such as Mr. Alex. Campbell's sighting (Gould, 1934: 111), although this was subsequently revised as the archetypal plesiosaur (Witchell, 1975: 55).  Some large long-necked animals have indeed been seen swimming in the loch.  The author is aware of five

Vol 105, The Scottish Naturalist: Postscript: Surgeon or Sturgeon? p277

instances when such animals have subsequently been identified as swimming deer. On three occasions, photographs were taken (Figure 3).  It has been suggested by Burton (1961: 130-138) that some sightings, including some influential ones, could be due to such errors.

Experiments with Human Perception

It is now well understood that human perception consists of much more than just image, retina and memory.  In contrast to 'hard' evidence, such as photographs, however, it is very difficult to assess sightings evidence because it is not usually possible to stand beside the witness.  An exception to this is if an incident is contrived.

Mr. Richard Frere gives an account (Frere, 1988: 175) of standing at a busy lay-by and, through a little theatrical behaviour, drawing attention to the turbulence caused by some trawler wakes.  Reactions included sightings of various humps, long dark bodies, side flippers, and a thrashing tail.  A drawing produced by a child showed a plesiosaur.

On a less spectacular scale, members of the Project have also stood beside volunteer eye-witnesses, who were asked to observe an object surfacing and submerging.  All were aware that we were contriving the incident, and it therefore seems possible that impressions were inspired less by pre-conceived Loch Ness Monster stereotypes than by concepts of the mechanism in the equipment.  However, the results of this rather 'conservative' experiment (Figure 4, 17K) are of some interest, since 31% of the 36 observers retained impressions at some variance  with the 45 cm straight-sided post they had actually seen at a range of approximately 150 m.

Given that variation exists between image and perception in such prepared observers, it seems likely that individuals, sighting unrecognised objects on Loch Ness, may well have their perceptions influenced by the well-known Monster stereotypes.  It is certainly the case that the wider impression of events, as disseminated and recorded by the media, may bear little relationship to what was actually seen.  For example, in a recent case Miss Edna MacInnes was widely reported as having seen a creature with a "giraffe-like" neck (Aberdeen Press and Journal, 25th June 1993).  When interviewed later she denied this, and stated that she had used the word "giraffe" in the context of conveying the sense of movement which the object made.  Her drawing appears in Figure 5 (12K).

Vol 105, The Scottish Naturalist: Postscript: Surgeon or Sturgeon? p281

Some Conclusions

Burton (1961: 91) suggested that gas such as methane could bring decaying vegetation, perhaps including branches resembling necks, to the surface.  In the main, the Project's work has shown little gas production in deep Loch Ness sediments.  There are two exceptional areas, however; one is a small area in Urquhart Bay, and there is a larger one off Fort Augustus, where great quantities of organic material accumulate and emit gas continuously during the summer.  On one occasion (Figure 6, 19K colour chart), gas was detected from a source as deep as 97 m, which remained active for two weeks.  It seems that vegetable debris, including branches, could break the surface in this particular 'Monster spot'. 

The morals of this story are two-fold.  Firstly, large creatures may plausibly be witnessed in Loch Ness, whether or not science discovers sufficient red-herrings with which to feed them.  On the other hand, the types of creatures suggested by science should not be over-ruled simply because they do not fit all witness perceptions. 

Those who find the author's attempts to modify the status of the very long-necked sightings unsatisfactory, may take comfort from the 'Surgeon's Photograph', standing guard over popular expectations for some sixty years, and confounding any science to take itself too seriously.


Anon.  (1933).  Strange spectacle on Loch Ness.  What was it?  (From a correspondent).  Inverness Courier, 2nd May 1933.

Binns, R. and Bell, R.J.  (1983).  The Loch Ness Mystery Solved.  Shepton Mallet, Somerset:  Open Books.

Burton, M.  (1961).  The Elusive Monster.  London:  Hart Davies.

Campbell, S.  (1986).  The Loch Ness Monster.  The Evidence.  Wellingborough, Northamptonshire:  Aquarian Press.

Frere, R.  (1988).  Loch Ness.  London:  John Murray.

Gould, R.T.  (1934).  The Loch Ness Monster and Others.  London: Geoffrey Bles.

Kubecka, J., Duncan, A. and Butterworth, A.J. (1993).  Large and small organisms detected in the open waters of Loch Ness by dual-beam acoustics.  Scottish Naturalist, 105:  175-193.

Vol 105, The Scottish Naturalist: Postscript: Surgeon or Sturgeon? p282

Leblond, P.H. and Collins, M.J.  (1988).  The Wilson Nessie photograph: a size determination based on physical principles.  Scottish Naturalist, 100: 95-108.

Maitland P.S. and Campbell, R.N.  (1992).  Freshwater Fishes of the British Isles.  New Naturalist Library, No. 75.  London: Harper Collins.

Ryder, R.A.  (1965).  A method for estimating the potential fish production of north-temperate lakes.  Transactions of the American Fisheries Society, 94: 214-218.

Sheldon, R.W. and Kerr, S.R.  (1972).  The population density of Monsters in Loch Ness.  Limnology and Oceanography, 17: 746-798.

Shine, A.J. and Martin, D.S. (1988).  Loch Ness habitats observed by sonar and underwater television.  Scottish Naturalist, 100: 111-199.

Shine, A.J., Martin, D.S. and Marjoram, R.S.  (1993).  Spatial distribution and diurnal migration of the pelagic fish and zooplankton in Loch Ness.  Scottish Naturalist, 105: 195-235.

Williamson, G.R.  (1988).  Seals in Loch Ness.  Scientific Reports of the Whales Research Institute, No. 39 (March 1988).  Tokyo, Japan.

Witchell, N.  (1975).  The Loch Ness Story.  London: Penguin Books.



Received July 1993

Mr. Adrian J. Shine,
Loch Ness and Morar Project,
Loch Ness Centre,
IV3 6TU.





Loch Ness Surgeon or Sturgeon