Monday, 13 February 2017

Dolphins and Nessies

A recent BBC news item tells us that the populations of three dolphin species off the Scottish west coast are now at record levels since their surveys began in 1994. The key quote for me is this:

Dolphins are known as indicator species. They are a top predator, and if your top predator in an eco-system is doing well then that's a good sign that everything else in the eco-system is going well.

What has this to do with the Loch Ness Monster you may ask? Well, it has been one of my arguments that the decline in fish stocks around the Scottish coastline has also had an impact on the ecosystem of Loch Ness. Less fish means less Nessies and less Nessies means less sightings means less photographic opportunities. 

The question of biomass in Loch Ness has always been a qualified affair to me. When the various fish counts were done in recent decades, there was always the chance that these figures were historic lows. In other words, arguing that there is not enough food in Loch Ness for a number of large predators, even though it could be challenged, could only ever apply to the loch at that point in time.

It did not address biomass in the 1930s when reports began to ramp up, let alone 1940s through to the 1960s before environmental changes began to impact the loch. Undoubtedly there were more fish stocks back in those days and the whole food question becomes opaque for those periods.

But the main point is that the eco-system appears to be reviving and the hope is that these enigmatic creatures will begin to increase in numbers and again break the surface of the loch.

Original article here.

The author can be contacted at


  1. I've got to question your line of reasoning here Roland. How were there 'undoubtedly' more fish stocks in the loch in the 30s and 40s? Seems speculative to me.

    What environmental changes are you referring to?

  2. The Loch contains salmon but do they enter the Loch to breed only? Are the arctic char and salmon populations full year residents? This always puzzled me. It seems eels have healthy numbers in the water.

    1. There is also the run of the young out of the loch system, but that is obviously in the opposite direction.

      Some salmon will stay in the loch system after spawning and die. It is not clear to me how many return to the sea.

      Nobody knows how many eel reside in Loch Ness. The number given in the 60s was millions.

  3. Do we know if species outside of, but close to, the loch give any indication of the conditions with the loch itself? Or is Loch Ness a relatively closed eco system?

    1. The trout and salmon runs would be the biggest factor. These runs have been known to be on the decline for a long time. Since water flows from the loch to the sea, we do not expect much else to impact the local ecosystem. The other factors that have been suggested in the past were pollution and acid rain.

      Global warming is the new kid on the block, but when it was global freezing back in the 1970s, I don't recall reading that as a factor in anything.

  4. Overfishing by whom ?

    Is commercial fishing allowed on the loch these days?
    If not, it's just the lone Ted Holidays of this world on boat or shore angling for a bite. On a loch the size of Ness, that's not going to make a dent in fish stocks.

    According to N. Witchell, There were pro eel catchers in the past at the loch using multiple hooked long lines.

    1. Overfishing outside the loch, I don't know about in the loch, maybe or maybe not. The point is overfishing outside impacts the salmon and trout at least.

  5. We attribute global warming to the increase of dolphin sighting in Scottish waters.