…a blog written by Buglife Saving Sites Officer, Gemma Waters
Loch Ness is impressive on many levels, and certainly on scale, as it is the second largest and the second deepest loch in Scotland. However, it takes the number one spot for holding the most water, nearly 7.5 million cubic metres, which is more water than all the lakes of England and Wales combined! The last comprehensive study of invertebrate life in Loch Ness identified a wealth of invertebrate life, second only in Scotland to Loch Lomond for species richness.
With a maximum depth of 230m, little or no light penetrates to the deep soft sediment of the loch bed. There has been much speculation on what may live in the depths of the murky peat-stained waters. Invertebrates we know can live in this area called the profundal zone – or the abyss – include worms, non-biting midge larvae, snails and mussels.
One rare mussel that finds a home in Loch Ness is the tiny Vulnerable Arctic-alpine Pea Clam (Euglesa conventus). Often smaller than a fingernail, pea clams are a group of freshwater bivalve molluscs, that live in a wide range of wetland habitats. As its name suggest, the Arctic-alpine Pea Clam is a cold-water species, adapted to the cool conditions found in Loch Ness and is dependent on deep glacial lakes for its survival Despite their small size of less than 3mm, they can play an important role in filtering water and recycling nutrients.
Moving to the shallower areas of Loch Ness, particularly on the western shore you can find the most species rich habitats for aquatic invertebrates. This includes groups such as beetles, worms, crustaceans, leeches, stoneflies, snails and flies.
In the shallow bays you can find another invertebrate seeking the cool waters of the loch, the Nationally Scarce Upland Summer Mayfly (Ameletus inopinatus). Amongst the stones and debris of the shoreline, the eggs of the mayfly hatch in the autumn and the larvae grow through the winter months, emerging as adults in May and June. Adults take to the air on shining lace-like wings to display and mate, having only hours or a few days to produce the next generation which will start their lives in the waters of the loch.
Caddisfly larvae also develop in the shallower waters, including several different families of cased caddisflies. The name for these insects is thought to come from Elizabethan street vendors called caddice men who sold braids and fabrics, pinning their ware to their coats. Caddisfly larvae are able to produce silk in which to make protective tubes, covering them in materials they find in their environment such as woody debris, stones, sand and leaves. Often only their heads can be seen protruding, though some species can swim, rowing through the water with their fringed legs. Even small species, called ‘micro-caddis’ that are only a few millimetres long, such as those found in the family Hydroptilidae make these transportable cases.
Whilst Loch Ness feels like a wild and remote location it has not escaped accruing some unwelcome non-native species, often with consequences for native fauna. One species that has flourished in Loch Ness is a North American flatworm Phagocata woodworthi. This international hitchhiker arrived in the 1970s, possibly on the equipment of those seeking the Loch Ness monster, showing the tenacity of this species to survive such a long journey. This flatworm is a predator of other invertebrates and outcompetes the native flatworms of the loch.
So, whilst many visitors will be looking out for the legendry Loch Ness monster, there is a wealth of amazing smaller animals to find but also some less welcome inhabitants that could be viewed as pretty monstrous to our native fauna. Though small, these invertebrates punch above their weight with the critical role they play in maintaining the ecosystem of the world-famous Loch Ness.
Buglife and partners are working to protect Loch Ness and nearby Loch Kemp from a damaging Pumped Storage Hydro scheme. Find out more about the campaign through our Protect the Wildlife of Loch Ness and Loch Kemp web pages.
Main image credit: Loch Ness © Wolfgang Pichler (CC BY-NC-SA 2.0)