THE salmon is often described as the "king of fish" – and rightly so, for they are magnificent.

But when it comes to ecological importance to our rivers, I reckon the humble minnow has every justification as being a worthy rival to the piscine throne.

This was brought home to me recently when I went on an underwater exploration of the River Devon.

It was an inauspicious start because after donning my snorkel and mask, and then wading into the river to find deeper water, I became inextricably stuck in deep, soft mud.

There was a momentary panic, for my right leg was so entombed in clawing mud that no amount of heaving could pull me free.

Keep calm, I thought, so I lay on my back in the shallow water to spread the body weight, and after some considerable effort, was eventually able to wriggle free.

I turned over and floundered into deeper water, which gave me a chance to examine through my face mask the muddy riverbed that had just trapped me.

This silt was rich in organic matter and strings of bubbles rose from little holes on the river bed, which was escaping gas from the vegetative decomposition process.

Compared to the sea, the visibility was poor, but still good enough to see several inches ahead.

I glided over to a dead tree that had tumbled into the river, and in among the submerged branches and entanglement of twigs and waterlogged wood, a huge shoal of minnows flickered.

Just as how a rocky oceanic reef is an oasis of life, then so too are these fallen trees in rivers, providing shelter for fish and invertebrates.

Furthermore, they help to slow the water flow in times of flood, providing additional protection for river creatures.

It was also a vivid illustration of how beavers boost our rivers, for the trees they fell into the water create rich new habitat that benefit all kinds of animals, including trout and young salmon.

The large numbers of minnows around me was astonishing, and when I rested my hand on the soft river bottom, a swarm of the fish darted about excitedly, feeding on the disturbed detritus and nibbling at my splayed fingers.

It was like having a fish manicure and it was a strangely relaxing experience. I could also feel minnows gently pecking my bare calves.

For kingfishers and goosanders, as well as many other creatures, these minnows provide vital food, and are an ecological keystone to the productivity of the river.

I carefully pulled myself back out the water lest I became stuck once more, and sat dripping on the bankside, revelling in the beauty of nature all around me.