We've come to fish, film, take photographs and enjoy the pleasure of each other's company. One of Swedish Lapland's pristine rivers is the perfect setting for the occasion. The 120-km trip carries us on the current through scenery that changes every day; from treeless high fell country into coniferous woodlands, via rushing rapids and across mighty lakes. It is a huge ecosystem, and its main artery, the river, has a great impact on me. Probably because it embodies a primal, cleansing force, something that is constantly changing, yet enduring. Here and now, and for all foreseeable time, it is a powerful, life-giving force. My own life is brief; but in the company of the river and the emotions and meaning it engenders, I am given a privileged glimpse of eternity.

For tens of thousands of years, through the eyes of the individual, humanity has always had direct contact with nature and all that lives and grows. All that gives us life comes from the delicate blue-green shell that covers our planet. Since 2008, more people have lived in cities than in rural areas; for the first time in human history, for the vast majority, direct contact with our origins, the planet and its biomass has been broken.

Nowadays, I appreciate the trip more than the fishing. My thoughts escape down narrow alleys and out across open fields. I realize that those of us who are regularly active in environments such as this have more to teach others than just fishing and paddling techniques. Many of the guests come from some of the world's most urbanized places. Here, they gain valuable insight into how to build new ecosystems where they live, so that their cities have less impact on the surrounding biomass, becoming organisms that produce their own food and oxygen, thereby resulting in better quality of life, less stress and better health. Such lessons can add a whole new mental dimension to the guests' trips. In short, new ideas about life in the city for generations to come. Unquestionably, these untamed rivers can give us invaluable insights.

We camp for the night on the shores of the Upper Kaitum Lake before paddling down Tjirtjamströmmarna. These are legendary grayling waters. Besides numerous large grayling, we land many huge pike near a quiet pool between the currents. Big pike, 5 to7 kg, and then even bigger pike that lurk in the depths and come up to take the bait. Where the water is so crystal-clear that we can see all that is taking place, the excitement is almost dizzying. But the largest of these beasts outwit us, refusing to be caught. The weather is with us. But even if it takes a turn for the worse, we can crawl into the tent or brace ourselves for the challenge of inclement weather that is implicit in outdoor living and rafting and canoe trips.

On our second night we stop at the Tjuonajokk fishing camp. Owner Ingemar Kristell speaks of his work to manage sustainable fishing for grayling and salmon trout in the swift waters near the camp. That evening we enjoy a fantastic meal in the lounge, and then, aided by candlelight and headlamps, we plan our onward journey. The following day's fishing on Taivekströmmen is the ultimate aquatic experience. An incredible effort to develop sustainable fishing in these waters has paid off. We paddle onward to the secret haunts of the big salmon trout.

First, we must pass the "big and little falls". In some places, the low water level makes it a little easier to navigate the rapids, but tougher in others, where the water is compressed between huge boulders and rocks. Bypassing the big falls requires a portage. The little falls, which is more like a whitewater chicane with occasional protruding boulders, looks navigable. We let Janne the cameraman go ashore and we take the opportunity to reconnoitre the rapids. "Head for the first drop in the middle, keep to the left, paddle hard, and then stay to the right. Let's go!" A massive adrenalin rush. Adults squealing like children. Everything goes according to plan this time. Chance always plays a big part. We could have taken an involuntary swim for a couple of hundred metres, and then spent the rest of the day sorting out our gear. This time, we stayed dry.

It's a magical evening, and a night with the salmon trout awaits. Bends in the river, carved by time since the Ice Age.  The deep outer curves have been bored out over thousands of years, and there are powerful midstream back eddies. The rapids are turbulent, with huge boulders just beneath the surface. Hollows are resting places where the fish lie and feed. This is where they're lurking. Mats wades out quietly before the evening mist descends. With a black streamer, he lands several beautiful fish in the 2-5 kg range. Micke and Janne, camera at the ready, fight a big salmon trout on the neck of the rapids. It manages to evade them and Micke makes a frantic dash over slippery rocks to make it down to the next calm pool. Finally, it surrenders, allowing itself to be reeled in toward the shore. It's a fine fish, with a hooked jaw, weighing in at about 4 kg. Amazing. And, we've caught the whole thing on film.

There are more days like this ahead and the fishing is still incredible, even though the average weights are somewhat lower. Campfires and restful nights in the tent. Smoked fish is our late-night snack.  Faces are aglow from the generous subarctic sun that beams down from an August sky. We are gratefully aware of the luxury of it all. Images, stories and film will allow us to share a sense of it. However, we're on assignment, and our task is not only to relate this fabulous experience, but to spread the word about the role of the grayling and the salmon trout in the ecosystem and of the importance of managing sport fishing sustainably.  We must speak of the uniqueness of this vast freshwater resource and place it in the context of the scarcity of total global supply.

Globally, there are several processes that are decisive for the continuation of life as we know it. Pollination by insects, photosynthesis, the compostation process, thriving forests and the water cycle. Fishing and paddling on an untamed river gives us deep insight into all of these processes; it is an activity that can provide the basis for greater knowledge of life itself and how we can preserve it, in the microcosm and globally.

The pride of Sweden, the National Rivers, are in the north

Sweden has four protected national rivers: the Kalix, Torne, Pite and Ume/Vindel Rivers. These pristine river environments constitute rich ecosystems with incomparable biodiversity and production. Each of them is a unique biotope. All of them offer dramatic experiences of beauty, superb recreation and top-class fishing. These are priceless values that must be preserved.