Standing in an Alaskan river, casting a fly-fishing line into waters teeming with salmon, can lead to unexpected contemplation of the state of contemporary government.

I set out recently for a day’s fishing on Alaska’s celebrated Kenai river during the sockeye salmon run, when millions of fish return from years at sea to spawn on the upper reaches of the state’s rivers and then die. It is one of nature’s great dramas.

So good was the sport that by 11am the fishing day was over, since every member of my party had caught three salmon – the maximum number permitted by the Alaska Department of Fish and Game, which monitors the number of sockeye entering the Kenai daily, and adjusts catch limits accordingly. It was just my bad luck that 24 hours later it raised the limit to six fish.