LRB does salmon.
Most farmed salmon tastes horrible because caged fish have no opportunity for active swimming. Fed on high-fat pellets full of artificial colour – the pinkness of a wild salmon’s flesh comes from the amphipods and krill it eats during its time at sea – the cooped up salmon simply put on weight without distributing the fat around their bodies. A wild sea-run salmon, by contrast, prepares itself for the journey home by storing fat reserves across its muscles,
connective tissues and under the skin, from where it will draw the energy to sustain it during the task ahead. As soon as it smells fresh water again, an adult salmon will stop feeding, devoting itself solely to the rigours of the voyage, its body beginning its final transformation, as its immune system shuts down to conserve energy, its skin starts to lose its silvery sheen, and (in the case of the male) a rush of hormones prompts the lower jaw to change shape, curving into an aggressive-looking underbite known as a ‘kype’, a jutting scimitar used for fending off other males in the spawning grounds upstream.


The journey can take many months, however, and as the starving returnees battle against the freshwater currents, their fuel reserves deplete rapidly, consumed by the effort of the journey as well as by the production of eggs (by the females) and milt (by the males), so now they must rely on bursts of adrenalin to scale the near vertical ascents. The physical cost of homecoming is enormous, and those that do make it home to spawn arrive in a terrible state, weak, exhausted and already dying from disease and starvation, so the effort of mating, described by Shelton with an Attenboroughesque attentiveness – ‘the quivering displays of the sailor home from the sea bring the hen to arching orgasm’ – is often their final act. Shelton coolly describes the lingering death of a spawned-out male, now known as a ‘kelt’ – the last of its names – lying in ‘the shallow tail of a pool’, with its arteries blocked and muscles wasted, its broken skin scarred by bacterial infections, as it slowly drowns in the water that seeps into its wounds. The decay that follows serves to replenish the river with phosphates and nutrients that in a few months’ time will help sustain the hatched young that emerge from the redds, buoyant and vulnerable in the shallow water, until they, too, are ready to head downstream on the first stage of ‘their great adventure’, as Shelton calls this vast oceanic circumnavigation that will end, as do all great journeys, in the place it began.