Leaping salmon

Leaping salmon

Wikipedia informs us that the Atlantic salmon (Salmo salar) is found in the northern Atlantic Ocean and in rivers that flow into the north Atlantic.

The salmon’s journey through life from fresh to salt water and back to fresh is not just an aquatic journey, but a terminological one too, as shall be shown.

The salmon spend their early life in fresh water, when the immature salmon are known firstly as alevin, then as fry and finally as parr, this final stage being when the juvenile salmon prepare to migrate to salt water.

When the parr develop into smolt, they begin their trip to the ocean; this occurs mainly between March and June. The length of time that young salmon take before journeying from sweet to salt water can vary between one year and eight years.

Once large enough, Atlantic salmon change into the grilse phase, when they become ready to breed and return to the same freshwater tributary from which they departed as smolts. It is believed that the salmon’s navigation for this journey involves a combination of magnetoception and the fish’s sense of smell as it nears its destination.

This return from salt to fresh water occurs from September to November, the time of the salmon run. After spawning most Atlantic salmon die and the salmon life cycle starts over again.

Many obstacles – some natural, some artificial – face salmon as they migrate upstream to their spawning grounds. One of these is formed by Shrewsbury Weir on the River Severn, the UK’s longest river.

This year jettybox.com was on hand to record the salmon run over the weir; and do so in slow motion, which adds a poignant beauty to this annual spectacle.

Author: Steve Woods

Generic carbon-based humanoid life form.