{"id":6565,"date":"2015-10-26T13:20:49","date_gmt":"2015-10-26T13:20:49","guid":{"rendered":"http:\/\/xislblogs.xtreamlab.net\/slwoods\/?p=6565"},"modified":"2015-10-26T13:43:08","modified_gmt":"2015-10-26T13:43:08","slug":"leaping-salmon","status":"publish","type":"post","link":"https:\/\/www.slwoods.co.uk\/?p=6565","title":{"rendered":"Leaping salmon"},"content":{"rendered":"

Wikipedia informs us<\/a> that the Atlantic salmon (Salmo salar<\/em>) is found in the northern Atlantic Ocean and in rivers that flow into the north Atlantic.<\/p>\n

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.<\/p>\n

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

When the parr<\/em> develop into smolt<\/em><\/a>, 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.<\/p>\n

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

This return from salt to fresh water occurs from September to November, the time of the salmon run<\/em><\/a>. After spawning most Atlantic salmon die and the salmon life cycle starts over again.<\/p>\n

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.<\/p>\n

This year jettybox.com<\/a> 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.<\/p>\n