The Salmon Run.

                                                                   
                                                                                    Salmon.

I spent a couple of hours on Saturday morning earlier this month at a weir on the river Dove hoping that the recent rains would have raised the river level enough to spur the Salmon waiting in the deep pool beneath the weir into action. Although one or two fish were seen trying to get over the weir, there is not enough water for them at the moment. It is around this time of the year that the Salmon run on the river begins in earnest but without a heavy rain fall, the fish can not get over the many obstacles that this river system has in place.

Salmon Leaping.

The Salmon have been making there way up the river system for several weeks now and they will be waiting for heavy rain falls to raise the river level to enable them to complete their journey from the North Sea to the upper reaches of the river Dove to the spawning grounds or the Redd's as they are referred to, an area of fine gravel beds where they can spawn. The Salmon having travelled through the North Sea to the Humber estuary near Goole, will make their way up the river as far as they can travel and then they will lay their eggs in a depression made in the gravel on the river bed with their tales. The hen fish will lay her eggs into the depression first and then cock fish will then try to cover the eggs with his Milt ( sperm ) in an attempt to fertilise as many eggs as he can. They will then cover the eggs over with more gravel, where they will remain until they hatch around 5 to 7 months later. When the eggs hatch they are known as Alvin's. As they grow and develop, the markings on their sides become more prominent and they are then referred to as Parr. During this growth stage many of the thousands of eggs laid will have already been lost to predation by birds, other fish and larvae of dragon flies and other predators. The young salmon will remain in the river system until the time comes for them to make there way out to the open sea, on there way they will be met with many more obstacles that will reduce even more the number of young salmon on this long and treacherous journey. Over the next year or two they will live in the sea and put on weight and grow into adult Salmon when they will then start their perilous journey to return to their birthplace to start this cycle of life all over again. Once the cycle has been completed the Salmon normally die as a result of having lost nearly all their body weight during their spawning activities and the fact they do not feed once they return to fresh water from the sea. It is believed that of every 8,000. eggs laid only 2 fish will survive to return back to continue the breeding cycle.

The above chart refers to the Atlantic Salmon but the life cycle of the fish in our rivers and the North Sea are the same.

The recent rain over the past few days has seen an increase in movement on the weir since my last visit. Rain entering the river system from the hills in the Peak District has swollen the river water and pumped in plenty of oxygen giving the fish a chance to get over the weirs and get through the fish passes like the one at Tutbury, boosting their chances of reaching the spawning areas further up stream.