sea trout from the River Tweed are migrating as far as Denmark, Germany and the Netherlands, new research has confirmed.
The recapture of a tagged sea trout by a Dutch angler off the island of Vlieland in the Netherlands backs up previous research into the migratory habits of the fish.
Dr Ronald Campbell of The Tweed Foundation believes this latest development, part of a new study into the migratory habits of sea trout in the North Sea, poses as many questions as it does answers following 90 years of research.
In the 1920s, 1930s, 1950s and, most recently, in 2007, tagged sea trout from the Tweed were recaptured off the Dutch, German and Danish coasts. The 1920s and 1930s fish were tagged as kelts; the 1950s fish as smolts.
The record, however, was a fresh fish tagged at Paxton House netting station in September 2007 on its way up the Tweed that was later caught in May 2008 off the island of Sylt, near the Danish/German border.
Dr Campbell said: “These records of a long, southward, migration of sea trout from this area have now been joined by the recapture of a sea trout tagged on the Northumberland Tyne as part of the Second Tyne Tunnel Monitoring Programme in November 2010 and recently caught by a Dutch angler off the island of Vlieland. This is the second of the West Frisian islands, the next along to the east is Terschelling and the fourth along is Ameland, where a Tweed tagged sea trout was recaptured in 1928.
“Another, 1929, Tweed recapture was simply listed as ‘Frisian Islands’ so was made in the same area. Obviously the Frisian Islands are a place that both Tweed and Tyne sea trout go to – but who do they meet there? Are there sea trout from Danish and German rivers there as well?”
Morton Heddell-Cowie of the Environment Agency’s Second Tyne Tunnel Monitoring Programme explained the Tyne recapture.
He said: “The recaptured sea trout was a female 2.1+ fish (that is, she had spent two winters in the River Tyne and one at sea) and had been originally caught and tagged during one of the Tyne’s broodstock collection netting sessions on the North Tyne at Ridley Stokoe, five miles upstream of Bellingham, on November 3 2010. She was recaptured by a Dutch angler, Mr Folkert Janssen, in May.”
The Living North Sea study, of which both The Tweed Foundation and the North-East Area office of the Environment Agency are partners, aims to establish the sea-trout migrations around the North Sea.
One aspect of this work is the definition of the genetic identities of sea trout from rivers around the North Sea so that any fish caught out at sea can have its home river identified. The recapture of tagged fish can be hit and miss, so being able to genetically find the home river of fish caught at sea can help work out migration routes.
The Living North Sea study, also supported by the Dutch Royal National Anglers Association, is an amalgamation of bodies interested in sea trout in the North Sea and aims to improve knowledge of what our fish do once they pass Spittal Beach in the Tweed estuary.