SEA TROUT - TAILS
IN THE RIVERBANK
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| An amazing underwater tale of a tenacious fish |
Chris
Packham uncovers the hidden world of the New Forest streams with
the Environment Agency Fisheries team.
The New Forest
rivers are of international importance and home to an extraordinary number
of species from the primitive Brook Lamprey to the freshwater equivalent
of the shark - the fearsome Pike.
Each year
they also witness an amazing spectacle - the spawning of the Sea Trout.
Sea Trout
are in fact Brown Trout that have decided to take to the sea.
Incredible life-cycle
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| Dominic
Longley, 'within a 100metre stretch, we've seen 10 or 12 different
species' |
But every
year they return to the rivers to spawn at almost the same spot where
they were born.
These impressive fish can reach 31" (78cm) in length and weigh anything
up to 20lb (9kg) and yet they make their way through shallow water to
the tops of the forest streams.
The sea trout
only return for a few weeks each year and despite their size remain largely
unnoticed.
The female - or hen fish - creates a shallow depression in the river bottom
known as a redd, in which she lays her eggs. She does this by thrashing
her tail in the gravel.
Dominic Longley,
a fisheries officer with the Environment Agency, told Inside Out, "The
Sea Trout is a creature that has managed to go through this incredible
life cycle unseen.
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| A
classic male or cock Sea Trout from the Lymington River |
"You even speak to local people and a lot of them are completely
unaware of their existence.
"They're a low profile creature and it makes it even more amazing
that you see a small tributary of a river in the New Forest and see these
enormous ocean going fish spawning with barely enough water to cover their
backs and when you see that in the depths of winter in the middle of a
woodland it's quite astonishing."
The Environment
Agency is responsible for monitoring the wildlife in the forest streams.
The slippery Eel
Each year they survey the rivers by sending an electric current through
the water that stuns all the creatures close by.
They then
measure and weigh them and take scale samples from which they can learn
the life history of each fish.
The fish are then returned unharmed.
Inside Out
filmed the agency electrically stunning a 100 metre stretch of the Lymington
River which produced almost a dozen different species including Eels which
have the most amazing life cycle.
They are thought to spawn in the remote Sargasso Sea in the middle of
the South West Atlantic.
The animals then drift back in ocean currents before entering freshwater
rivers where they remain for anything up to 50 years before returning
to the sea.
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