NEWS
Lamprey Lookout!
Have you seen a strange fish that looks like a
fat and blotchy eel, with a circular mouth and
a bunch of small holes behind its eyes? If so,
you have been lucky enough to spot a sea lamprey,
a parasitic fish which experts think is returning
to the Thames. And for those of you interested
in historic cuisine - lampreys were Henry I's
favourite food (it is even said he died of a surfeit
of lampreys!).
Lampreys Return to the River Thames
The sea lampreys are back!
A bit about…
The sea lamprey, Petromyzon marinus is
a parasitic fish which attaches itself to the
skin of large fish at sea and then feeds on the
blood, body fluids and musculature. The species
travels into freshwater rivers to spawn by laying
eggs in shallow nests of gravel and stony areas
in the current. Most die after spawning. Lampreys
are primitive fish, instead of a proper jaw they
have a circular mouth with rasp like teeth that
acts as a suction cup and allows them to attach
to larger animals. Lampreys themselves can grow
to about the size of a man's arm and weigh over
5 lbs.
Good news!
The sea lamprey was once extremely common in the
Thames and throughout Europe and was an important
food fish (hence Henry I's tastes). However, pollution
and water control development has seen the demise
of most river spawning runs in Europe and the
Atlantic coast of the USA. Today, the lamprey
is considered a rare species and it threatened
in Western Europe, where it is listed in the Habitats
Directive, the Bern Convention and is a UK Biodiversity
Action Plan species.
However, in the past two years, dead lampreys
have been discovered on the Thames foreshore in
the Hammersmith, Barnes and Kew areas. As eggs
were found near the animals and a few were still
carrying eggs, this would be the first reported
spawning of this animal in the Thames in modern
times. Experts assume that the real spawning population
is much larger and there is cause to believe the
lampreys have returned. Since they are also very
sensitive to water quality, the presence of lampreys
is a good sign for the health of the river and
may impact on the future management of the estuary.
The Environment Agency is keen to find out more
about these fantastic animals and the future of
the Thames as a spawning grounds. Anyone who is
out working or walking along the foreshore is
asked to keep a lamprey lookout! If you do find
anything, please contact Thames
Explorer.
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