17/06/2005 - Worried ecologists
face an anxious wait over this weekend to
find out whether one of the last Yorkshire
strongholds of the native white-clawed crayfish
has been invaded by it’s bigger American cousin,
the signal crayfish.
The Environment Agency’s ecology team, based
in Leeds, was alerted to the potential infiltration
by an angler who thought he caught a signal
crayfish while fishing in the River Aire near
Silsden.
Now the team will set a crayfish trap in
the river and see what they can catch. The
trap, much like a lobster pot, will contain
oily fish as bait. The crayfish should smell
the bait and crawl through the open end of
the tube until falling down into a pot, unable
to escape.
Biodiversity team leader for the Environment
Agency Martin Christmas said: "This could
be terrible news for the native crayfish population
in Yorkshire.
"Its American cousin often carries a
plague that can quickly wipe out the natives,
but is harmless to the Americans. They also
take over the available habitat and food sources
by using their size to bully the smaller native
white-clawed crayfish.
"We are keeping our fingers crossed
that it’s a case of mistaken identity, but
won’t know for sure until after the weekend."
Anglers often use crayfish for bait when
fishing for chub and this is a common way
for the American crayfish to be introduced
to rivers and streams. However, it is illegal
to introduce them to rivers or streams.
If American signal crayfish are confirmed
to be in the river this will put paid to the
conservationists’ ideas of increasing the
native population.
Plans were being made to increase the population
of native white-clawed crayfish by introducing
others from nearby streams to encourage them
to breed.
The team will find out by Monday what the
trap has caught and will know more then about
whether the Americans really are set to take
over the river.
The Environment Agency is the leading organisation
for protecting and improving the environment
in England and Wales. It is responsible for
making sure that air, land and water are looked
after by today’s society, so that tomorrow’s
generations inherit a cleaner, healthier world.
