Fish become very pale if they live in darkness. The ones in mines are not blind, and they would become coloured within a few weeks, or even days, if returned to the light. They have not evolved to be "white", they are genetically identical to normal fish. Much the same thing happens to people, but coloured fish like trout have other mechanisms to achieve a more marked change, more quickly.
There are blind, white fish in caves which have evolved to be that way, but not in Britain and not in mines unless they have come from connected caves. It takes a much longer time to evolve genetically, without deliberate selective breeding.
Fish can populate new waters by a variety of means, including birds' feet.
Eels are fish, but can travel over land very well, and often do so.
Mike
Dr M Worsfold,
Principal Scientist,
Charles Salt Research Centre
-----Original Message-----
From: mining-history [mailto:[log in to unmask]]On Behalf Of
David Hardwick
Sent: 25 July 2005 10:57
To: [log in to unmask]
Subject: Re: Fish in old mines
The subject of cave(mine) biology is in itself extensive. Many creatures
exist which are "blind" and/or "white" and the species is only found
underground.
Fish that fit into this category are not uncommon (I have seen them myself
in caves in England Ireland and Wales). I haven't yet seen any satisfactory
answer to how they got there - one would assume they evolve from surface
creatures but finding the same species in unconnected caves implies the same
process is happening in independent locations. Perhaps we would learn a lot
more about how evolution really works (or not) from scientific study.
Interesting stuff but I fear this is getting a little off the "mining
history" theme of this discussion group other than to say if you have a
level with a known last working date the presence of creatures which are
"white &/or blind" suggests a rapid evolution rate and the history of the
mine would then be relevant to the biologist.
Regards
David
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