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An
Article by Simona Santini
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A
short introduction by the Author:
My name is Simona Santini, 31, and I am a
biologist, a fish keeper and a scuba diver. Every thing in my life,
as you may see, is related to fish; to study, watch and breed them.
I live in Pisa, Italy and am currently doing some research at the
University. My wildest dream is to scuba dive in Lake Tanganyika,
but this is almost impossible for the time being. The cichlids I am
keeping at the moment are: Cyphotilapia frontosa "Kasanga",
Julidochromis regani "Kipili", Tropheus sp. black "Ikola",
Tropheus sp. red "Chilanga", Eretmodus cyanostictus
"Zambia", Cyprichromis sp. Jumbo "Kitumba".
I wrote this comment on fish
hybrids just to explain that the evolution is probably the most
interesting subject related to fish and that people thinking of
"improving" species are, at least, presumptuous.... |
The title may seem odd:
“And now they’re trying to convince us that hybrids have a (real)
value? We’ve been pestered for months when trying to sell/trade a fish
at the annual auction (Is it a “pure breed” ? Are you sure it’s not
a crossbreed between the Tanzania variety and the one from Zambia?!?!)”.
Take it easy it’s all perfectly clear and that’s why I’ve put the
term hybrid among “quotes”; I need it to make my opinion more clear. Hybrids, in any tank, have to be avoided,
period! They have no value at all and any serious cichlid keeper should stay
away from them. And to clarify things further here comes the reasoning:
In the past (by the way, not
that far ago!) the concept of “species” had been defined relying on the
ability of specimens of opposite sexes to spawn giving birth to fertile
fry. They used to say: “if their offspring is infertile then the parents
should come from different species”. But what happens if they manage to
breed? I keep in my tank the result of what I thought to be a “normal”
spawning between a male and a female Black Altolamprologus calvus. Well
… spawning took place in a community tank hosting, among others, five
Neolamprologus caudopunctatus. The fry were looking like A. calvus, but
upon their growth they started to look like N.caudopunctatus, or better,
something in between: the shape was that of N. caudopunctatus, but the
mouth looked like A.calvus, the colours looked like A. calvus but the fins
like N.caudopunctatus. Till now I do not know how it happened since the
male A. calvus was fertile and really “active” during that spawning.
What probably happened was that a male N. caudopunctatus decided, while
the spawning was still taking place, to “spray” a bit of its own sperm
and unfortunately he was capable of wasting an otherwise perfect brood.
Then what would you answer to the question "do A. calvus and
N.
caudopunctatus belong to the same species"? If - as I DO hope - your
opinion is "NO", why the hell did they succeed in breeding?
The old definition of
“species” doesn’t fit any longer; chances are that the fry will be
infertile and - since I did not dispose of them - that’s my last hope.
If there’s a thing I do NOT need is fry from those fishes, period! But
the main question is still there: How is it possible for two species which
are so profoundly different to crossbreed?
The answer has to be related
to the fact that those two species of cichlid are, so to speak, “young”. Lake Tanganyika, the environment
where those two species came from, is also – from a geological point of view – young, being the
result of earth’s surface movements about 12 millions years ago.
Consider that the human species became significantly different from
“monkeys” about two million years ago. However, most mammals
started to follow different evolution paths between 65 and 10 millions
year ago. Then the lake is young and species populating it are even
younger. Two really "young" species even though they are
different, still they have only a few genetic differences. Genomes are,
still, quite similar in the cells of the two animals. This results in the
chance of interbreeding. The fact that two different species can’t
interbreed is because of a lot of tiny, slight, insignificant differences
hidden in the genomes of two species living “close” in the wild. There
is a point when those tiny, slight, insignificant differences begin to be
“too much” to allow milt of male “A species” being compatible with
eggs of female “B species”. At this point the two species will be
considered different by humans. In reality, the two species started to
“differentiate” from each other long before those tiny, slight,
insignificant differences started to add up.
Ichthyologists and genetists
tend to consider “different species” some species that only differ in
color. Just a few years ago there were only Tropheus duboisi and T.
moori,
while right now there are, at least, six different species. We are also
aware of the fact that in the Rift Valley Lakes there are still species
which are undergoing their process TO BECOME DIFFERENT. Being that young
they haven’t been still able to fix all their own “characteristics”; they simply haven’t had the
time they need to finish the process. Any kind of uncontrolled
crossbreeding regardless of whether it has been intentional or accidental
(mostly in a “small” environment such as a tank) is simply a step back
in the evolution path which for millions of years selects and defines
separate species. It needs centuries of tiny, slight, insignificant
differences to differentiate two species naturally. On the other hand, it
only takes an ignorant fish keeper to turn back the clock and God only
knows how much …
Crossbreeding and producing
hybrids is an unlucky event which every aquarium keeper involved in
spawning in his tanks had had the opportunity to look at, at least once in
his life. The main point is not to crossbreed on purpose just in order to
“produce” something new at all cost. Generally speaking, those fishes
are ugly (from an aesthetic point of view) and furthermore they are
"monuments" from a different time point in the course of evolution.
There’s no scientific interest in producing hybrids - this should be
clear to all of us. We all know that it is possible to get hybrids so
there is nothing new to discover by producing those unfortunate creatures.
There is no way to describe anything (neither phylogenetically nor
taxonomically) on these fishes. There’s no use in trying to crossbreed
cichlids in our own tanks to see if it works. This is Goofy’s science.
Evolution links among the different species are studied by means of an
in depth analysis of data, repeated measurements of their morphological
characteristics and study their genetic sequences.
However, things are far more
serious (worse I would say) if the aim of crossbreeding (mixing eggs and milt of
different species) is commercial. I would just refer to the Red Blood Parrot
(possibly the result of breeding Amphilophus labiatus and Heros severus).
As in this case, the
result will be the distribution of something that could never exist in the
wild.
This is the main point, and “crossbreeding addicts”
seem not to get it right. Hybrids appear in a tank since a tank, despite
all our efforts, is an unnatural environment for our fish which simply try to
do their best. No matter how huge the tank may be it will always be very
little compared to the space they would have in their natural environment.
Crossbreeding is the result of living in an overcrowded environment and
would never happen in the wild among the very same two species. Each one would
have many more opportunities to meet a specimen of the opposite sex but SAME
species instead of one of a DIFFERENT species. It’s a huge mistake to
believe that if Mother Nature (who is that after all ?) hasn’t set up
“genetic blocks ” to avoid crossbreeding then we’re allowed
to crossbreed them. Those bringing up these arguments should better spend their time in observing nature
and studying
genetics in depth while at the same time examine the ethologic parameters
of their actions rather than pursuing easy money and/or
business needs.
As a suggestion to avoid this
mistake as far as this is possible : closely related species are better kept
in separate tanks. If this is not possible never keep a single specimen mixed
in a group of members of a different species. Sooner or later the “single”
specimen will be
forced to spawn with a different species. Colour morphs and/or geographical
varieties have to be kept separated, too. Keeping them in the same tank could
result in crossbreeding. This in turn will result in further distributing species
which are to become totally different than they should. This attitude will
reduce the biodiversity of the species on this planet considerably - which
is already at great risk for many reasons.
Despite all your efforts
sometimes it may still happen. This has been the case for my “calvauds”, but once is
more than enough! I haven’t “advertised” those fishes and neither
“distributed” them and I DO hope every clever aquarium keeper will do
the same. The aim of this article is to convince everybody that hybrids are
“bad” culture, as further away from nature and REAL science as it can
be.
You
may contact the Author by
Email
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