Observations
of Social communication - Chester Zoo 2005
Weakly electric fish continually probe their environment electrically.
They use electro location, a specialised sensory guidance system
for environmental navigation. Electro-location works by 'electric
organ discharge' (EOD) the fish generates a current field
which emanates from the base of its tail and then converges on the
tip of its tail. It continually tests the conductivity of the water
around itself, detecting distortions in its own electric field. ,Electro-receptors,
on the body surface monitor distortions in the current field.
- In the case of the strange looking Long-nose Elephant Fish
Gnathonemus petersii (Mormryd
family), these occur as a series of clicks and pulses, varying in
rate and amplitude. Each click is specific to species.
Hear this recording from a single
fish in my own tank mp3 252kb, Stereo electrode recording.
(Above) Chester
Zoo. A
large community tank
of Long Nose elephant
fish,
Group sound mp3 231kb] Stereo electrode
recording
Swimming In group mov 1.5mb +
Stereo electrode recording
I was lucky enough to get behind the scenes at Chester
Zoo to make some recordings. They
have the best
collection of Mormryds in the UK - 6 different species interacting
each 'speaking' a different language. And yet in this continual conflict
they seem to thrive. Watching
a tank full of these fish is remarkable; the behaviour is highly
territorial, they continually squabble over spaces in the tank.
Stereo electrode recording from Chester Zoo 2005,
Large Community Long Nose elephant fish,Group
sound mp3 231kb]
(Above) A
Down poker
at Chester
Zoo.
Some sources say that strong discharges are emitted occasionally
to stun prey. Although in the weak electric fish like this it is
not proven. It is generally accepted that signals are used for and
social communication in their 'low visibility environment'. some
species - the Long-nose for example; are able to turn off the electro-sence,
possibly to hide from other larger fish of its won kind. It has recently
ben discovered that they are able to make acoustic sounds in this
inactive electrical state, these have been linked with courtship
rituals.
Bolton
Art Museum & Aquarium.
Pete
Liptrot
introduced
me
to
the
fish
they
call
the
Blue
head
(Sternopygus
macrurus)-
even
though
it
is
green. According
to
theamazonian-fish.co.uk -There
are
currently
23
sternopygid
species
which
are
grouped
on
the
basis
of
dentition,
skeletal
structure
and
sensory
pores.
Genera
include
Distocyclus,
Eigenmannia,
Rhabdolichops,
and
Sternopygus.
These
are
essentially
nocturnal
animals.
This
fish
at
bolton
is
huge,
it
was
so
big
i
could
only
get
good
film
of
small
details
through
the
tank
because
of
reflections
on
the
glass.Its
very
presence
is
hypnotic
and
somehow
mesmerising
mysterious
-I
think
this
is
because
it
has
almost
no
eyes
and
a
menacing
gait.
Recording from this fish was really difficult - the low frequency
was difficult to hear with normal head phones. I had to turn the
levels to max the try and detect the signal - there was a lot of
noise - Pete was kind enough to turn off all the lights, heaters
and pumps to minimise electrical interference.
Above
- The Blue head Sternopygus
macrurus at Bolton
Art Museum & Aquarium.
Neurosciences
Intégratives
et
Computationnelles.
In
Paris
I
contiued
the
research
for
the
project
through
a
residency
at
ENSAD. Most
of
my
time
was
spent
learning
MAX
MSP
-
but
I
found
that
just
outside
Paris
was
a
research
centre
where
they
kept
a
selection
of
electric
fish
for
research
purposes.
They
were
extremely
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