Wausau pilot. [volume] (Wausau, Wis.) 1896-1940, 1915-10-05


expedition, very little was known
garding the fish life of the abyssal
CNC n depths of the Only about 80
~ species were known. But the won
NA1 derful collections brought back by the
w. 4 Challenger" from her four-year
| cruise QS73-1S76) made known the
| " vast diversity, the strangeness and
I even weirdness of this fish fauna.
Several hundred kinds of deep-sea fishes had
been collected-some of them dredged from
depth of more than a mile-and it required
huge uuarto to describe and picture them. From
this volume dates real knowledge of the
fishes of the abyssal deep. The Challenger
expedition was, inded Columbus voyage" in
Ichthyology; it opened new chapter in the his
tory of the science
Since that time many deep-sea exploring ex-
petitions have been sent out by the various ma
tions and hosts of other fishes have been
brought up from the oceans in all parts OF the
world More than thousand species are now
known, and we can appreciate at its full value
the richness and strangeness of this fauna.
Moreover not only do we know the fishes them
selves but as a result of the scientific investi-
cations carried on by the various expeditions,
we now know a good deal of the physical con-
ditions under which they live, so that we can, in
a measure at least explain the why and where
fore of their extraordinary characteristics.
When we think of life in the dee2-sea, there
comes to mind first of all, the enormous pres
sure which these creatures must withstand.
This pressure becomes the greater the deeper we
go down, and in the profoundest depths it equals
thousands of pounds to the square inch The
result of this pressure is that the tissues OF these
fishes are tender and loosely knitted together.
When they are brought up out of the dark
DEPTHS, and the great pressure under which they
live is removed, the explosion of the gases with
in them bulges out the eyes, and often blows out
the viscera through the mouth. while the mus
cIes collapse, leaving them soft and 1abby like
moist rags Most deepsea fishes are very small
also, usually only a few inches in length, and 1t
is probable that this reduction in size has come
about, to some extent at least, from the great
pressure under which they live.
Another important condition is the dimness of
light or even darkness in the profound depths
of the sea- If we imagine ourselves descend
ing into the deep ocean, we see the light grow
DINNER and DINNER as we go down, until finally
a level is reached beyond which no light pene-
trates at all The entire vast depth below it. is
in eternal darkness. Now the fishes living in
this dim light, in total darkness. have been
profoundly modified by it, In some forms the
eyes have become very small. and in some cases
have entirely disappeared. There are even fishes
in which the skin and scales of the body have
grown over the place where the eyes should
be. so that these fishes are, as has been aptly
said blind beyond redemption" Other forms.
on the other hand. have been affected in an
entirely different way The eyes, instead of
growing smaller, have grown larger. as if in an
attempt to catch every feeting ray of light. In
some fishes this has been carried so far that the
eyes have become like enormous goggles
Most deep-sea fishes have luminous organs Of
one kind or another. so that they carry their
own light about with them. In some the entire
body glimmers the coating of slime which
exudes from the pores and lateral canals, emit
ting a soft silver glow. In others rows of mi
mute luminous organs run along the sides of the
body. or there are flashing Hght-spots on the
head or face. What a wonderful sight would be
to US a small black fish fitting through the ST.
lence and darkness of the deep with its head
lights and row of pores cleaning through the
darkness like some small ship passing through
the night with its portfolios all aglow! Some
deep-sea fishes have a luminous organ at the
end of a feeler the head.
A pertinent question may be asked: How do
we know these fishes glow and glimmer since
no human eve has ever beheld them in their
abvssal home? We know this partly from anal
ogv and partly from actual observation. When
one is in a boat in the tropics on one of those
sultry nights when everything is a dead calm.
and the black clouds hang low that sky and
sea form one continuous baekness, then one
may see the glimmerng fishes darling out of the
path of the boat their forms. silvery and ghost
like outlined for one moment against the black
ness of the sea This effect is chiefly due to
the oxidizing of the Shiny secretion covering
their bodies. Why shall not believe. then
that in deep-sea fishes a similar phenomenon
takes place. particularly in many of them
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