The Key West citizen. [volume] (Key West, Fla.) 1879-current, 1953-01-15
SEA
SECRETS

ture to the tarpon's dorsal fin and
what is its use?
Bob Cartwright, Fl. Lauderdale,
Fla.
A. This structure is an elonga-
ton of the last supporting ray of
the dorsal fin (the fin on top of
the back, and resembles a short
whip or thong in shape. Its true
function has been a matter of
some scientific debate, but DR..
Chas. BREEDER of the American
Museum of Natural History states
that the elongate dorsal ray func-
tons in the tremendous leaps that
the tarpon (Megalopa atlanticus)
is famed for. According to him,
the ray (Which is concave below
adhereS to the side of the fish,
bending and securing the dorsal to
the right or the left, so determin-
ing the direction of fall. A similar
structure is found in the thread
herring (Opisthonema), but this is
thin and soft and probably has no
definite function.
Q. Are there really seven seas?
A. Modern oceanographerS re-
cognize only four great seas or
oceans. These are: The Atlantic,
Pacific, Indian, and Artic Oceans.
By dividing the Atlantic and Paci-
fic Oceans into North and South
Sections and including the Antarc-
tic (Which is actually part of the
Atlantic and Pacific), the idea of
seven seas may be construed.
Actually, the term "seven seas"
is very ancient one and ante
dates geographical knowledge of
our preSent-day oceans. The seven
seas are referred to in literature
of the ancient Hindus, Chinese,
PersianS, Romans, and other
nations. In each case the term re-
ferS to different bodies of water,
even including mythical seas.
@. Is it possible to keep bait
shrimp alive for a certain period
Of time, and if so, would they sur
vive in fresh water? Is it possible
to ship live shrimp by plane?
A. The commercial bait and food
shrimp (Penaeus sp.) of the Flori-
da coast are rather delicate in
captivity and special care must be
given them in order to keep them
alive. They will not live in fresh
water. In areas of clean salt water
they may be successfully kept in
pens of fine mesh hardware cloth
with sand in the bottom so that
they may bury themselves during
the day. Heating, overcrowding,
and allowing food or other debris
to remain in the pens, account for
high mortalities among shrimp. In
concrete or wooden shore tanks it
is necessary to provide clean, run
ming sea water or ample aeration,
otherwise Stagnation will occur.
Feeding every other day of cut
mullet, shrimp, oysters, or bar
nacles will usually maintain cap
tive shrimp. To prevent pollution
it is extremely important to re-
move any excess food from the
pen or tank after feeding. Live
shrimp could probably be shipped
successfully by plane in waterfilled
cans, but some mortality should be
and the operation would
be fairly expensive.
Q. Can fish swim backwards?
A. A number of fish, such as
cells, are capable of backward mo-
vement, although obviously this is
not their normal method of pro-
gression. Perhaps the best example
Of this is found in the Gymnotidae,
a Family of freshwater fishes of
the American tropics which are
allied to the electric eel (Which is
not true eel at ALL. The Gym
notidae are band-like or eel-shaped
fishes, but the body is held stright
in swimming and motion is Drc.
duced by a ripping movement Of
the long anal fin which extenoS
along the under surface of the fish.
BY changing the direction Of the
ripples, the fish may move back
ward or forward with equal faci-