The Washington herald., 1908-06-14

Sediment, as well as the bottom mud, is
composed OF finely comminuted fragments
OF vegetable matter. seaweed. &c. max
ing perfect feeding grounds.
Bury Themselves Alive.
Large oysters are not as susceptible to
the effects Of mud, but even these full
grown oysters are easily smothered by
burial in the rapid deposit Of mud or sedi-
ment. Treshets and heavy seas often
cause great damage by the amount OF
mud, sand. and debris which they carry
upon the beds.
Gales rarely have an influence upon
adult oysters in deep water, but in shall
low water they often wreak con3idersble
damage on the beds. Heavy surf occa-
sionally carries away the oysters and
throws them upon the beach or buries
them In sand. Sometimes, before the oys-
ters are killed In this way. the erodng
effects of the currents again uncover the
beds. but In most cases they are pracu
cally destroyed. both old and young be-
ing smothered by the everything deposit.
In winter ice grounding upon the beds
In heavy weather does much damage The
oysters also become temporarily affected
by the mere freezing OF the water. and in
some localities become dark and slimy
and worthless for the market. and ten
days or more must elapse until they be-
come III for use again.
The fry are more affected by weather
than the adults and IL has been found
that in the swimming stage they We're
killed by thunderstorms. by cold rains.
and by sudden falls in temperature.
The mature oyster feeds upon both
vegetable and animal food the particles OF
al,
fry and younE spat consume relatively
large quantities OF bacteria and monads.
among the most minute organisms known
10 the microscopic. The parent oyster
Will also eat its own fry, and the quantity
OF young oysters lost In this way Is doubt
less enormous. 200 fry having been found
in the stomach OF a single individual.
How an Oyster Eats.
In feeding the oyster simply opens it's
shell and admits the influx OF water with
its contained organisms. The feeding
time Is always at high tide. and from ex-
periments made upon oysters caught In
the morning and others taken at night, Il
has been found from an examination OF
the stomachs that the bivalves feed only
by daylight The exact manner In which
the oyster cats is a simple one. The
water drawn into the mantle cavity by
the action Of the ella Is altered through
the rectangular openings IN the gills into
n chamber or tube lying above the gills.
whence II passes backward and out OF
the shell In a current dorsal 10 the enter
ing stream The particles OF food in the
inhOwing stream become entrapped I'm a
sticky mucus IN part. are carried IN a
steady stream toward the mouth. the mo-
ton being impaired TO the mass by the
rhythmic action OF the ella. The palp
and mouth are also ciliated. which insures
the continuance Of this current into the
stomach. where the food particles under
go digestion
Despite the thick, ormor-lke shell OF
the oyster. II is preyed upon by many
enemies. In the young state. as already
said, the spat is often destroyed by the
parent oyster and not only by It, but by
other molusca. lingulas. worms. sponges
and hydrolds. Probably also the men
haden, the alewife. and other FISH equip
ped with delicate sitting apparatus find the
oyster fry In their dietary. The condi-
tions Of life upon an oyster bed are favor
able TO the rapid growth OF sponges
barnacles. mussels. &C. which establish
themselves on the young growth and fire.
quently smother Il.
Oysters Go TO War, Too.
The adult oyster has enemies which in
jure Il by direct attack. In these waters
the drumfsh Is the most destructive 20
oyster beds. the oysters being consumed
by the fish as food. Whole beds OF oys-
ters are cleaned out by this fish.
which often comes in schools OF consider
able number some OF the skates and
rays Of the Eastern coast have similar
habits. The oysters in the Chesapeake
and adjoining regions suffer most fr,m
the effects Of drills. This is the tiny snail
Ike mollusks which. by means OF rasp-
ing tongue, drills hole into the shell Of
the oyster, through which It extracts the
soft parts In New York and New Jersey
waters the starfish is the most dreaded
enemy OF the oysterman. This fish trav-
els in schools. and sometimes before the
owner is aware Of what is going on his
beds have been cleaned out.
The number Of enemies Of the oyster in
various localities Is far too great 10 be
enumerated: but among the complex and
varied life which seeks the oyster beds
there are friends Of the oyster. and Of
these the crab Is one. The law Of the
oyster bed is give and take. and in this
ARRANGEMENT ol llle soCldl System lndt
obtains far under the surface. away from
the strange world above. the crab plays
the humble part Of scavenger. 1t is he
that moves from place 20 place gathering
up the refuse and the destructive dead
matter which might otherwise injure his
friend the oyster and in this manner
each inhabitant Of the oyster bed gives
and takes a large number Of the organ
isms. giving something for the general
welfare and taking something for its own
well being.