Evening star. [volume] (Washington, D.C.) 1854-1972, 1904-08-06

shore their own larvae or fry, as wen as
that of many other mollusks, or DryoHoa
and minute embroys of polyps and worms.
together with other fragments OF animal OF
vegetable origin. and sometimes even min
ute crustaceans. In variety of food the
oyster, therefore. has a wide range or
choice 1t therefore follows that when we
eat an oyster we are consuming what Il
required millions of the minuteSt organisms
in the world to nourish.
THE oyster is consequently sort OF
living store house for the incorporation
and appropriation of the minute life OF
the sea. which could never be rendered
tributary to the food supply of mankind
in any other way. except through the &C
ton, growth and organization OF this
mOlluSk."
Very Much Of q Cannibal.
The adult oyster Is very much of a
cannibal. for the report states that the
quantity of young oysters consumed by
the adult us doubtless enormous. 200 fry
having been found in the stomach of sin
gle individuals. Not only the free SWIM
ing fry. but eggs and spermatozoa are
led upon. and an insight Is here gained
into the ultimate fate of some of the
vast genital elements which the parents
shed into the water
However. in most regions which have been
investigated the plants constitute by far
the most important item Of diet. usually
over 80 per cent Of the food contents of the
ter The oyster is said to feed mainly dur
ing food tide. opening its shell at that time
to admit the influx of water with its con-
tained organisms.
An interesting portion of Mr. Moore's re-
port Is devoted to the enemies of the oys-
ter He says at all stages of its career the
oyster is preyed upon by more or less dan
gerous foes 1T might be supposed he
adds, that an animal inclosed in pom
derous armOr. which in times of danger is
complete encas2ment. would he free from
the attacks of enemies. but no organism has
ever evolved a protective device VIII CHI
some other organism has not found par.
TALLY vulnerable; and 1t must be remem-
bered that the oyster Is not always as well
protected we find it in the adult and
marketable cord ton.
I'm the young state. before attachment.
the minute and delicate fry is fed upon ex-l
tensively by the adult oyster and by other
mollusca. lingulas. worms. sponges and
hydrodS. Probably the menhaden the
alewife and other fish equipped with deli
cate sitting devices at times find the oyster
fry of some Importance in their dietary.
After the attachment of the spot other
enemies. active and passive, wage war upon
it. The passive enemies affect it's welfare
by consuming its food or by smother1ng II
beneath their own more active growth VI
the former class. mussels, lngulas, etc.
examples, but as the food upon an
oyster bed is usually sufficient for all, this
IS not very important consideration. par
ticularly in the end an equilibrium Is
established through the intimate reapro-
city which exists between the various forms
of life.
The conditions of life upon an oyster bed
are favorable to the rapid growth of dense
sponges, mussels, barnacles. hydroids and
tube building worms. which establish them
selves upon the young growth, often IN
crease more rapidly than their hosts. and
in many cases overgrOW them TO Such an
extent as to cut off the supply of food and
oxygen. Aquatic vegetation sometimes has
the same effect when its growth becomes
extensive.
Enemies of Adult Oysters.
The active enemies of the adult oyster
are those which injure it by direct at
tacks. such enemies being found in most
of the classes of geological life having
aquatic representatives. Fishes of sew
eral kinds are found habitually on the
oyster beds. Most of these offer no di-
rect injury and they may even benefit the
oyster by keeping down the crowding
masses of hydroids and vegetable life.
but few species, of which the drum fish
is the most destructive on the Atlantic
coast. consume considerable quantities of
oysters as FOOD. AT times much damage
has thus been wrought to the beds in
the vicinity of New York and along the
New Jersey coast.
In San Francisco bay the stingray is
the most feared enemy of the oyster and
schools of them frequently clean out the
beds to which they gain access their
teeth being such that the shells are
crushed into fragments in their grasp.
Some of the skates and rays on the
eastern coast no doubt have similar hab-
it's. but they do not appear in sufficient
numbers to cause much harm The drills
are the most destructive enemies of the
oyster in the Chesa peake and adjoining
regions, as well as upon most of the
more important inshore beds northward
Inc most destructive of these is the form
known to naturalists as urosalpinx Gin
erea. 1t is Snail-like molluSk, which.
by means of its rasping tongue. drills a
tiny hole in the shell of the oyster
through which it extracts the soft parts
III Is only the younger oysters which are
thus attacked, as after they become about
Two inches long the shell is stout enough
to resist this foe. The loss sustained
from TINS source Is very great. as the
drills are often present in large num-
bers and continue their work through
out the year.
Upon brackish water beds the starfish l.
rot usually troublesome, and In Ch4sapeake
pay ~ pracicaily unknown, but in Long Is
iand sound. and especially upon the offshore
beds in the more saline waters If is Tho
most destructive enemy with which OYSTER
men have to contend. 1t is there extremely
abundant at times but it is a mieratory
form. and sometimes certain beds are I'M
moiested, while others nearby are almost
ruined by its threads The appearance
Oh this pest upon the beds is with
Is almost devastated before the owner is
aware of It's presence. Vast Swarms ar
schools sweep across the beds deyouriny
the oysters In their path. The migratio is
said to take place in the form of a win
row., moving in some cases at the rate of
about 800 feet per day
The starfish begins its destructive work
soon after it abandons it's free-swimming
larval condition, at time wh.n 1t is hard
ly larger than pins head. and continues
it through life. At first 1t feeds upon the
tiny spat but as it grows it increases the
size of its prey. though even the full grown
stars rarely feed upon oysters over two or
at most. three years old. Small oysters are
often taken bodily into the stomach of the
startish. 1t is not definitely known how the
oysters are opened but DR.. Paulus Schie-
menZ has pretty cOnclusyey demonstrated
the probability that they are actually pulled
open by muscular effort on the part of the
starfish.
Another annoying and frequently very de-
Structive enemy of the oyster is the boring
other enemies in that 1t consumes the shell
and not the soft parts of the unfortunate
oyster.
Crabs on the Atlantic coast are not re-
garded very destructive. On the con-
trary they serve as Scavengers, removing
dead matter from the beds, when it might
otherwise become foul and fatal to the
oysters.