GULh BIOLOOiq (.STATION
cAMtRON, LA. Private Libi
of
BULLETIN NO. 8.
THE' CULTIVATION OF OYSTERS IN LOUISIANA
BY L. R. GARY ('-(4 '^'ToV* JM
ISSUED UY THE
Louisiana State Board of Agriculture
and Immigration
CHAS SCHULER, Commissioner
BATON ROUGE:
•nB Daily Stath, OFririAi, Joornal o» Lodisiani,
1907.
GULF BIOLOGIC STATION
CAMERON, LA.
BOARD OF CONTROL:
N. C. Blanchard, President, Governor of Louisiana.
E. C. Caldwell, Vice-President, President of the State Normal.
J. B. AswELL, State Superintendent of Education.
Chas. Schuleb, Commissioner of Agriculture and Immigration
T, D. Boyd, President of the Louisiana State University.
('. E. Byrd, President of the Louisiana State Industrial Insti-
tute.
E. L. Stephens, President of the Southwestern Industrial In-
stitute.
STATION STAFF:
B. H. Guilbeau, B. S., Director.
L. R. Cary, M. S., Zoologist, in charge of Field Oyster Investi-
gation.
M. H. Spaulding, M. S., Zoologist, in charge of Experimental
Work.
R. S. Cocks, M. A., Systematic Botanist.
Frank Roberts, Treasurer.
E. S. Miller, Stenographer.
M. W. McCall, Caretaker of the Station Laboratory.
COXTI^XTS.
I'aijc.
Jitroducticn 5
Anatomy 5
Iieproduction and Develupnjfiit IQ
Physical and Biological Conditions on Oyster Beds 16
Food of the Oyster 24
Enemies of the Oyster 27
Destruction of Oyster Beds by Freshets and Their Recovery 32
Destruction of the Natural Reefs 35
Increase of Oysters by Artificial INFeans 37
Planting With Seed 42
Planting With Clutch 46
Fattening, Plumping 56
lilt: (I I.I iv.\i i()\ OF ()Ysri-:i!s is ij>i isi.wa
HY l>. K. C'AKV.
The following report is designed to set forth briefly th<^
l)rinL'ii)al facts relating to the subject of oyster culture in tlit-
I nited States, and to consider more in detail the problems that
must be met by those engaging in the oyster industry in thr
■waters of the State of Louisiana. It is intended primarily ;is
a guide for those who are interested in tlie t)yster industry- and
who have luid mt praclica! cxiici'lciicc in the nn Ihods in genei'al
use. 'I'o aid such persons to a more thorough undei-standin^
of the problems involved, the special chapters on the Anatomy
and Developm( nt have been introduced.
In a few instances attention has been called to some of the
more •'intensive" methods which are in use in other oyster-pro-
ilucing regions; but whivli on account of the expense involved
are not to be reconunendcd inr use in tliis'section.
AX ATOMY OF THE OYSTER.
The general structure of an oyster may be roughly repre-
sented by comparing it to a check hook'. Tlie covers of the book
will represent the two shells of the oyst»n-. oi)en on three sides,
while the back of the book represents the hinge, or the area
where the two valves of the shell are fastened together l)y the
hinge ligament (Plate I, Fig. 1. b).
The hinge ligament is an elastic structure ijiaced in such a
relation to the shells that it tends to throw their free ends apart.
To understand its manner of working, place a small piece of
rubber between the leaves of a book, near the back. Now. if
the free ends of the covers are closed, the rubber will be com-
j)ressed and will throw the covers apart as soon as the pressure
is removed. The hinge ligament tends, by its elasticity, to keep
the shell open at all times, and when the oysters are lyincr un-
disturbed on the bottom, or when tbe musele has been destroyed,
the ends of the shells are separated a little.
FIG 1 Ovster with right shell and mantle removed a and «■ origin of
^,nJlirof The nervous system: g. Kills; gc, cavity between the two mantle folds;
f h^nge J Hgamen" ; If! adductol- muscle ; m, mouth ; mt mantle tt.e arrows
show the direction of currents produced by the cilia: p', outer end of right pedal
musdeTsfexternal opening of sexual and renal organs of right side;.;, anus; »c,
ventrjcle of heart. ^ __, „,.„„„, „f fh« «v=t-pr a, duct of sexual
Fig. 2. Diagram to show sexual
gland. Other letters as above.
ms of the oyster.
The valves of the shell are not symmetrical ; the left oim, by
which the oyster is always attached to its support, is deep and
spoon shaped, while the right one is nearly flat.
'llie work of compressing the ligament and closing the shells
is done by a large, powerful muscle (Plate 1, Fig. 1, m), which
runs across the body between the shells, and is fastened to their
inner surface over the dark-colored spots that are always found
on the inside of empty oyster shells. This muscle, and some-
times the muscle scar on the shell, is called the "eye" by the
Louisiana oyster fishermen.
The shell is lined by a thin membrane, the mantle (Plate 1,
Fig. 1, mt), which folds down on each side, and may be com-
pared to the leaf next the cover on each side of the book. The
next two leaves of each side represent the gills (Plate I, Fig. 1,
g), the so-called "beard" of the oyster, which hang down like
leaves into the space inside the two lobes of the mantle. The
remainder of the book may be compared to the body of visceral
mass of the oyster.
In order to examine the soft parts of an oyster, the right
(.flat) valve should be carefully removed by cutting the adductor
muscle and breaking the ligament, thus exposing the right side
of the body. The surface of the body is covered by a fold of
tissue, the mantle (mt), which is attached to the body over the
greater part of its surface, but hangs free around nearly the
whole circumference. By tearing away the mantle, the gills will
be exposed. These are four folds of tissue, which occupy the
lower half of the mantle cavity and extend nearly the whole
length of the body. The space above the posterior (outer) ends
of the gills is occupied by the adductor muscle, or "eye." Be-
tween this muscle and the hinge, the space above the gills is
occupied by the body mass, made up of licrht-pnlnrod reproduc-
tive organs and dark-colored digestive orirans bound totrether
in one continuous mass.
Between the muscle and the visceral mass will be seen a
transparent, crescent-shaped space, the pericnrdmm, and, if the
delicate membrane which forms its walls be carefully cut away,
the heart (Plate I, Pier. i. ve and au). may be found without any
•diflficulty lying in this cavity and pulsating slowly.
In front of the gills (that is between them and the hinged.
8
there are four tleshy flaps — the palps (P), two ou each side oi
the body. They are much like the gills in appearance aud are
connected with each other by two ridges which run across the
middle of the body, and between these folds is the large, oval
mouth, m, which is thus seen to be sUicated, not at the open end^
of the shells, but as far away from it as possible.
As the 0}ster is inmiovably fixed to some support, aud has
no arms or other structures for seizing food and carrying it to
the mouth, the question how it obtains its food at once sug-
gests itself. To answer this question, as well as to understand
tiie relationship of the various parts of the oyster, a thorough
understanding of the structure and function of the gills is
necessary.
The gills are not only, as their name implies, breathing
organs for the aeration of the blood, but are also the means
by which food is gathered up from the water, carried forward
t(j the mouth, and by which currents of water are maintained
in the mantle cavity.
There are four gills in the oyster, two on each side of the
body. They are long, flat, thin, leaflike organs placed side by
side, and nearly filling the mantle chamber in which they hang.
Each gill is made up of two leaves, so that there are in all eight
gill leaves.
A single gill may be roughly represented by a sheet of
paper folded lengthwise, with the ends glued together, and the
opening of the pocket thus formed held uppermost.
The 'closed portions of the gills hang down into the mantle
chamber, side by side, while their upper edges are fastened to
each other and to the inside of the mantle, so that they form a
folded partition, like two W's, which divides the mantle cavity
into two parts : a lower chamber, in which the gills hang, known
as the gill chamber, and an upper chamber, into which the
pockets open, called the cloaeal chamber.
The cavity within each gill is divided by a series of vertical
partitions into small 'chambers, the water tubes, each of which
ends blindly below and opens above into the cloaeal chamber.
The walls of the water tubes are made up of a number of min-
ute rods, the gill filaments, placed side by side, each ridge being
separated from the next by a deep furrow. In the bottom of
9
eacli i'lirruw there are minute openings, the water pores, which
open into the water tubes, thus forming a communication be-
twt i.'U the two divisions of the mantle chamber.
Each rod, or filament, contains a minute blood vessel which
runs its entire length, and in these vessels tlie blood is purified
by the water which liils the gills and the chamber in which
they hang.
If a filament of one of the gills is examined with a micro-
siope, it will be found to be covered with minute hairs, or cilia,
arranged in rows (Place III, Fig. 3, c). Each of these cilia is
constantly swinging back and forth with a motion mueli like that
of an oar in rowing; but as the cilia are fastened to the gill,
which is immovable, they do not move forward through the
water, but produce a current in the opposite direction. The
united action of the cilia on the gills produces quite a vigorous
stream of water, which is drawn in through the open ends of
the shell, then forced through the water pores into the water
tubes, and from these passed to the cloaeal chamber and so
out of the shell again.
The food of the oyster consists almost entirely of micro-
scopic plants, which are more or less motile. These are drawn
into the gill chamber with the water; but as the water is forced
through th«' pores into the water tubes, the food organisms are
caught on the surface of the gills by an adh?sive slime that
covers the entire surface of the gills. The cilia striking against
the entangled food organisms push and roll them along toward
the mouth until they reach the end of the gills where they fall
between the palps. The palps are also -ciliated and carry tha
food forward until it falls into the mouth, which is always
open, and is ciliated so that the food is forced through thv3
oesophagus into the stomach. This process is going on when-
ever the shells are open, and the oyster is breathing, so that the
supply of food is practically continuous so long as the oyster
i' undisturbed.
Tn order to trnco the eourso of the di<_'osliv«' cnvify. ih.^
body of an oyster jnay be si)lit wilh a sharp Unif'r (.r razor.
Tf the cut is in the middle of the body, eaeli linlf will sliow
sections of the short oesophacrus. runnino- ;ip fi-opi the mouth.
and the irr<"'iil;ir stomach v.-fth thick Avails, surrounded bv the
10
dark green digestive glaud. Back of the stomach the smaii,
convoluted intestine may be seen, cut at several points by the
section,
REPRODUCTION AND DEVELOPMENT.
In the common, or Eastern, oyster the sexes are separate,
each individual being either male or female, but not both, as
iy the case with the European oyster, and in one of the species
found on the Pacific Coast. It has been maintained by some
observers, but the point is not yet definitely proven, that the
same individual may vary in sex from year to year, producing
eggs at one breeding season and sperm at the next.
While the sexes vary much in physiology, and in their
histological structure, it is impossible to distinguish between
the males and females by any known external characters. It is
only by a careful examination of the reproductive glands, or bet-
ter of the sexual products, that one sex may be distinguished
from the other.
The simplest method for determining the sex of an oyster
IS to examine a drop of the genital products, which may be
obtained by cutting into the reproductive organs on either side
of the body mass. If the drop is put on a piece of clear glass
and examined without any magnification, it will be seen that,
if taken from a female, the reproductive elements will have a
slightly granular appearance. In those taken from a male no
separate particles can be made out; but the Avhole mass will
have a slightly quivering appearance due to the cnmbinod move-
n (-.1^; of the spermatozoa.
RIPENING OF THE GENERATIVE ORGANS.
In the sin'ino-. when the water begins to become warm, cer-
tain -.'hanges manifest themselves in the generative oroans of
the oysters preparatory to the act of spawning. In the female
some of the minute eggs in the ovary increase in size and become
loosened from the follicles, or little pockets of tissue, in which
they have undergone their early development. All of the egga
which are to be discharged at one season do not ripen at the same
time so that the spaivning of each individual extends over a
greater or less period of time. An examination of the ovary
11
at any time will show ^reat numbers of immature eggs, most
of these being ova which will ripen and be discharged during
some subsequent year. Other changes, which it is not necessary
to mention here, take place in the eggs and tissues, but the ulti-
mate result is that the ovarj^ becomes enlarged by the growth
of the ripening eggs and the latter pass into the oviducts which
stand out as milkj^-white and much-branched vessels on each
side of the body.
The spermatozoa develop in much the same manner, but the
generative cells, instead of developing into ei^^s, undergo rapid
divisions, each into a number of minute, active bodies, which
pass into the sperm ducts and gorge them with a white fluid, the
milt, in general naked eye appearance resembling the ovarian
fluid.
SPAWNING.
The act of spawning consists in the discharge of the ripe
generative products into the surrounding water, where fertiliza-
tion takes place. The season in which the oysters spawn dif-
fers very much in different regions, and in the same general
region is influenced by local cbnditions. As a general rule, it
may be said, that spawning takes place earlier in the South
than in the North; and in the same region, in the shallower,
than in the deeper water. Apparently the chief cause of this
fact is the temperature of the water, which becomes warm in
Southern sections earlier than in the north, and in shallow
places sooner than in the deeper.
In Louisiana the spawning soasDu extends from the early
part of April to the latter part of September, while sporadic cases
of spawning undoubtedly occur in every month of the year. In
seasons whi n, for any ro:is()ii. there have lieen conditions which
interfered with spawning at the usual time, it has been observed
that the breeding season may be changed. After a prolonged
spring freshet it is not at all nneommon to find oysters spawning
late in the fall. In the season of 1005 the oysters in Calcasieu
Pass were spawning abundantly in the early part of October, and
in the same year spat were setting very abundantly in the waters
<'f Vennilion Parish up to the last of that montli.
'I'he acre at which oysters become 'capable of spawMin<r varies
12
From "The Oyster." After W. K Brooks.
13
with the locality, but it may be safely said that in this State
the generative products ripen during the tirst year. In the
siunmer of 1U06, oysters in Calcasieu Tass, which were not more
than eight months old were practically all spawning, although
the amount of ripe sexual elements was small in each ease.
The number of eggs discharged by a single female is natur-
ally dependent on its size. It has been estimated that an oyster
of average size produces 16,000,000 eggs in a year, while a very
large individual may produce as many as 60,000,000. The sper-
matozoa, being exceedingly minute, are present in the milt in
inconceivable numbers.
Since there are so many chances that the eggs and sperma-
tozoa will not meet in the water, the reproductive powers of an
oyster bed are not nearly so great as are represented by the re-
productive elements discharged l>.y the breeding oysters. Neither
the eggs nor sperms live long after they have been dischargd
from the body of the parent; so if fertilization is to take place at
all, it must be accomplished soon after the sexual products are
tlischarged. Even when the eggs and spermatozoa do meet and
fuse, the dangers which must be met by the young are so numer-
ous that the chances are that only a very small percentage of
the fry will become permanently attached and go on with their
development.
DEVELOPMENT OF THE OYSTER.
By mixing the eggs taken from the reproductive organs of a
female oyster with the male reproductive cells it is an easy
matter to bring about their union in any small dish of clean
sea water: and their development may be followed under a
microscope. •-
Some fifteen minutes after the ^(sfxfi have been fertilized
(Plate II. Fig. 1), they will be found to be covered with the
male cells. In about one hour the ef^g will be found to have
changed its shape and appearance. It ha.s now l)ecome spherical,
and the clear central portion — the germinative vesicle — is
no longer visible. In a short time a small transparent point
makes its appearance on the surface of the o\:cr^ and increasinir
in size, soon forms a little transfiarent knob — the pole cell.
A second nole 'cell is snon afterward given off. and the egg
14
b'.^cumes peai'-shaped, with the pole cells at the broad end. This
end divides into two parts, so that the egg is now made up of
one large mass and two smaller ones, with the pole cells between
them (Plate II, Fig. 2).
The later development of the embryo shows that even at this
early stage the egg is not perfectly homogeneous, but that the
material which is to give rise to different organs of the body
has already been separated from that which is to form others.
The single cell at the smaller end of the egg is to give rise
to the digestive organs of the adult, while the two smaller
cells are to give rise to the outer wall of the emhryonic body
and all the organs which are derived from it, as the gills, palps
and the mantle, as well as the shell, which is secreted by the
mantle. The two upper cells divide up into smaller and smaller
spherules (Plate II, Figs. 3, 4, 5, 6), until there is a layer of
small cells wrapped around the greater part of the surface of
the single, large, lower cell. This soon divides into a layer of
cells, so that the embryo is made up of two
layers of cells : an upper layer of small cells,
'cells, and a lower layer of larger cells. The upper, small cells
have come from the division of the two spherules occupying
the broad end of the egg in the pear-shiped stage, and are to
form the outer wall of the body. The lower, larger, cells have
come from the division of the single lower spherule of the three-
celled stage, and are to form the digestive tract and its derivi-
tives.
The layer of large cells is seen in the section (Plate II,
Fig. 7) to be pushed in a little toward the upper layer so that
the lower surface of the embryo is slightly concave. This con-
cavity is the beginning of the rudimentary digestive tract.
Soon after the last mentioned stage has been reached, the
embryo undergoes a marked change in appearance. A tuft of
long hairs, or cilia, makes its appearance at one end, and
these cilia begin to lasTi back and forth, thus constituting a
sAvimming organ by means of which the little animal forces
its way to the surface of the water, where it moves about actively
for some time.
The concavity which marked the beginning of the digestive
tract has become deeper, until the edges have almost met around
i'o
tlu' ()l)eiiin>r. So tliat the embryo now consists of two liollow sacii:
the inner one, tlie digi stive trfiet. eoniniunieating with tile exterior
by a small pore — the primitive moutli. and surrounded at all
points except at the mouth by the outer sac Avhich fonns the
body wall (Plate II, Fig. 8).
This stage in development, in which tlie riiil)i-y.. consists
of two hiycfs. the inner foniiiiig tlic di-cstivc tfact which is
enclosed witliiii an outer one wiiich forms the body wall, is of
very genci-al occufiviuH' in llic developmental history of widely
separated groups of animals, and is known as the (jastrula stage.
Some tinie after the free-swinnning stage has been reached,
a small, irregular plate of cells makes its appeai-anee on each
side of the body. These little plates are the shell glaiuls in which
the primitive shells have their beginnings. The shells are sepa-
rate from the first, and during the early development of the
oyster they are synnnetrreal and nearly circular in outline.
After the shells make their appearance, the embryos cease
t.> crowd to the surface of the water, although they are still
capable of swimming about actively. The anterior part of the
body, which bears the cilia, begins to be sharply defined as a
circular pad— the voluni (Figs. 8-11), which serves as the organ
of locomotion during the remainder of the free-swimming life
of the embryo.
The two shells, at first too small to allow the body to be
withdrawn between them, continue to grow, until they become
large enough to cover up or even extend beyond the surface of
the body. By this time muscular fibres have developed in the
body wall. These are arranged so that they can draw the
body and the velum inside the shell. The surface of the body,
which lines the shell in either side, becomes converted into the
mantle lobes and a mantle cavity is formed between them.
The primitive mouth becomes closed during the early stages
of development, and later a new opening, the permanent mouth,
i.' formed on the opposite side of the body from the location of
the primitive mouth. After the formation of the permanent
mouth, the digestive cavity increases in size, and its walls be-
come covered with cilia. The wall of the stomach becomes con-
nected with the body wall a little way behind the mouth, and
another opening, the anus, is formed. The tube which connects
16
the anus with the stomach lengthens and becomes the intestine.
This part of the digestive tract soon becomes very much bent,
upon itself, so that its length is several times the distance be-
tween the stomach and anus. The two sides of the stomach
become folded off to form the two halves of the liver, which
later fuse into one indistinguishable mass.
Up to the time of the formation of the permanent mouth,
the embryo had developed without any increase in size, but after
the establishment of the two openings to the digestive tract, food
is taken and an increase in size takes place rapidly.
When the embryo settles down to its fixed existence, the
mantle on the left side extends beyond the edge of the shell
and secretes a layer of the same material, which attaches it to-
the permanent support.
The velum is resorbed and the organs of the body assume
the proportions characteristic of the adult.
The great practical utility of a knowledge of the develop-
ment of the oyster, is in that it shows the vast number of em-
bryos that are formed at each breeding season, and suggest'i
the feasibility of adopting the method of exposing some hard
bodies on which the young may settle when they have become
old enough to give up their free-swimming existence.
PHYSICAL AND BIOLOGICAL CONDITIONS ON OYSTER
BEDS— TEMPERATURE OF THE WATER.
Oysters live in water of very different temperatures, both-
r.s to the average for the year, and the extremes met at different
reasons. In the Louisiana fields, the extremes met with are not
likely to vary from more than 45 degrees (Fahrenheit) as tho-
lowest to 75 or 80 degrees as the highest. This upper limit
may be exceeded in some places, where the water is very shallow,
during the warmest months of the summer, while in unusually
severe weather in wiiiter the temperature may fall nearly to-
the freezing point in the same lo'calities.
The temperature has an important bearing on the" food
supply of the oysters. When the water is warm, there is a
rapid multiplication of the small plants on which the oysters
feed, and at the same time the vital activities of the oyster
are quickened, so that the growth is most rapid in the warmer-
seasons.
Fig. 1. View of right side of embryo about six davs old. m niniitli • v
vent: /, right lobe of liver; vl. velum. " ' '
Fig 2. Older larva of European oyster, Oatrca lurida. L, shell; h. hinge;
r? and ri, retractor muscles of the velum, vl ; a, stomach ; i, Intestine; am larval
adductor muscle ; b. body cavity. Other letters as in the pre.edinu
». n^'V'- 3. Attached spat of Oatrca virginica. S. shell of spat with larval
shell, L. at the beak or umbo ; p. palps; o. gills; c, diagrnmmatir representation
of a single row of eillla extending from the mantle border lo the mouth; t/i ;
r, radiating muscle fibres of mantle; /, rudimentary tontaoles of mantle border-
M permanent adductor muscle; C. cloaca; ve and au, veiiiricle and auricle of
the heart; ;/. posterior extremity of the gills and Junction of the mantle folds
Other figures as above Compare this figure with PI. I Fig 1
Fig. 1 after W. K. Brooks KIg 2 after Thomas H. Iluxlev. Fig 3 after
John A. Ryder.
18
The temperature of the water probably has a definite rela-
tion to the time of spawning of the oyster. Artificial fertiliza-
tion can be best brought about when the temperature of the
water is from 70 to 75 degrees, and the growth of the embryo is
most rapid when the temperature is a little above these limits,
AVhen the temperature falls below 65 degrees development almost
ceases, and this fact may be the real explanation of the great
mortality among oyster fry when there is a cold rain during the
breeding season,
SALINITY OF THE WATER.
Oysters are found in water ranging in density from 1.002
to 1.025, but the lower densities are always injurious, and usually
fatal if the oysters are subjected to them for any length of
time. It is not possible to suecessfuily maintain oyster beds
in water Avhere the density is less than 1.007 during the greater
part of the time, for even if the oysters are not killed they will
be of poor condition, pale, watery and tasteless. The salinity
over the best beds varies from 1.010 to 1.022 ; the former being
the density over beds in shallow water, the latter being found
only over beds which are situated in M^ater of considerable depth.
It has been suggested that the favorable results which have
been noted from beds situated in brackish water may be due
to the fact that in these instances the water is usually shallow
and consequently warmer. The higher temperature, in so much
as it tends to increase the food supply, being considered as
perhaps of more importance than the salinity.
The apparatus used for determining the salinity of the
water consists of a glass float made with a long, narrow stem
above and with a large bulb below. The bulb is weighted so
that in fresh Avater it sinks the instrument to a point on the
stem marked 1.000.
The stem is graduated to read from 1.000 to 1.031, the fig-
ures representing the specific gravity; that is, they show the
weight of the sample of water, an equal volume of fresh water
being supposed to weigh 1.000. In practice the salinometer floats
are made in sets of three, for convenience in handling. The first
reads from 1.000 to 1.011, the second from 1.010 ot 1.021, and
the third from 1.020 to 1.031. The sample of water of which
19
the salinity is to be determined is plaeed in u jur, or one of the
special eylinders providtd with the onttit and the tUmt havinj,'
been placed in the water, the density of the sample may b<!
read from the scale where the surface of the water touches the
stem. To show the sp«'cilic gravity of the water the number
"1.0" should always be placed before the reading taken from the
scale; thus, if the scale reading' is 10. the specific j;ravity would
be 1.010.
The specimen of water should be taken from near the bot-
tom and may be conveniently obtained by lowcrinfr a corked
])()ttlc or jug to the bottom and then pulling out the cork by
means of a string previously attached to it. After the receptacle
has filled it is brought rapidly to the surface without danger
of the sample being much changed by tlie influence of tlie upper
layers of the water.
TIDES AM) CURRENT.
The tides and currents in any region are important factors
in the growth and cultivation of the oyster. They bring about
the aeration of the water and the destruction of the dead organic
refuse; they have a scouring effect on the bottom and there-
fore clean the clutch: and at the same time are the chief means
for the transportation of the food materials and the young fry.
Stagnant water becomes exhausted in oxygen and also becomes
ioul from the decay of organic matter which it contains. Under
the influence of currents, particularly those of tidal origin, the
supi)ly of oxygen is renewed, and the efl'ete matter dispersed
^(, that it becomes harmless.
On densely crow-ded oyster beds the supply of food would
soon become exhausted unless there were some means of bi-inging
a fresh supply from outside sources. The oysters are inMiioval)ly
fixed on the beds and can take only such food as is l)rought
witliMi r.ach of their cilia, so that the action of the currents in
briii'/iiig llic food-laden water to the bed is of vital importance
to theii- growth.
The genital |)roducts of both the male and female oysters are
simply discharged into the surrounding water. The eggs are ab-
solut( ly iinmotile. while the spermatozoa, or male elements, pos-
sess the power of locomotion to a limited extent oidy. and are in-
caDable of uiovinu very far dnrintr tlie short time they remain
20
active. On densely crowded beds it is very likely that a good
many of the eggs would become fertilized in the absence of any
currents; but where the oysters are scattered this proportion
would be exceedingly small. It is a well-known fact that in
regions removed from the influence of currents the reproductive
capacity of tlie beds is much lower than on beds that are exposed
to active currents.
After fertilization has been accomplished the currents are
the chief agents in the dissemination of the fry. The fry is a
free-swimming organism; but its powers of locomotion are not
sufficient to carry it any great distance from the point of its
origin. The wider the distribution of the fry the greater will
be the chance that any one of them will have an opportunity to
come in contact with some hard body to which it can become
attached when it is ready to settle down to its fixed mode oi'
life. Even strong currents do not seem to prevent the fry from
settling on any suitable object which may be exposed in the
water, and frequently where the current is the strongest the
set of spat will be heaviest.
SILT, MUD AND SUSPENDED MATTER.
A large amount of sediment in the water is a great draw-
back to the successful pursuit of oyster culture in any region.
The organisms which make up the food of the oyster are found
suspended in the water, and, of course, this material 'cannot be
looked upon as disadvantageous. An ideal condition of the
water would be where there was an abundance of the food
organisms without any inorganic matter suspended. The pres-
ence of sediment which will be deposited on any hard body on
the bottom makes the planting of clutch a very uncertain un-
dertaking, and is also likely to cause a great loss among small
oysters which have been planted for seed.
An organic slime is sometimes formed on shells and other
hard bodies in the water. This deposit is found most frequently
on the shells of a bed which is exposed to the air for a part of
the time each day. as in the case of the reefs of "coon" oysters
that are fo^iiid in the marshes alono- the coast. The slime is
usually made np of a growth of some of the small algae auJ
forms an effectual barrier to the setting of spat on the shells
which it covers.
21
DEl'Tll OF WAT Eli.
The vortical raiitre of oyster beds is troin the shore line to
some lifteeii fathoms of water, althou^'h the number of beds iu
such deep water is comparatively small, and they exist only
when they have been made artificially. The conditions for
growth are usually more fj^vorable in the shallower waters and
the «j;reater deptLs are resorted to only when the bottoms nnder
shalh)w water have been taken \ip. In the deeper water there
is less likelihood of obtaining: an ahiuulant set of spat, and f )r
this reason they are less adapted for planting; with clutch.
In some of the deep channels of the baj^ous on the coast
of this State natural reefs oi oysters are found in from twenty
to forty feet of water, and under the same conditions of salinity
and food supply, there is no apparent reason why planted beds
should not do as well at the same or greater depths.
The shallower portions of the gulf out to a depth of five
to ten fathoms are practically unexplored from the standpoint
of oyster culture, and no definite statement can be made con-
cerning the practicability of plants in the gulf further than to
say that in the places already studied the conditions seem to
le favorable wherever a sfahlr hotfom can he found.
WK.ITHIJU <'<).\nir/<).\S^ST()li'MS. h'A/Xs. ]
(iales rarely have any inHuenee on llie beds in deep water;
but in shallow water, and particularly where the bottom is
made up of somewhat sandy material, the amount of dwmage is
sometimes very great. The waves stirred up by the heavy
winds may tear the beds of oystei-s to pieces, casting the living
oysters on the beach or b;irying them so that they are stifled and
the bed practically destroyed. In exposed regions where the
bottom surrounding the oyster beds is verj- muddy, the waves
stir up the surface layers of soft mud so that the whole bed
may be covered with a deposit of sediment sufficient to kill all
of the aysters. If the currents are very strong the greater part
of this deposit may l)e washed away l)efore the oysters have
perished; but in the jibscnce of such furrenls the deposit is
sure to be fatal. In storms of less severity, when the ])ottom
i.-; not disturbed enough to do anv dajiiage. immense masses of
22
sea weed are sometimes brought onto the oyster beds, covering
them to a depth of several inches. The masses of bruised, and
often decaying, sea weed will serve to stifle the oysters almost
as effectually as the covering of mud.
The fry are more easily affected by the weather conditions
than are the adults. It has been recorded that they are killed by
thunderstorms, by cold rains, and by sudden falls in the tempera-
ture, so that the prevalence of stormy weather during the breed-
ing season may have a great effect on the set of spat that will be
secured in any year.
In some especially severe winters ice forms over the oyster
beds in the shallow, brackish waters, while over the deeper beds
the temperature is lowered nearly to the freezing point. Some
of the beds that are in very shallow water, or which may be
exposed at low tide, are very much damaged. In the deeper
water there is little danger that the oysters will be destroyed;
but they may become unfit for the market so that their value
is lost for some time.
CHARACTER OF THE BOTTOM AS AFFECTING THE
DISTRIBUTION, GROWTH AND CONDITION
OF OYSTERS.
The character of the bottom of any area determines, more
than any other physical factor, the abundance and quality of the
oysters that may be produced there; and, indeed, this factor
may determine whether or not oysters can grow in a certain
locality without artificial conditions being brought to the aid
Ox the natural ones.
In the formation of any natural reef, except in a few cases
M'here the reef is built up on a sandy or gravelly bottom, tne
area covered by the reef is the only hard bottom in the vicinity,
and the growth in size of the reef takes place by the breaking
off of shells from the body of the reef. These fall to the soft
bottom at the sides of the reef, the first ones sinking below the
surface of the mud and disappearing. As this goes on for some
time, it comes about that finally some of them are kept above
the deposits of sediment and on these the young oysters are en-
abled to find a place of attachment, thus extending the boundaries
of the reef. "When this new portion of the reef is once above
23
the luud, and there is uo longer any danger that the oysters
will be covered' by sediment, the elevation of the new area is
quite rapid. The tirst steps in the process are the slowest, as
the reef is at first composed only of a very few oysters. These
are attached to some hard body that has remained above the
mud long enough to enable the oysters to reach a size when
there would be no danger that they would be themselves covered
up and stifled. Of the total number of such small beginnings
i*^ is certain that only a very few come to be developed into reefs
of any size, while by far the greater number of them never
cover more than a few square yards at most. In regions where
the salinity of the water, and the abundance and distriDUTiou
of the food organisms, is such that the oysters would grow very
well, the number, size and location of the reefs, as well as the
quality of the oysters growing on them, depends to a great ex-
tent on the character of the bottom. In such a locality it is
usually found that the bottom in all places where it has not been
artificially hardened by the formation of reefs, consists of very
soft mud and the area bearing oysters is insignificant when
compared with the whole territory in question. It has also
been observed that the oysters making up these natural reefs
are, almost without exception, of very poor quality, long and
irregular in outline, very narrow, and with little depth between
the shells. Usually they will be found attached in clusters to
some shell of an older generation which is mostly below the sur-
face of the mud. At the time when the oysters of the last
generation settled down to their fixed life, the shells of their
parents afforded the only pla'oes for attachment in the vicinity,
and by the growth of the younger oysters the older ones have
been covered up so that they could not get an abundance of
food. Besides, the sediment settles out from the water as the
surrents are slowed down by the shells of the younger generation
rising above their parents. If one of these clusters is examined,
it will frequently be possible to count from three to seven gen-
erations in a single cluster, each generation being attached near
the upper end of the shells of the preceding one. This charac-
teristic shape of the oysters from a natural reef which has never
been M-orked is due to the crowding that takes place among the
f)ysters in the struggle to keep the upper, open ends of the
24
shells above the mud and in the position where it Avill be pos-
sible for them to obtain the most food. On this account thosfr
individuals that are nearest to the surface of the reef in any
given generation will be the largest, Avhile those that are at-
tached nearest the mud, where they are perhaps covered with
sediment for the greater part of the time each day, will show the
result of their hardship in their smaller size and poorer condition.
In places where the bottom is generally hard, and there is.
present some material to serve as a place of attachment for the
fry, it will be found that the oysters are not crowded together
in dense clusters, as they are over the soft bottom, and in this
case there will be a very noticeable ditference in the shape and
condition from that of those on the crowded reef. Instead of
being long, narrow and thin, they will be much more rounded
and deeper between the shells, so that the bodies of two oysters
of the same length of sTiell taken from the different reefs will
differ very much in volume.
While the presence of a very soft bottom on any area has
a tendency to make the oysters growing there of poor quality, and
to restrict the amount of surface covered by the reefs, it fur-
nishes, on the other hand, the most favorable conditions for the
growth of the minute plants which make up the food supply
of the oyster. Since the restrictions imposed by the softness
of the bottom can be overcome by artificial means, a region
where the bottom is generally soft offers the best opportunity
for growing oysters successfully. The means of bringing about
the changes necessary for the preparation of a soft bottom to
receive seed oysters, or to start a plant by affording a place of
attachment for the spat, will be discussed under the head of,
cultural methods.
FOOD.
The food of the fry and young spat consists of bacteria
and some of the protozoans, the most minute organisms known.
Dr. Ryder describes the food found in the stomachs of
newly attached spat as follows:
*"Many of the food balls found in the stomach of the re-
cently attached spat will measure less than .001 of an inch
in diameter. The cavity of the little creature's stomach measures;
* Hyder, .T. A.. Report T'. S Fish rommission. ISS.^. pp. 3S73SS.
25
6.
Outline (liawiiiKS of tlio most important constiiii.'
in the watPi-s ol" tlic Louisiana roast.
All of tlip tiuuros ai-p drawn to tlip same ma;;nilii
Fk;. 1. E II i)ihI incus.
Fir,. 2. CiivcinodiHcnu.
Vic. :\. I'Uuionifjma.
Vui. 4. I'iiiniilnria.
Fio. .'. yariciila.
Fui. 6. Mcluniia
IS of tlie food of oysters
26
only .005 of an inch. Yet in this minute digestive cavity the
food is actually found rotating in the form of minute rounded
or oval bodies, which are kept in motion by the action of the
cilia which line the stomach. That these bodies must have
been of about the same size as when they were swallowed and
as when seen rotating in the stomach, is evident from the fact
that the young oysters, like the adults, are wholly without
teeth or triturating organs of any kind.
This minute kind of vegetable and animal food is found
more or less abundantly in all sea water, and is especially abund-
ant during the spawning season, when the disintegration and
decomposition of all kinds of minute organic debris floating
in the water is in rapid progress, owing to the prevalent high
temperature of the air and Avater. It is, therefore ,probable
that very few otherwise suitable localities exist where it is not
possible to find an abundance of the proper food for the young
oyster during the early stages of its growth."
The food of the adult oyster, in common with that of the
clam, mussel, scallop, and other molluscs of the same type, con-
sists almost entirely of minute plants. By far the greater num-
ber of these food forms belong to the class of plants known as
Diatoms. In the stomach of an oyster there will often be found
other materials besides the plants just mentioned. At the time
of spawning of the oyster there will be large numbers of their
eggs, and at all times some of the very small animals ; but when
a record of the stomach contents is kept for an extended period,
it will be found that the diatoms make up by far the largest
and most important part.
All diatoms are enclosed in a flinty covering made up of
two valves which fit together like the two halves of a pill box.
The markings on the shells are characteristic ,for each of the
difl'erent forms, and thus allow their ready identification in
the stomach contents of the oyster even when nothing but the
empty shells remain.
Diatoms occur in immense numbers in the waters of the
ocean, in the brackish waters near the shore, as well as in the
fresh Avater of ponds and rivers. The kinds of diatoms found
in these different localities differ very much in their characteris-
tics, and the forms on which the ovster feeds are those that are
27
ior the most part v-onliiu'd to llie coiiii)arativt'ly shallow, brackish
water ak)ng the shore. As previously mentioned, the diatoms
are most abundant in localities where tliere is a soft, muddy
bottom.
^lost of the diatoms are motile, and during the day, under
the influence of the sunlight, they migrate from the bottom
toward the surface of the water, settling down to the bottom
again at night. During the periods of migration they are the
most abundant in the water above the oyster beds, and it has
been shown that the oysters procure the most of their food at
this time. During the night, when the diatoms are at the
bottom, they undergo repeated divisions, each into two new
individuals, so that the numbers are ver\' rapidly increased.
The manner in Avhich the oyster obtains its food has been
previously mentioned in the chapter on anatomy.
While there are several forms of diatoms always found in
the stomach contents of oysters from any locality, a few of
these are so much larger than the others that in order to get
an adequate idea of the richness of the food supply it is neces-
sary to determine the numbers of the larger forms only.
The warm season in the summer and fall is the time when
the diatoms are the most abundant and when the greatest growth
of the oysters takes place. The fact that the oysters do not
usually get fat until rather late in the fall is because earlier
in the season their energies are expended in the production of
the sexual products, and the fattening takes place as soon as
this drain on their vitality is over.
ENEMIES.
In all stages of its development the oyster is preyed upon
by numerous, and more or less destructive, foes. In the adult
condition the presence of the rather thick, limy shells affords
protection against the weaker enemies; but in the earlier stages
of its growth it is entirely without any means of protection and
is preyed upon l\v many small forms. The miinite eggs and fry
are swallowed in immense numbers by the adult oysters, other
molluscs, worms, sponges, hydroids, etc. Fishes, like the men-
haden, which get their food l)y straining out the minute particles
from the water, doubth^ss cDiisnnie larL'o nuni])ei-s of the free-
swimming young.
28
After the attaehinent of the spat, other enemies, both active
and passive, wage a never ceasing warfare on the oyster; so
that the number of eggs that give rise to adult oysters Avill be
enly a small proportion of the whole number fertilized.
The oyster beds of the Louisiana coast are particularly for-
tunate in their freedom from some of the worst enemies of the
oyster that occur in the more Northern waters-. The starfisk
by far the most destructive enemy, is, so far as any records and
observations show, entirely absent from the oyster beds of this
coast; although some of the small starfish are frequently taken
in the gulf in water from two to four fathoms deep. This form,
however, is not the same as the one that does the damage on
the Northern beds, and in a great many specimens examined,
the only food found in the stomach consisted of one of the srr..,.!!
clam-like molluscs that is very abundant in the shallow waters
of the Gulf.
The oyster drill {TJrosalpinx cinerea) is also absent from
the oyster-producing regions of tliis State.
Several of the large marine snails, or conchs, are found
quite abundantly along the coast; but so far as can be learned
they do no appreciable amount of damage to the oyster beds.
A boring sponge (Cliona sulphurea) is present in some
sections of the oyster fields; but it has not been found in the
later stage of its development except in a very few instances.
In the younger stages this fonu bores into the outer layers of
the shells of living oysters, as well as in any empty shell, forming
intricate systems of burrows from the openings of which the
orange-colored sponge protrudes in little finger-like processes
one-eighth to one-half an inch long. In this stage the sponge
has been found on the oyster beds, both natural and artificial,
in many parts of the State.
In the later stages of its development the sponge grows up
into a larffe mass which covers the outer surface of the shell or
oyster, and on this account makes it impossible for the latter to
procure food and oxygen, so that at last it finally dies or be-
comes so emaciated that it is of no value for the market.
In the younger stages the burrows are of no particular harm
except that they tend to weaken tlie shell, and may also detract
from the appearance of the oysters when they are to be sold as
29
*'sll('ll stock.' ( »ii till- ()l(l ivefs this sj)<>uirt; is nm; ot llu- ai-tivc
disintcirratiiiL:- aiiciits that hasc bi'niiyht about the i-a[)id dis-
apix-araiicc of the shi-lls.
( HAB8.
Some of the hirgi-r crabs, especially the stone crab {Menippe
lutrciiiaria) do considerable damage to the younger oysters by
breaking the thin growing edges of the shells and then extracting
and eating the body. "While crabs are present on the oyster
beds in all ot the Louisiana waters, the amount of damage
done by them is comparatively slight.
The greatest funount of damage done by any of the living
enemies of the o\ster is due to the attacks of the drum fish, or
black drum. The oysters on the natural reefs, and for that mat-
ter on the cultivated beds, are not troubled very much, because
the oysters grow with the thin, sharp edges of the shells upper-
most, so that there is no opportunity for the fish to attack them
without having its jaws severely lacerated l)y the knife-like
edges of the shells.
After the oysters have been in one place for some time
they become covered with a thin layer of sediment so that there
is nothing in tlieii- appearance to call particular attention to
them; l)ut on the otlier hand, when the oysters have been
changed from one jjlace to another they stay on the top of the
mud for sonie time and are very prominent objects on the
bottom.
At the time when oysters which have hei-ii taken up
and culled arc put down again, either to wait foi- the comple-
tion of a load, or when working over a plant, they are especially
liable to be attacked by the fish, fis now. they are V( ry ea.sy to
get at becau.se when they are separate there is not the incon-
venience to the fish that theiv is when all the sharp edges of
the shells ai'e close tog<'ther.
Tn some parts of tlu- State the fish have lieeii so bad at
certain times that a whole load of oystei-s. tlie results of a vveek 's
woi-k. would be lost in a single niirht.
In most sections wheiv the fish ai-e at all bad, if is custo-
niary to have a snudl bed tliat is ])rotected ])y IxMiig fenced in
with a sort of barricade made of stakes or boards put down
30
close together so the fish cannot get at the oysters, but not
close enough to keep the water from circulating freely. As soon
as the oysters are taken from the reef and culled they are put
inside this enclosure to be kept until they are to be sold.
SKATES OR RAYS.
In some parts of the State, espe'cially about the lower end
of the delta, the oyster men report that some of their beds have
been destr9yed by the depredations of some of the large rays,
which clean up an entire bed in a short time. So far as can be
learned, the attacks of these forms is limited to the delta region,
and there they are not very common. Unlike the "drum," these
fish attack the oysters on the natural beds so that to guard
against their destroying the beds it would be necessary to fence
in the whole area where the oysters were growing.
BORING CLAMS.
A boring clam (Martesia striata) is commonly found in the
shells of living oysters from many parts of the coast. This
form bores into the shell of the oyster when it is young, and
as it increases in size, enlarges its burrow, until in many cases
it breaks through into the mantle 'cavity of the oyster. While
these clams are not of sufficient abundance to be of very much
account, and do not of themselves destroy the oysters, their
presence in the shell tends to weaken it and thus make the
oyster more susceptible to the attacks of the enemies that crush
the shells. In the cases where the burrows of the clam reach
through the oyster shell into the mantle cavity, it becomes neces-
sary for the oyster to secrete a new layer of nacreous material
to cover up the opening, so that there is an extra drain on
its vitality.
Besides those enemies which destroy the oyster directly for
their food, there are other destructive agents that do their dam-
age only indirectly; by cutting down the available supply of
food organisms, or by causing an increase in the deposition of
sediment over the oyster bed.
MUSSELS.
"Mussels are frequently found in abundance among the oys-
ters, both on the natural reefs and on the planted beds. The
mussels are attached to the oysters by means of a bundle of
31
fibers (the byssus) formed by the hardening of the secretions
from a ghmd in the foot, and they never change their position
after they have settled down from their free-swinnning stage.
Sometimes the mussels are so numerous that they fill up all the
spaces between the oystei-s and cover the entire outer surface
of all the shells.
The mussels do no violent damage to the oysters; but since
the food of both fhese forms consists of the same kinds of
diatoms, it follows that the more mussels there are on a given
bed, the less food there will be for each of flie oysters, and the
less chance for the food materials being brought to the open
ends of the oyster shells, as the mussels have the first chance
at the Avater to strain out the food.
TIYDROIDS.
The presence of hydroids is detrimental to the oyster bed
in that they keep down the amount of food organisms that can
be available to the oyster, not as in the case with the mussels —
because they feed on the same plants, but because the hydj-oids
grow up above the ends of the oyster shells and form a sort of
a strainer which tends to keep back some of the food which
would otherwise reach the oysters. Besides cutting down the
food supply, the hydroids collect a great amount of sediment
from the water and thus tend to 'cover up fhe oysters and inter-
fere with their breathing as well as Avith their food supply.
ALGAE.
Several forms of marine plants, of the class known as algae
sometimes do considerable damage to the oyster beds, both by
keeping down the available food supply— so that the oysters do
not get fat: and because their presence on the shells of an
oyster has a detrimental effect on the market value. It is very
dififieult. or practically impossible, to clean off this growth so
that the oysters may be used for shell stock, while if they are
1o ])e used for canning, the presence of the alga gives the jneats
a disasrreealilo flavor when they have been steamed.
BUCEPHAIvUS.
The presence of Bnccphahis, a parasitic worm, has been re-
])orted from the oyster beds of Louisiana on several occasions.
In the adult stage tliis worm is parasitiv^ in some of the fishes
32 -
that live in the waters along the coast, one of the young stages
being- the form found in the oyster.
When an oyster is infested with this parasite the visceal
mass Avill have an appearance very similar to that of an oyster
laden with well-developed sexual products. On a more careful
examination it will be found that the "milky" appearance is
due to the presence of immense numbers of minute tubes that
ramify throughout the visceral mass. If the body of the oyster
is cut or pulled to pieces, the edges of the fragments separated
will have a "fuzzy" appearance as if the entire mass was com-
posed of small hairs.
In all cases of infestation by this form that have come to
the notice of the writer, the proportion of the oysters infested
has been so small as to be negligable from a practical standpoint,
and in more northern localities where the presence of this para-
site has been known for years the damage has seldom been of any
account.
DESTRUCTION BY FRESHETS AND RECOVERY.
In the greater part of the oyster-producing area of this
State, the most damaging destnictive agent is the fresh water
\rhich from time to time breaks away from natural restraints
and for a greater or less period of time makes the water over the
oyster beds so fresh that the oysters are either killed outright, or
made so poor that they are useless for market for some time.
The damaging amounts of fresh Avater may come from the
smaller rivers at the time of the annual spring freshet, or iu
the eastern parishes, from breaks in the levee of the IMississippi
River. In the former case the freshet is likely to be more pro-
longed and to be destructive over a greater area. In the latter
case the results are likely to be very severe near where the break
occurs, Avhile the area concerned is not usually so large.
The destruction from the spring freshet is of pretty regular
occurrence, more or less damage being done in some part of the
State each year ; while breaks in the levee have been of compara-
tively rare occurrence, and when they do come can usually be
controlled more than the freshets that depend on the heavy rain-
fall. The result is the same from either cause, large areas of
oyster-producing bottom being practically denuded of their
growth.
33
Besides the fact that the oystei-s on a bed are destroyed, it
sometiiues hui)i)ens that a great amount of sediiinMit is dei)o.sited
on the beds so that the shells of the oysters tliat have been kilhid
are either covered up by the deposit, or become so foul that they
no longer atford a good place for the spat to become attached
and thus the chance for the restocking of the bed is done away.
Where the destructive freshet has come from breaks in the levee,
the current is usually so strong that there is no deposition of
sediment on the shells up to the time of the closing of the break.
In such cases, the shells being in very good condition for the
reception of the spat, it has been observed that tliere was an
unusually heavy set; and this has often been attributed to son)e
unknown effect of the unusual mixture of fresh and salt water.
The drainage canals, which have become so munerous in
recent years, have served to make the distribution of the rain
water very different from what it was formerly. The rain water,
instead of having to drain slowly through the sAvamps to reacfi
the bays, now has a ready avenue of escape through the canals
and reaches the coast in much larger volumes a short tim-.'
after each heavy rain. The effect of the increased flow of fresh
water can be noticed in many places where formerly productive
areas are now too fresh to admit of the groM'th of oysters.
The changes in the drainage that has been attendant on the-
cutting oft' of the forests in some of the coast parishes have
entirely altered the nature of some of the enclosed bodies of
water so that, where there was formerly good beds of oysters
there are at the present time nothing but dead shells. Avhile in
other places where there were no oysters, reefs have started natur-
ally or the bottom has been utilized for planting.
In a good many sections th? destruction of the beds by
freshets becomes a matter of chance and a bed may be productive
for a number of years without any damage from freshets, then
there will follow a period when it will be imp()ssil)le to grow
any mature oysters on the bed. In other loealities there is always
a good set of spat, but before these have had time to develop into
marketable oysters, the beds are a<jrain destroyed, or at least de-
pleted, so that it is no longer profitable to work them. In the
latter instance the beds might be utilized to grow young oysters
for seed : but in the absence of such an industry there is prae-
tic:illv notliiiiii tli;it can Ix' done with an area of this sort.
34
In order to definitely settle the question of the availability
of any particular area for planting oysters, it would be necessary
to have a knowledge of the liability of the occurrence of destruc-
tive freshets, and this knowledge could be obtained only by hav-
ing a series of records extending over a number of years showing
the frequency and the amount of damage done by the freshets
at each occurrence. Having this knowledge, there immediately
arises the supplementary questions: What are the chances of
the recovery of the beds, and how much time must elapse be-
tween the destruction and the time when the beds will again
become profitable? The answer to both of these questions will
depend to a great extent on the location of the beds in regard to
their relation to the other beds in the same locality, and to the
nature and strength of the tidal currents in the region.
If the destruction has not been complete, the chances are that
there will be enough breeding oysters left to furnish the spat
necessary to restock the beds, and if the currents are favorable,
there is every likelihood of there being a good set of spat, as the
shells will usually be in good condition to afford a place of at-
tachment. When, as is usually the case, the destruction has taken
place just before the breeding season, there will not have been
time for a very heavy deposit of sediment, and conditions will
be favorable for the * ' set. ' '
Where practically all of the oysters on the reef were killed
and where the freshet was local in its effect, the set of spat will
depend to a great extent on the direction and strength of the
currents. The free-swimming fry of the oyster, while it is in-
capable of being carried very far as a result of its own activity,
may under favorable conditions be carried for long distances
by the currents. On this account it will be found that in any
body of water where there are numerous beds or reefs, unless
the water is very quiet, there will be an abundance of the em-
bryos moving about to settle down wherever there is a hard
body to afford them a proper place for attachment. In actual
experience it has been observed, that under conditions not espe-
cially favorable for the transportation of the fry, the set of
spat was nearly as abundant five miles from the breeding oysters
as within one mile of them — and over the whole area the set wa.-?
as heavv as is se'eured on the average bed. In some of the larger
35
bays oil the coast, where there are no very strong currents, except
those caused by tlie action of the wind, oysters are found growing
on shells and other lutrd bodies in every part of the bay, where
they may be separated from any extensive reef by a distance of
several miles.
The time necessary for the recovery of a bed or reef that
has been destroyed by freshets will vary to some extent in dif-
ferent parts of the State; but as a general statement, it seems
safe to say that there is every reason to believe that witliin two
years from the time the spat become attached, the greater num-
ber of oysters on anj- bed will be large enough to be sold with
profit. Records of the known growth of oysters in Calcasieu
Pass ,and on planted beds in other sections, where the age of
the oysters oould be definitely known, have shown that an aver-
age length of between three and four inches may be expected
as the result of the first year's growth, while at the end of the
second year the length will be more than five inches. On one
planted bed, visited by the writer after the shells had been
down for about fourteen months, a large number of the oysters,
roughly estimated as one-fifth, were being saved for market,
while all of the others would undoubtedly reach a market size
-well within the limit of two years.
DESTRUCTION OF THE NATURAL REEFS.
Until a comparatively recent date almost the entire supply
of oysters was drawn from the natural reefs and such was their
abundance that the supply was thought to be inexhaustable. The
fallacy of this opinion has been demonstrated again and again,
and now in this State., in common with all the other oyster-pro-
•ducing sections of the country, the most of the natural reefs
have been reduced to such a state of depletion that they may be
considered extinct from a commercial standpoint, since they no
longer produce enough oysters to make it profitable for one to
work them.
In many cases this result has been brought about so gradually
that there has been a great deal of question as to the causes of
the failure of the supply. In other instances the destruction
has taken place so recently ,and so rapidly, that there can ho no
36
doubt as to the cause. In practically every case, except when
leausecl by fl'eshets, the destruction has been brought about by
excessive lishing.
The reproductive capacity of the reefs was in a state of
nature sufficient to maintain the life of the bed and eprhaps allow
an increase in size from year to year ; but the excessive drain on
the beds necessary to supply the increasing demand for the
oysters soon went beyond the reproductive capacity and the
beds beagn to deteriorate.
Even after the enactment and partial enforcement of laws,
looking to the protection of the oyster beds the destruction con-
tinued under the guise of taking seed with whieh to establish
artificial plants. In this case the seed included everything that
was brought up from the bed by the tongs, shells and larg-3^
oysters, as well as the small ones which by their growth and im-
provement in condition were expected to make profitable the
artificial culture.
By the removal of the shells with the oysters, all chance for
the recovery of the beds was taken away, because even though
enough breeding oysters to furnish an abundance of spat were
left on the beds, there would be no place for these to become
attached as the whole upper surface of the bed had been removed
in taking the "seed."
During the oyster season, Avhen the oysters were being taken,
for market, it was frequently customary to leave a part of the
load unculled on the deck of the boat and to cull this part of
the fare after the boat had started for the port where the oysteri.
were to be sold.
This practice, more than any other, was particularly de-
structive to the oysters, as the greater part of the eullings thrown-
from the boat during the journey to market would be certain
to fall on unsuitable bottom and be lost, without their having-
been of any use to insure an increase in the number of oysters-
in the region, as was the ease when they were taken for seed.
When the reefs had been reduced to a statet so that they were no
longer able to supply young oysters to offset the drain caused
by fishing, disintegration took place rapidly under the action
of the waves and the attacks of the boring animals that are so-
abundant in the warm waters of the Gulf coast.
37
At tlu' present time there may be found many places where
the former presence of a hiry:e reef can be detenu. nod only by
the fact that there is a hard substratum uuder several inches of
mud. In other places, where there were extensive reefs not
many years ago, there is now nothing to distinguish the area
<3xeept that a few scattered, and very much worn, shells may be
found.
The protection of the reefs from destruction by over-lishing
is the most difficult problem that has to be met by the enactment
of legislation for the protection of the oyster industry. Laws
restricting the fishing season to certain periods of the year have
proved ineffectual, since the destruction of the reef will take
place as certainly as the result of ten men fishing for one month
as of one man fishing for ten months. When the source of supply
is a common possession, like the natural oyster reefs, each person
working thereon attempts to get as large a share as possible of
the available supply, and the futun^ productiveness of the reef
is left to take care of itself.
As a result of this system of fishing it frequently happened
that all the marketable oysters would be removed from a bed
within a few days, or weeks, from the beginning of the fishing
reason. AVhen such a result has been brought about within a
few weeks, the protection of the reefs during the breeding season
is of little use if there are few breeding oysters and practically
no clutch to which spat might become attached— although present
in abundance.
In some sections, the presence of large reefs of "coon
oysters" that are not fished for market, tends to keep up the
supply of breeding oysters, so that if there is any suitable clutch
the reproduction of the beds is provided for.
INCREASE OF OYSTERS BY. ARTIFICIAL MEANS.
In all of the oyster producting States the supply from the
natural reefs has become so greatly reduced that the depend-
ence for the annual catch must, for the most part, be placed in
the product from the planted beds. Tender the old conditions
when every one had the .same right to fish on any rcf. there
were no inducements for their prosorvntion -. bnt .mi the other
f?.^
Oyster shells with miderate growth of spat attached. The small oysters
will heconie densely crowded as tkey increase in size and poor, misshapen in-
dividuals be produced. (Natural size.)
39
hand each fisherman was inten steel in ijettin^ the greatest
amount of oysters possible before the supply was depleted.
When one hcd was clciuied up another was resorted to, until
the best oystei-s had been taken from all the reefs. In this
way the beds were being constantly depleted without any provi-
sion being made for their restocking, and the supply of oysters
were reduced from year to year. No serious thought was given
to the question of artificial means for increasing the supply of
03'sters in any region until there was appai-ent danger of the
supply from the natural reefs.
As is always the ease when any natural source of income
and gratification has reached a state of depletion so that there
seems to be danger of the product being denied, there was at
once great activity in the line of experimentation looking to
The discovery of methods to make good the loss which had been
'orought about through carelessness and ignorance. In this in-
stance it was found that the necessary remedies were of easy
{ipplication and the results were such as to assure a supi)ly much
in excess of anything that could have been expected under
natural conditions. By the use of artificial methods the oyster
beds were extended into the water of nnich greater depth than
tliat in which any of the natural reefs were known, if indeed any
existed at the greater depths. By establishing in a short time,
by the use of cultural methods, conditions which under natural
causes alom- would have been centuries in cojiiing about, it has
been po.ssible to change the entire aspect of the oyster indu.stry.
Instead of falling off each year the production of oysters i^
steadily increasing, while considerable sums of money are
turned into the State treasuries as the result of leasing the
bottoms to fiersons engaged in oyster .-"ulture.
The means which are used to assist nature in bringing
about ail inci-ease in the production of oysters will, of necessity,
differ to some extent under the influence of local conditions: but
in general it may be said that the success of the artificial meth-
rds depends on modifying natural conditions in such a manner
ap to bring about one or several of the following results:
1. An increase in the number of the eggs successfully
fertilized.
40
2. An increase in the surface available for fixation, and
thus a consequent increase in the number of spat which will
become attached.
3. The utilization and salvage of the spat which woiild
otherwise perish under natural conditions.
4. A decrease in the liability of attack from enemeis.
5. The utilization of otherwise neglected bottoms and food
supplies.
Of these results, the first and fourth may be brought about
without directly causing any change in the other conditions. The
employment of any methods that will bring about any of the
other results will be found to fulfil the requirements for two or
more of them at the same time.
The usual methods practiced in this country are extensive
rather than intensive, and methods that would have for their
aim the increasing of the number of the eggs fertilized in a
given region are not such as would appeal to the American
•eulturist.
In general the results mentioned above are brought about
by the use of some method of "planting." This consists of
either transferring the small oysters to some place where the
conditions are more favorable for their growth than on the
reefs from which they were taken; or in exposing shells, or
other hard bodies, to offer a place of attachment for the fry at
the time when they are ready to settle down to their fixed
mode of life.
The oyster reefs in any body of water occupy only a com-
paratively small portion of the available bottom. An examina-
tion of these barren areas will show that the physical conditions
are the same here as on the reefs, with the single exception of
the character of the bottom. Usually the bottom between the
reefs is very soft, so that the application of some hardening
agent will fulfill all the requirements mentioned above.
The different steps in the usual methods will now be taken
up more in detail.
41
PLANTING OPERATIONS— GENERAL CONSIDERATION.
In the early days of oyster planting it was cnstomary to
make the plant, whenever possible, on bottom that had been pre-
viously occupied by a natural reef. By this means it was
thought that the best bottom in the region had been secured and
that the venture would be certain to give good results, since it
was known that oysters had grown well in the same place.
Usually also these areas afforded the only bottom that was oi
sufficient firmness to bear up the seed in the quantities ordi-
narily planted. When the places where there had been natural
reefs were all taken up it became necessary to resort to other
areas where the conditions were not so well known and where
the success of the undertaking was more problematical.
The success of any plant made in a new region will depend
to a great extent on the physical conditions prevailing in the
locality, these should be carefully studied before any extensive
operations are begun.
The temperature of the water, one of the important factors
in a general consideration of oyster culture, may be safely
neglected in a consideration relating to the Louisiana fields
alone, where the temperature of the water is constantly within
the limits favorable to the growth of oysters.
The salinity of the water is always an important factor,^
and in these waters the record of the salinity should, if possible,
extend over the period in the spring when the lowest salinity
is to be expected. The salinity should be above 1.007, and it
should be definitely determined that there will be no extended
period when the salinity will fall below this point. While oysters
should not usually be planted in water of which the salinity is-
over 1.023, this consideration does not apply to the Louisiana
territory, for it is very seldom that the water, even in the Gulf
at several miles from the shore, has a salinity higher than
this figure.
The success of a plant, other things being favorable, may
depend on the direction and strength of the currents in the
water in the vicinity. The area actually covered by the oyster
bed has usually very little to do with the production and main-
tenance of the' food supply. Thp patHios of barren Ixtttoni be-
42
tween, and in the vicinity of the beds, furnish the prineii)al
breeding grounds for the diatoms which make up the food sup-
ply of the oysters, and the distribution of these organisms de-
pends almost entirely on the currents. The fact of the depend-
ence of the distribution of the food on the currents of the water
may explain why one area will support an abundance of oysters,
while on another close by, the oysters will never grow rapidly
and will always be in much poorer condition.
In order to assure an abundant supply of food material it
is usually best to avoid a region where the bottom is generally
hard; that is composed of sand and gravel. The condition on
such an area would be excellent for catching spat and would
require no preparation of the bottom ; but it has been found in
practice that growth is slower on sandy or gravelly bottoms
and the oysters are not as likely to get fat in the fall.
The sort of bottom which fulfills most nearly the require-
ments for planting by either method is where there is a firm
substratum overlaid with a few inches of soft mud. On such a
bottom there is no danger that the oyster will sink deep enough
to be in danger of being smothered, while the surface mud wll
assure an abundant and continuous supply of food organisms.
In practice the abundance of the food supply, as well as
other conditions, is usually determined by making experimental
plants to determine the best growing and fattening grounds.
This melhod, while giving a demonstration that is certain and
one that will be accepted by the practical culturist in prefer-
ence to the results of a preliminary biological survey, is vern
wasteful of time and capital and sJiows nothing that could not
have heen determined just as accurately and at much less cost
by scientific methods.
PLANTING WITH SEED—PREPARING THE BOTTOM.
When the areas to be planted have been located and marked,
the fil-st step is the preparation of the bottom. Before any of
the steps in the planting, properly speaking, are begun, the
bottom should be carefully gone over with a dredge and all
debris removed. If the bottom is hard or if there is a firm
substratum an inch or so below the surface, no further prepara-
tion will be needed.
43
When tlu'i-e is soft mud of some depth it is necessary that
the bottom be prepared in some way that will prevent the
ycung oysters fnmi settlino: into the mud enough to be in danj^er
of suffocation. This end is usually brought about by distribut-
ing over the surface of the proposed bed some material which,
resting on the mud, will form a surface on which the oysters
may be placed with safety. The materials most frequently used
are oyster shells, sand and gravel. When shells or gravei are
used they serve the double purpo.se of furnishing the necessary
support for the seed, and besides fiii-nisb a pku-c (.1" attach-
ment for fry at the breeding season.
Sometimes areas are found where the bottom is so soft thai
it is practically impossible to bring it into a condition where it
may be used with safety. The shells or other hardening agents
sink into the mud ver\' rapidly or become covered with new
layers of sediment soon after they are put down. However,
such are^s are of very rare occurrence and the surrounding
sections frequently furnish the best growing conditions to be
found anywhere.
SEED.
After the bottom has been prepared according to its re-
quirements, the next consideration is the actual planting of the
oysters. Seed oysters are young, or immature, oysters of suit-
able size for planting. They vary in size from young spat a
fraction of an inch in diameter, to well-grown oysters that will
be in a condition for market within six months from the time
when they are put on the bed. In most cases they are from
one to two inches in length. Except in some special cases where
the larger seed may be obtained cheaply and the same oysters
marketed at a profit Avithin a short time, it will be found that
the smaller seed at the time when it is planted the greater will
be the returns on the capital invested in the enterprise.
The seed is obtained from planters who make a specialty of
raising it or from tlie natural reefs. In this State th<> seed taken
from the natural reefs is restricted to the same size of oysters
that may be taken for the market. The immense beds of coon
oysters found in many sections of this State provide a prolific
source of seed. The oysters on these reefs are densely crowded
{'.nd never reach a ijood size or shape under tlie restrictions of
44
the natural conditions to which they are subjected. When oysters^
are taken from these reefs, and after having been separated, are
planted on a bed where they will have plenty of room and an
abundant food supply, they will be found to grow very rapidly,
while the shape and condition will improve immensely. In mak-
ing use of the coon oysters for seed it should be born in mind
that the larger and older of these oysters have reached a stage
in their development when they are less susceptible to the influ-
ence of changed conditions than are the younger ones. Conse-
quently the improvement in the older oysters will be very much
less, and will also take much slower, than in the younger ones
that have not become so permanently misshapen.
The care with which the seed is prepared, that it is cleaneJ
and sorted, is a prime factor in its value. If the seed is put
down just as it is taken from the natural reef a large portion
of it will consist of shells and other inert matter, which be-
sides having no value for a possible increase, will tend to intro-
duce on the new plant many of the enemies which will be detri-
mental to the growth of the young oysters. The uneulled seed
is very likely to grow into poorly shaped oysters so that the
returns from the plant will not be so great as if properly culled
seed had been used. While the uneulled seed can be obtained
for a much lower price, per bushel, the returns from the same
number of acres of plant at the time of marketing the crop
will be so much less, that the first cost will be an insignificant
consideration. To get the best results the seed should be of
pretty uniform size so that it will all mature at practically the
same time. In this manner the labor in handling at the time
the oysters are harvested will be reduced as much as possible.
The locality from which the seed is taken is also of im-
portance. Oysters taken from one locality to another, where
the conditions, especially the temperature and salinity of the
water, aro very different will not become acclimated for some
t\m«„ au\\ \u\ly after there has been a good deal of loss among
the seed. The young oysters are much more hardy and
stand the shocks of any change in their en\dronment better than
the older ones. If the larger oysters are transferred near the
time of the usual breeding season, it often happens that the
generative products degenerate so that no embryos are formed
at that season. ■ :
45
SO\VL\G I HE SEED.
The seed oysters nie scattered uver tlie beds by beiii^- tliruwii
from boats moored over the area to be planted. The greatest
eare should be used to get tliem as evenly distributed as possible
as only by this means can the best results be obtained. When
the seed oysters are deposited in heaps many of them are pre-
vented from getting a proper food supply, while the crowding
will cause in-egularities which will lessen their market value.
In r)rder to assure an equal distribution of the seed, the bed
may be n)arked oil' into areas of equal size and the same amount
of seed distributed over each of the subdivisions. Another
method is to anchor the boat over the bed and to scatter the
seed over an area which can be conveniently covered by throw-
ing the oysters from the boat with a shovel. The boat is then
moved to another station and the process repeated. The oysters
should not be deposited very thickly, five hundred (500) to
eight hundred (800) bushels to the acre being the amount that
seems to give the best results. There would of course be room
for a much larger amount of seed without danger of much
crowding while the oysters are young; but as they grow larger
the extra space will be taken up and the demand for food will
be greater. When the oysters are sown too thickly on a bed it
will be found that they will not grow nor fatten so rapidly,
besides the trouble from crowding.
WORKJXCr THE BEDS.
When seed oysters of good quality, that is pi-operly selected
and separated, have been used and the quantity used not too
large, it is not usually necessary to work the beds.
When the oysters are grown in the neighborhood of very
muddy bottoms, it is frequently advisable to tran.sfer them to
some other locality where the bottom is hard, so that the muddy
matter in the gills and mantle cavity of the oysters may be
washed out and the objectionable appearance and flavor cor-
rected before they are sent to the market.
In this connection reference may be made to the practice
of plumping or floatinsr. frequently called fattening by the
oyster men. which will be treated in another .section of thi?
report.
46
PLANTING WITH CLUTCH.
This method of oyster culture is the one which has been,
the longest in use in this country, and it offers the most en-
couragement for the future giowth of the oyster industry. The
method of planting seed oysters improves the quality of the
oysters available for market at any time, and, perhaps, utilizes
some which would otherwise never reach a salable condition:
but nevertheless many of the oysters used as seed would have
reached the marketable size if left on the natural reefs. Mor-
over, the natural reefs are being rapidly depleted by the drains
made on them by taking the adult oysters for market and the
young for seed.
As the number of the sexually mature oysters on the beds
are being reduced, and the remainder are becoming scattered,
the reproductive capacity of the beds is being lowered; while the
removal of the shells as well as the oysters leaves much less
chance of the spat becoming attached. Since the seed-produc-
ing powers of the natural reefs are beinsj reduced, the planter
must look elsewhere for his supply of seed or take up some
other method of culture which will release him from his depend-
ence on the natural increase. Both these ends, the lessening
of the drain on the natural reefs, and the independence of the
oyster planter, are brought about by use of the method of
planting clutch. Moreover, there is brought about an actual
increase in the number of oysters growing in any body of water
where this method of culture is practiced.
It has been known for a long time that not only natural
objects in the water near oyster reefs, but also any clean, hard
body which was dropped into the water in these regions at the
breeding season, would, after a short time, become covered witli
a dense growth of spat. Naturally this method of procedure
began to be practiced with the definite intention of catching
spat and thus increasing the amount of seed. From this begin-
ning the present system of planting clutch has been developed.
PREPARATION OF THE BOTTOM.
The bottom used for this method of culture must be firmer
than that which was required for the bedding of seed, and
there must not be anv danger of a deposition of sediment at the
47
time when the spat are becoming attached. If the bottom is
naturally very soft, it may be prepared by the application of
some hardening agent as was mentioned in the section on plant-
ing seed. On a moderately hard bottom, clutch may be applied
without any previous preparation.
One of the greatest difficulties in spat collecting is to avoid
the deposition of sediment on the clutch, as an amount of sedi-
ment, which would have no effect on an adult oyster, will h^
sufficient to destroy the spat. At the time of the attachment
of the spat it is about one-nineteenth of an inch in diameter, so
that a very slight deposit of sediment immediately before, or
after, its attachment would be sufficient to smother it.
On this account it will be seen that the soft bottoms which
present the best conditions for the growth of the oyster offer
special difficulties in the collection of the spat, while localities
where the conditions are the most favorable for the attach-
ment of the spat are the ones Avhere the later erowth of the
oyster will of necessity be slow.
CLUTCH. COLLECTORS, STOOL.
By these terms is understood any linn and cIhuu body
placed in the water to afford a chance of attachment for the
oyster fry at the time when it is ready to abandon its free-
swimming existence. A great many different materials have
been suggested and used for this purpose both in this country
and abroad. Some of the most important will now be discussed:
OYSTER SHELLS.
Oyster shells have been most generally used for clutch sine;-
the be-inning of this method of culture in this country. Tb.'
chief factor which has drtormined their use has probably been
the fact that they were available in almost all sections' where
oyster culture was taken up and could be obtained cheaper thaii
any other material that would serve the same purpose.
The shells ai-e usually scattered broadcast over the ground
which is to l)e planted in the same manner that was described
for preparing the bottom for plnnting with seed oysters. When
the bott(mi is snffifiontly firm to prevent the settlinir of the
48
shells it is customary to spread them as evenly as possible over
the bottom so that they will offer the greatest amount of surface
for the attachment of the spat. When the bottom is very soft
so that the shells would sink before the young oysters would
have become large enough to successfully overcome such condi-
tions, it is necessar^^ to make some special provision for harden-
ing the bottom. In such eases the shells may simply be planted
more thickly so that some of the upper ones will be kept above
the mud ; or, as is more satisfactory, the bottom may be surfaced
with a layer of shells some time before the actual planting of the
clutch, the latter being put down at the beginning of the breed-
ing season so that they will be in good condition nt the time
when the fry are abundant in the waters.
The quantity of shells to be planted per acre will depend
to a great extent on the character of the bottom in question, be-
ing, of course, greater where the bottom is at all soft. In any
case enough shells should be used to assure the complete cover-
ing of the bottom with a layer at least one shell deep. If evenly
distributed, 2,000 bushels of shells will give a layer one shell
in thickness over one acre and the amounts necessary to pre-
pare any bottom may be reckoned on this basis.
When single valves of the oyster shell are used for j)lant-
ing it will be found that they will fall with the concave side
of the shell uppermost, so that the edges of the shell on the
under side will remain clean for the longest time and the
largest number of spat will become attached to this part of
the shell, although all be of equal cleanliness. Since the oyster
fry seem to prefer the under side of the shells as a place of
attachment, it follows that by putting down a sufficient quan-
tity of shells to make a layer two or more shells in thickness,
there will be a mu'ch greater surface exposed on the under side
of the shells and the chances of a good set of spat thereby
increased.
OTHER FOE MS OF CLUTCH.
While oyster shells are the most frerriputlv used for clutch,
thei-e are several disadvantages in the use of this material which
may be overcome to a great extent by the use of some other
f('rm of cluteli. The ovster shells on account of their size afFord
49
a place of attaehmeiit for a large uimiber of spat, aud as soon
as the young oysters begin to grow there is a tendency to crowd-
ing. The ordinary oyster shell is so thick and strong that the
pressure developed among the growing oysters is not sufficient to
break up the shell to wliieh they may be attached, so that unless
the clusters are broken up by hand, or by the use of a dredge,
the oysters will become badly misshapen and their market value
much reduced. In a region where the supply of food is abun-
dant and other conditions favorable so that growth is very rapid,
this factor becomes of vital importance to the oyster culturist
While the use of any form of clutch that will lessen the chance
of producing misshapen oysters and at the same time lessen
the amount of work necessary on the beds will bring about a
great saving in time and labor.
CLAMS AND OTHER SHELLS.
Immense banks of the shells of a small, claui-like mollusc
{Gnathodon cuneatus) occur at many points in the oyster-pro-
ducing section of this State. These shells are about as large
as a quarter or half dollar, and on account of their small size
make an especially good form of clutch. In practice it is found
that only a comparatively small number of spat will become
attached to one of these shells, and by the time when the young
oysters have reached a size when there is danger of crowding
only one or two of them will have survived, so that oysters of
good shape will be produced without the necessity of taking up
and separating the young growth. In sections where these
shells occur in abundance it will perhaps be found best to use
the smaller shells to make a surface on the bed after the bottom
has been prepared by the use of oyster shells, especially when
the bottom is very soft.^ The larger shells will harden the bot-
tom more surely than the smaller ones, and besides would leave
the latter free from any chance of becoming mudded up.
In some of the Northern States the shells of the scallop
(Pecten), and some of the fragile snail shells, are used for
clutch in preference to the oyster shells. These shells are likely
to be broken up by the pressure developed by the growinnr
oysters, so that the question of culling is left to take care of
itself, and the oysters need no attention until they -.wo renrly
for the market.
50
Single oysters attached to small clam shell which makes a perfect collector
(reduced one-third).
From Bull. No. 3, Gulf Biol. Station, after J. L. Kellogg.
When the clutch is planted with the intention of securing
seed which is to be transplanted to some other bed to mature,
it is frequently desirable to use some form of chiteh which will
either break up easily or from which the young oysters may be
separated without any danger of their being injured during the
process. In some places the bottom is so soft that it cannot be
hardened by the application of any of the usual methods, but
where the conditions are such that a good set of spat would
be secured if there was any material present to which the spat
might become attached. In such eases many different forms
of clutch have been used with varying success.
51
BRUSH.
in the very soft places one of the most uniformly successful
methods has been to use small brush. The lower ends of the
branches are stuck in the bottom so that the greater part of the
twigs will be a foot or so above the surface of the mud and away
from any danger of being covered up. When the breeding
season is over the brush may be taken up and the young oysters
separated before they are put on the growing bed. Sometimes
this form of clutch is used for making a permanent bed; the
supposition being that by the time the brush disintegrates the
oysters will have become so large that there will be no danger
that they will settle into the bottom enough to become covered
up and stifled.
In some foreign countries, principally Japan, oysters are
grown attached to brush until they are ready for market; but
as they have to be sold before they have become very large, this
practice will probably never become general in this country.
GRAVEL AND PEBBLES.
In some sections the oyster men make use of coarse gravel
or small pebbles for clutch. This material has the same ad-
vantage as the small shells; only a comparatively small num-
ber of spat becoming attached to a single fragment. AVhen these
materials are to be used it is necessary that the bottom be
firmer than for the use of coarse material such as oyster shells.
The shape of the individual fragments, as well as their small
size, makes them very liable to receive a deposit of sediment
sufficient to prevent the settling of spat unless they are in a
region where the water is particularly iree from suspended mat-
ter of all sorts. On firm bottoms where there are currents of
sufficient strength to keep the pebbles clean until the oysters
have become attached, this form of clutch offers one of the best
means of securing a growth of oysters which will require verv
little attention until fully grown; or at least until there is
crowding from the presence of the young of a second year
which may have settled on those first attached to the clutch.
Many other materials have been used for catching spat,
but most of them cannot be secured in sufficient quantities to
bt of practical value in making plants of any extent. In regions
52
where there is a very heavy set of spat over a rostrieted area,
some of these materials, such as old tin cans or other scrap,
might be used to advantage. After the spat have been secured
and transferred to the growing bed ,the clutch would break up
and entirely disappear so that the oysters would be liberated
and allowed to grow up as good-shaped individuals. In muddy
places, this form of clutch would remain above the mud until
the oysters had reached a considerable size, so that they might
rest on the mud without danger of sinking and being smothered.
COATING CLUTCH.
In order to overcome the difficulty that has been mentioned
.in speaking of the larger forms of clutch; namely, the setting
of a dense growth of spat which will become densely crowded,
there has been proposed the method of coating the clutch with
some material which will break off under the pressure deveiopect
among the growing oysters or may be easily scraped oft' by the
use of some suitable instrument. This method would be ap-
plicable only when the young oysters are to be transplanted ta
a growing bed and the clutch recoated and used over again.
The materials wliieh have been used to coat the clutch have
been in most instances some mixture of sand and cement, in
M^hich the collectors are dipped and allowed to dry before they
are put in the water. The thin layer is easily separated after
the spat have grown to a size when it is safe to move them
to the permanent bed.
GENERAL CONSIDERATIONS ON SPAT COLLECTING.
Whatever may be the character of the clutch used, it is
essential that it be without any surface deposit which might
prevent the fixation of the spat. For this reason the clutch
should be placed on the bed as near the beginning of the
breeding season as practicable. In almost any body of water,
where the currents are not unusually strong, it will be found
that there is a constant deposition of sediment, so that the
longer the clutch is left down before the beginning of the breed-
ing season, the greater will be the chance that it will become
covered with a deposit of slime which will interfere with the
setting of the spat.
53
lu making a plant with clutch it is necessary to consider
tlie location of the area to be planted in relation to liin natural
oj planted beds in the same lociility. If there are any extensive
beds in the vicinity of the area selected it is probable that the
waier over the plant will teem with fry at the breeding season,
and an abundance of spat will be secured. When it is desir-
able to start a plant in a region where there are no beds of
oysters, it has been found that a comparatively small number
of breeding oysters placed on the bed before the beginning
of the breeding season will in most instances be sufficient to
furnish the fry necessary to secure a good set of spat. When
mature breeding oysters are to be placed on a plant to furnish
the fry for stocking the plant, it has been found that they
should be taken from a region where the conditions are as nearly
as possible the same as those in the place to which they are to be
transferred. They should also be transferred some time before
the beginning of the breeding season if good results are to be
obtained from the use of this method. AVhen the breeding oys-
ters are taken from a reef to a locality where the conditions of
salinity and temperature are very different, the sexual products
often degenerate and none will be given off at the time of the
first breeding season after the transfer.
If the bottom is firm, or has been prepared for the recep-
tion of the clutch by artificial hardening, it is best to put down
the breeding oysters some time before the clutch, so that the
oysters will have had time to become acclimated.
Usually from 30 to 60 bushels of good-sized oysters to the
acre are put on the bed to furnish the fry. In depositing the
breeding oysters the best results will be obtained if these are
put in bunches rather than scattered evenly over the bed. Since
the sexual products are thrown free in the water and can live
for a short time only unless fertilization takes place, it follows
that if the oysters are near together there is more chance that
the eggs and male elements will meet before their vitality is ex-
hausted. Once the eggs are fertilized, the swimming move-
ments of the larvae, and the currents in the water, will take
care of the distribution of the spat so that the set will be pretty
even over the whole area, provided there is an abundance of
the spat.
54
In most parts of the Louisiana oyster fields there is always
an abundance of spat so that years with no set, such as have
been of frequent occurrence in the North, are practically un-
known in this section. In most places the liability of the set
being too heavy is much more to be expected than that there
will be a scarcity of the spat.
WORKING THE BEDS.
Many of the oyster planters, especially if they have extens-
ive beds, are content to allow the oysters to remain without any
attention until the time when they are to be taken from the
bed for the market. In some regions where the growth is slow
and when collectors that would offer a place for the attachment
of a few spat only had been nsed, this neglect might not result
in any great amount of crowding and consequent lessening in
the value of the oysters; but in this state, where the growth
is very rapid, and the danger of crowding consequently great, a
plant made with clutch should be worked over each year if the
greatest returns from the investment are to be received. In
practically every section of the oyster fields there is, as has
been previously mentioned, a set of spat each year, and if the
beds are not worked over frequently the younger growth will
crowd the older ones so that within 4;wo or three years from the
time when the clutch was put down the plant will be in the
same condition as a natural reef that has never been worked.
The growth of oysters in this section is so rapid that within
one year from the time when the clutch has been put down,
many of the oysters will be large enough to be marketed with
profit. In Avorking over the beds it will be found that enough
cf the oysters may be saved for sale to cover the expenses of the
labor involved, while the improved condition of those left on
the bed will make the final returns much greater than would
have been the case if there had been no time given to working
the plant. Not only will the condition of all the oysters be im-
proved, but the actual number of bushels of oysters taken from
the bed will be increased.
It will usually be found that the young oysters present
on a plant when it is first worked are sufficient to stock an area
considerably larger than the original bed. When the surplus
55
has been removed to new bottoms the total area covered will often
increase the size of the plant by a third or more.
In the artificial cultivation of oysters, just as in the culti-
vation of any crop that grows on land, the greater amount of
work done on the plant the greater will be the return from the
crop; and there ought to be no more necessity of impressing
on the "oyster farmer" the importance of working his plant
than to tell the agriculturist that to assure a good yield of
cotton or cane it is necessary to do more than to plant the seed
and wait for the time of harvest.
The oyster industry in the waters about Long Island Sound
has been built up to its present proportions by the attention given
to the planted areas, and if a great and productive industry of
this kind is to be built up in the waters of this State, it is abso-
lutely essential that the oystermen be impressed with the neces-
sity of looking carefully after the well-being of their plants.
"When it is impossible to give the beds the attention they
should have, much may be accomplished by the simple practice
of drawing over the beds some heavy instrument like a dredge
or even a heavy iron harrow. Some of the oysters will, no doubt,
be killed by this method, but many of the others will be released
from the confinement of their crowded condition and will as-
sume their normal shape. The improved condition of the oysters
which are not injured in this process will more than compensate
for any loss that may take place at the time of the breaking
apart of the clusters.
FATTENING, PLUMPING.
The only method of fattening — so called — generally used in
this country is one that does not actually fatten the oysters, but
only gives them an appearance of plumpness which adds to
their value in the market. The oysters are taken from the
beds where they have been grown and transferred to some
place where the water is fresher. Here they become bloated to a
considerable extent through the interchange of fluids between
the oyster and the surrounding water. This adds nothing to
the oyster; but rather tends to extract some of the nutritive
materials from its body and to injure the flavor. Since the
demand is for the plumped oysters and their value is increased
59
thereby, it is worth while to carry out this system for the
financial consideration. In practice the plumping may be ac-
complished at the time when the oysters are taken from the
growing beds and rebedded to become cleaned from the mud
within the shells.
A true fattening process, that is an increasing of the fat-
ness of the oysters by supplying an abundance of food material^
has been long practiced in Europe where the most of the cul-
ture takes place in enclosed ponds. In this country sucm a
method has been considered too expensive to be justified in
general practice. During the last few years, however, experi-
ments have been carried on by the United States Bureau of
Fisheries at Lynnhaven, Va., to discover some method of fatten-
ing oysters which could be practiced on a commercial scale un-
der the restrictions imposed by the comparatively low price
of oysters in this country. In these experiments the amount of
food in the fattening ponds has been increased by the applica-
tion of ordinary commercial fertilizeres some time before the
beginning of the oyster season, so that there would be an aiaan-
dance of the diatoms before the first oysters were put in the
ponds. The water in the ponds was confined so that none of
the food material could escape, while the currents, to cause the
necessary distribution of the food^ were maintained by the use
of a "screw propeller" installed in one of the narrow canals
between the ponds. The oysters were put in cages suspended
in the ponds and allowed to remain some time. The improve-
ment in the oysters fattened by this method, was so great that
they commanded a much higher price in the markets of New
York and Philadelphia than those taken from the reefs or beds
and sold without having undergone the fattening proce^js. There
are as yet certain difficulties to be overcome in the matter of
controlling the character of the organisms which will de\Tlop
under the artificial conditions, as well as in the mechani'^al con-
struction and arrangement of the systems of ponds. So that np
to the present time the system has not been developed to a
point where its commercial possibilities are assured.
'/.H^';
