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Continuation of Experiment in Propagating Eastern
Oysters on the Oregon Coast: Report
of work, Summer of 1808.

F. L. WASHBURN A. M.

University of Oregon, Eugene, Oregon.

The following is a brief synopsis of the work done last summer and is a con-
densation of the more technical report mailed to the U. S. Fish Commission at
Washington.

The introduced oysters were found in July to be in excellent condition and
spawning. The process of artificial fertilization was agan resorted to, and countless
thousands of fertilized eggs and swimming embryos were consigned to the waters
of the bay. This process has been fully described; its value lies in the fact that im-
pregnation is assured if eggs are fertilized in the laboratory, and if they are nursed
through the early stagesthere is that much less exposure to conditions occasionally
prevailing in the waters of the bay which are unfavorable to their survival. In this
connection acknowledgements are due Dr. W. K. Brooks, of Baltimore, whose reports
on similiar work have been extremely helpful. This year, convinced that the
warmer and less salt water farther up the bay was more suited to the developing
spawn, it was for the most part deposited between Oyster City and the so-called
‘Ship Yard’’ 2% miles above the present plant. Some spawn was carried above
this point. Further, in the vicinity of the Ship Yard we placed in deep water in

Isig4y .

three places a small number of spawning oysters, and later about 200 oysters from
the government plant were placed on a breeding float and said float anchored near
the Ship Yard. While this float was anchored near Oyster City before being towed
to the Ship Yard a very interesting and encouraging thing happened; viz: the water
in the float reached a temperature of 70° F. and the oysters spawned rendering the
water milk white. The oystermen, many of whom are skeptical as regards artificial
fertilization, were summoned that they might witness the spontaneous spawning.

The Ship Yard is about nine miles from the ocean and marks the upper limit
of the tonging grounds for our Yaquina Bay Oyster (Ostrea lwrida.) Small speci-
mens of this oyster are found somewhat farther up the stream but they are periodi-
cally killed by winter freshets. In this connection it may be mentioned that the
eastern oyster can endure much fresher water than our west coast species; in fact it
s constantly in such water on its native beds.

Observationson salinity and temperature, surface and bottom at different tides
both at Yaquina and Coos Bay corroborate the results of last year’s investigations in
this direction. It must be confessed that the waters of our bays are occasionally
subject to sudden changes of temperature and salinity on different tides which must
effect unfavorably the spawn of the introduced oyster, but I do not think this neces-
sarily means the failure of the experiment, since, if the spawn should start to de-
velop in a favorable period, it may have passed beyond its tender, critical stage
before meeting the fatal conditions alluded to. It should be borne in mind that, in
the case of any species of oyster, not every season offers favorable conditions for
spawning. Oncein every few years, however, it may happen that different natural
forces combine favorably and the result isagreat abundance of spat (i.e. spawn
which has developed and become fixed,)

There seems tu be considerable misconception regarding the condition
of the eastern oysters which have forso many years been shipped from the
eastern coast to San Francisco Bay. Many think that they do not spawn there
while some do not hesitate to declare that their progeny is most abundant, so much
so as to materially affect shipments in recent years. Asa matter of fact, the intro-
duced oyster does spawn there and the spawn develops; a considerable number of
eastern oysters, spawned and developed there, being frequently found; but Lam led
to believe, from what I hear from an authority ina position to obtain accurate in-
formation regarding the shipments of the bivalves, that the production has not
been great enough to materially affect importations from the east.

It might be mentioned incidentally, tho’ it has no bearing on the eastern oyster
question, that large shell heaps of our west coast oyster found on the shores of Coos
Bay give proof that many years ago this oyster which now flourishes at Yaquina,
Netarts, Shoalwater Bay and elsewhere lived and flourished there until annihilated
by some sudden catastrophe, possibly an unusually destructive freshet bringing into
the bay a large amount of mud.

The oyster industry at Yaquina Bay is not what it used to be, and I have on
several occasions pointed out to the oystermen there that the number of native oys-
ters on their planted beds might be increased by the use of brush collectors, to catch
any drifting spawn, which, lacking something to catch on, settles on another’s bed
or on public ground. They are not disposed, however, to adopt new methods and
content themselves with the old and good, but insufficient method of strewing
clean shells on the beds.

Future Prospects of the Experiment.

In commenting upon the attempt to introduce the eastern oyster, the press of

the state has run the gamut from declaring it an absolute failure to promising our
citizens an abundance of this delicious bivalve grown in Oregon within a year or
two. The wiser course to pursue, regarding the effort as purely an experiment, is to
avoid the Scylla of pessimism and the Charybdis of extravagant hopes. The out-
come of the experiment can not be even partially decided for two years from now.
No eastern spat from the spawning of a year ago, was found thissummer. It is too
soon to observe results of this year’s spawning. Iam so confident that we shall
eventually discover spat of the eastern oyster that I have this fall offered a prize to
the individual who first sends me living spat of Ostrea Virginica foundin Yaquina
Bay. The spawning of the oysters on the float when taken from the government
plant has already been alluded to as an encouraging sign. Iwas more particularly
impressed by the following. Inthe laboratory experiments in artificial fertiliza-
tion one set of eggs was startedin water from the bay which registered 1.022,
almost ocean saltness. Two days later microscopic investigation revealed numer-
ous swimmingembryos. The water was exposed during that time to the varying
temperature of the laboratory, from 59° F. to 70° F. This speaks well for the hardi-
iness of the young spawn and for possibilities on the planted beds at Oyster City.

The oysters were in far better condition this season than during their first sum-
mer here, showing that they are becoming acclimated. It may not be generally
known that two varieties of the eastern oyster were sent us in 1896,—a somewhat
elongated variety from East River, New York, and a round variety from Long
Island Sound, called Princess Bay. The latter coming from a locality nearer the
sea has done better than the East Rivers. Unfortunately only a small proportion
of the twenty-two barrels was represented by this variety. We have grounds for
hope thatthe Fish Commission will send us more Princess Bay oysters this season.

If money were available to make salt ponds where the proper conditions as re-
gards temperature and saltness could be maintained, eastern spat could be raised
artificially in very large numbers. Assuming that this is not feasible, the experi-
ment resolves itself into a question of Natural Selection. That is, some spawn, as
time goes on will undoubtedly, inheriting the acquired hardiness of their parents,
pass successfully through the tender and critical period and become attached as
spat to rocks, shells, etc., in Yaquina Bay. Their progeny, parent and offspring
having become acclimated, as it were, will be more likely to developin large num-
bers than their ancestors, so that, eventually the bay will be more or less stocked
with the bivalves. To what extent and how long it will take is, of course, a matter
of conjecture. Judging from the conditions prevailing in San Fransisco Bay, where
oysters have been planted for years, it would be the safest plan not to expect too
much from our experiment. Asa cause of encouragement, however, we have the
fact that at San Francisco they have made no such efforts toward this end as we
have here. The experiment is well worth the very small sum it has cost the gov-
ernment; it has cost the state nothing.

The upper row of oyster shells, in the photograph which heads this report,
have lost, in transportation and in handling, about %-inch or more of delicate
growth not yet hardened, marking their increase during the latter part of this
season.

These oyster, like all the fish interests of the state are under protection of the
State Fish Commissioner who will see that a special bill for their protection is pre-
sented at the coming session of the legislature. It is the intention ofthe U.S. Fish
Commissioner that the present plant be always preserved as a spawning plant, and

that, after a stated time, the progeny of the introduced specimens, if there be any,
may be lawfully marketed.

My thanks are due to Mr. George King, of Oyster City, for much volunteer
labor and assistance in the experiment.

What is an Oyster?

The old conundrum and its answer, ‘‘Why is an oyster
like an elephant? Because neither can climb a tree,”
does not, strangely enough, convey a sufficiently clear
idea of the oyster’s anatomy and life history to satisfy
the mind of the average citizen, and I have been asked
by friends to tell what oysters are and something about
their habits.

TENE it

The ae sub-kingdom known as Mollusca contains the snails, clams, oys- .
ters, devil fish, &c.,—animals which have very soft bodies which may or may not
be protected by ashell. Inthissub-kingdom occur several classes, one of which the
Lamellibranchiata, (i. e. Mollusca furnished with plate-like gills) includes the
clams and oysters, in other words, all the bivalves. The oyster family, Ostreidae,

belonging to this class contains all the oysters in whatever part of the world they
may live; the small ovster of our northwest coast, the so-called eastern oyster, the
European oyster, the pearl oyster, etc. All possess certain characteristics in com-
mon which place them in the same family. Furthermore, the genus Ostrea, one
division of the family, includes more than 70 species, of which our west coast oys-
ter, Ostrea lurida and the eastern oyster, Ostrea Virginica
are the two forms we are most interestedin. Lastly, the
eastern oyster takes different shapes and reaches different
sizes in different localities and receives different colloquial f
names, East Rivers, Princess Bays, Baltimores, Blue Points, ¥
&c., but these are all the same species whether they are
found in the deep cold water of the Gulf of St. Lawrence or
in the warmer waters of the Gulf of Mexico. All oysters eae
love a bottom of shell and mud, or gravelly mud, not too soft, for in such they
would become smothered. In the spawning season the optimum temperature for
the eastern oyster is between 70° and 80° F., and they are accustomed as a rule to
much fresher water than is our west coast oyster.

The eggs of the eastern oyster when first laid are irregular in shape and each
egg is about 1-500 of an inch in its longest diameter. (See Fig. 1.) ‘These eggs are
ejected into the water while our oyster (Ostrea lurida) retains its eggs inside of

ts shell until the embryos are far along in their development. As if to compensate
for the lack of protection in the former species, a very care-
ful estimate places the number of eggs laid at one spawn-
ing by a single eastern oyster at 60,000,000 (only a very
small portion of them survives) while our small oyster lays
only between one and two millions. If the egg of the east-
#3 ern oyster floating in the water, does not shortly meet a
J sperm cellit quickly dies. About two hours after being fertil-
ized it becomes round (Fig. 2) and shortly begins to seg-
ment, forming 2, then 4, then 8, then 16 cells and so on.

At an early stage of segmentation it looks something like Fig. 3, the two polar
globules being still seen attached to the egg. Fig. 4 shows the
result of this rapid cell division, and Fig. 5 a little later period
than that shown in Fig. 4.—27 hours
after impregnation and just previous
, tothe swimming stage shown in Fig. 6.
At this period, thirty hours after fer_
tilization, the embryo moves rapidly
through the water by means of the cilia

Fig. 4.
Fig. 5. or hair-like growths shownin the figure, All See stages
can be readily seen under the microscope and were observed repeatedly by the
writer in his seaside laboratory. Figure 7 shows an oys-
ter embryo at a considerably laterdate. 2to4 days after &
fertilization, with its delicate transparent shell showing, §
the alimentary canal and the mouth. When the oyster &
embryos are at the stage shown in Fig. 6, they crowd to B®
the surface in large numbers. It is at thistime that they
are explosed to the greatest dangers, to the danger of
being eaten by small fish, danger from change of air
temperature, &c. Hence the value of artificial fertiliza-

tion and subsequent care in ihelabomstary: in
which process they need not be consigned to

—the outside waters until they have passed the
critical period alluded to. It is important,
therefore, that this process should be resorted
to every season until the introduced species
has obtained a foothold.

Later, when they have acquired their deli-
cate shells, they sink to various depths and are
he less liable to fatalities. It is not, however,

Fig. oa until they have swum about for from 6 to 8
days that they settle on a piece of clean shell, or piece of crockery, a brick, old
shoe or rubber, clean wood or rock, anything in fact that is not slimy and there
become fastened as spat (Fig. 8.) never to move from that place of their own ac-
cord. The spat of the eastern oyster when first formed is about
1-80 inch in diameter. They are hardly marketable before they
are four years old and may under favorable conditions live for 20
years or more. The spat are very apt to form in clusters on other
shells. Tonging brings these clusters to the surface and the oys-
ters are separated, the larger specimens are marketed, the smaller

Fig. 8. :
individuals being placed upon private beds to attain greater size. Hence we seein
markets and in restaurants single oysters and not clusters, nor are we apt to see the
original object to which each oyster was first attached as a spat.

Biological Laboratory, Nov. 20, 1898

UNIMON

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