Notes on the spawning habits of the razor clam

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NOTES ON THE SPAWNING HABITS

OF THE

RAZOR CLAM.

Machera patula — Dixon.
Siliqua (patula var.) Nuttallii—CoNRAD.

RECOMMENDATIONS -

REGARDING

PROTECTIVE MEASURES.

BIOLOGICAL LABORATORY, )
UNIVERSITY OF OREGON, >
SmEuGENE, April 5, 1900. §
His Excéllency, T. T. Geer:

Dear Srr:—This clam, which forms such an important
article of diet on this northwest coast, needs no introduction
to the people of Oregon. The genus is of wide distribution,
being reported as occurring in India, China, Ochotsk, Sitka,
Behring’s Sea, Newfoundland.

It is feared here, that, as a result of its unlimited persecu-
tion, both in summer and winter, it may eventually become
rare, or even extinct. To guard against any possibility of
the loss of this article of food, Mr. Johann Young, in the
legislative assembly of 1898-1899, introduced House Bill No.
118, to provide for its protection. The bill reads as follows :

A BILL
Foran Act providing for the protection of razor clams, and declaring an emergency.

Be it enacted by the Legislative Assembly of the State of Oregon:

Section 1. It shall be ualawful from and after the passage of this Act to
dig, take, kill, injure, destroy, buy, sell, or offer for sale any shellfish com-
monly known as the razor clam, between the first day of June and the

2 REPORT OF STATE BIOLOGIST.

fifteenth day of July, and the fifteenth day of October and the fifteenth day
of December of each year; provided, however, that it shall not be considered
unlawful for any person to dig razor clams for his or her own use.

Section 2. If any person shall dig any shellfish, commonly known as
razor clams, whose length is less than two and one half inches, they shall
immediately replace said clam in the place from which it was dug, with the
least possible injury to the clam.

Section 3. Any person violating the provisions of this act shall be pun-
ished by a fine of not less than twenty ($20) nor more than one “hundred
($100) dollars, or imprisonment in the county jail for a period of not less
than ten (10) days nor more than fifty (50) days.

Inasmuch as there is urgent necessity for the protection to shellfish this
act is intended to afford, it shall be in effect from and after its approval by
the Governor.

This bill passed the house and was reported favorably in
the senate by the Committee on Fishing Industries, but no
further action was taken, and the bill, in consequence, failed
to become a law.

In January, 1899, the Astoria Progressive Commercial
Association, through Mr. H. G. Van Dusen, asked me if I
would make an examination of clams, sent me from time to
time, to determine the season of spawning. . This I gladly
agreed to do, and batches of from six to ten were sent me
monthly from Astoria. These were given a careful micro-
scopical examination and the results reported to Mr. Van
Dusen. Before stating these results it will be well, that they
may be the more readily understood, to give a brief and pop-
ular description of the

ANATOMY AND HABITS OF THE RAZOR CLAM.
The name ‘‘Razor Clam,’’ by the way, is doubtless applied
to it on account of its elongated and somewhat flattened shape.
There are other species, however, in the same family, which
are more razor-like in appearance than the one we are so
familiar with as an article of diet.

The shell of a large individual will measure about six and
one-half inches, and, as every clam digger knows, they range
from that size down, the average being, perhaps, five and one-
half inches.

From the anterior end (the end that is down when the clam
is in the sand) protrudes the muscular ‘‘foot,’’ the tissues of
which are capable of being distended to some extent with water,
and the whole foot protruded several inches beyond edge of
shell and drawn quickly and forcibly back. This so-called
foot is really a part of the visceral mass or body of the clam

THE RAZOR CLAM Machera patula.

REPORT OF STATE BIOLOGIST. 3

which contains the alimentary canal, liver, generative pro-
ducts, etc. It is by means of this ‘‘foot’’ that the clam is
enabled to get out of the reach of the clam digger, if the latter
does not work quickly, for it stretches it down through the soft
yielding sand as far as it will go, then the lower end is ex-
panded, forming a temporary suction, and the retractor mus-
cles of the foot are then contracted. Ordinarily, the effect of
this would be to draw back the foot, but, the lower end of
this organ being at this time expanded or curved, the body of
the clam is drawn down to the improvised anchor, and the
process is then repeated. This, with minor modifications, is
the method of locomotion with most of the clams.

At the end of the clam opposite the foot the ‘‘siphon,’’
wrongly called the ‘‘ neck,’’ protrudes. This is a curious
organ and has to do with the respiration and feeding of the
creature. Two tubes traverse this siphon longitudinally, one
opening into the space just above the gills, the other, the one
nearer the ventral or free edge of the shell, opening into the
general space between the valves of the shell. In this space,
on each side of the visceral mass are two gills, four in all,
which serve as organs of respiration; and covering and pro-
tecting both visceral mass and gills is a thin layer of tissue
known as the ‘‘mantle.’’ This mantle lies next the nacreous
inner layer of the shell which it has helped to form by its
secretions. When the clam is inthe sand and covered with
water the siphon is stretched until its end is above the surface
of the sand. Water is drawn in the lower opening and passes
over and through the gills, the minute particles of food con-
tained therein being carried to the mouth which is at the
lower or anterior part of the animal; the water which has
passed through the gills, flows back and out through the other
tube, the exhalent tube of the siphon. The smooth epidermis
covering the outer surface of the shell is of a brownish color
and glistens as though it were varnished. There are evidently
nerve endings at the distal end of the siphon which are sensi-
tive to light and shadow, though this has not been definitely
proven for this species. The sexes are distinct, as will be
shown later. This is placed beyond all question, even if it
had not been previously known, by these recent studies. Yet
there are those in the State who claim that these animals are
hermaphroditic. Familiarity with the use of the microscope
and a knowledge of the anatomy of the creature would soon
dispel this erroneous conception.

4 REPORT OF STATE BIOLOGIST

METHODS OF EXAMINATION AND RESULTS.

In making the following examinations one valve of the clam
was removed, the visceral mass opened above the ‘‘foot,’’ and
some of the contents, after being spread on a glass slide, were
examined under high and low powers of the microscope.
When spawning, the ripe eggs, readily recognized with low
power, look like Figure 1.

ak ee the high power, the actively moving sperm resemble
igure 2.

RESULTS OF MICROSCOPICAL EXAMINATION.

Jan. 15, 1899.—No eggs nor sperm.
Feb. 27, 1899.—A very few immature eggs No ripe sexual products.
Mar. —. 1899.—Omitted examination. But note that the February examination was
very late.
Apr. 17, 1899.—Eight clams examined.
No. 1, ripe sperm.
No. 2, ripe sperm.
No. 3, many mature eggs.
No. 4, many mature eggs.
No. 5, many mature eggs.
No. 6, ripe sperm.
No.7, ripe sperm.
No. 8, spoiled.
1s99.—Ten clams examined.
No. 1, full of ripe eggs.
No. 2, full of ripe eggs.
No. 3, fall of ripe eggs.

o. 5, full of ripe eggs.
No. 7, full of ripe eggs.
No. 4, full of ripe sperm.
No. 6, full of ripe sperm.
No. 8, full of ripe sperm.

May 1:

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REPORT OF STATE BIOLOGIST. a)

No. 9, full of ripe sperm.
No. 10, full of ripe sperm.
June 22, 1899. =aele ‘clams examined.

No. 2, female which had spawned.
No. 3, female which had spawned.
No. 4, female which had spawned.
No. 5, female which had spawned.
No. 8, female which had spawned.
No. 1, male which had spawned.
No. 6, male which had spawned.
No.7, male which had spawned.

I use the term ‘‘spawned’’ for both sexes. The specimens
were all lank, had discharged their genitive products. Would
be called ‘‘poor’’ by fishermen.

The July examination was omitted because of press of work
connected with oyster investigations.

Aug. 23, 1899.—Ten clams examined.
No. 1, male with sperm.
No. et male with sperm.
No. 5, male with sperm.
No. 7, male with sperm.
No. 8. male with sperm.
No. 2, female with a few ripe eggs.
No. 4, female with a few ripe eggs.
No. 6, female with a few ripe eggs.

No. 10, female with a few ripe eggs
No. 9, no results.

These specimens all looked ‘‘lank”’ or poor, and the scarcity
of eggs would make it appear that the spawning season was
practically over.

Sept. —, 1899.—Batch of clams examined. Very few with eggs or sperm.
Oct. 13, 1899.—Out of a batch received on this date, very few were found with eggs: evi-

dently way past spawning.
Novy. and Dec. 1899.—No results.

From the results of the above examinations it is very evi-
dent that the bulk of the spawning is during April and May,
for it was during that time that I found them full of genera-
tive products. June examination showed that they had
finished spawning. A few eggs were found in August, it is
true, but so few as to indicate that the spawning season was
long over. In no case were ova and sperm found in the same
individual; in other words, the sexes are distinct. The de-
velopment of this species has never been studied. While it
is not of interest economically, it is of sufficient scientific im-
portance to invite investigation on the part of a biologist.

DEDUCTIONS AS TO PROTECTIVE MEASURES.

It is evident from the above that should the razor clam
need legal protection, the close season should be during April
and May, or possibly from March 15 to June 15, thereby
giving them every advantage of variation in seasons.

6 REPORT OF STATE BIOLOGIST.

A clam cannery, in its zeal to make a big season’s pack of
minced clams, might use very small individuals, such as one
seeking clams for his own need would discard. This contin-
gency is provided for in Mr. Young’s bill.

As I understand, it is not intended to prevent seashore vis-
itors from using clams during the summer months. This, in
view of the long stretches of beach where clam digging is.
indulged in, would be a matter of extreme difficulty, if not
an impossibility.

If this treatise throws any light on the best time for a close
season, supposing such protection were necessary, I shall feel
amply repaid for the expenditure of time and trouble it has
caused. My thanks are due Mr. Van Dusen for very kind
cooperation.

Respectfully,
Fr. L. WASHBURN,
State Biologist.

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