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Transcriber's note:

Italics is represented with underscore _, bold with the equal sign =
and small caps with ALL CAPS. Everything (including inconsistent
hyphenation and spelling) has been retained as printed, unless stated
below:

p. 7: "in the Misippi River" Misippi changed to Mississippi.

Some words were broken up due to line endings. As they only occur once
in the book it's not absolutely clear if they should be hyphenated or
not. This concerns the words: short-sightedness, sand-shell,
head-waters.




      DEPARTMENT OF COMMERCE
      BUREAU OF FISHERIES

      HUGH M. SMITH, Commissioner

      THE PROTECTION OF FRESH-WATER
      MUSSELS

      =By R. E.COKER, Ph. D.=

      _Director U. S. Biological Station
      Fairport, Iowa_

      Bureau of Fisheries Document No. 793

      WASHINGTON
      GOVERNMENT PRINTING OFFICE
      1914




      THE PROTECTION OF FRESH-WATER MUSSELS

      =By R. E. COKER, Ph. D.=

      _Director U. S. Biological Station, Fairport, Iowa_

      Bureau of Fisheries Document No. 793




      CONTENTS.


                                                                  Page
 Present conditions                                                  3
   The mussel industry                                               3
   Depletion of the resources                                        4
   The interests of the community                                    5
   Artificial propagation of mussels by the Government               7
     Establishment of propagation                                    7
     Results dependent upon protection                               8
 Protection                                                          9
   Essential considerations for effective legislation                9
   Examination of protective measures                               10
     Two measures for immediate application                         10
     Measures not suited to existing conditions                     10
   Size limit--necessity and application                            12
     Exhaustive nature of the fishery                               12
     Waste illustrated                                              13
     Size limit in relation to economy                              15
     Reasons for the proposed 2-inch limit                          16
     Details essential to effective legislation                     17
   Closed regions--necessity and application                        18
     Injury to spawning mussels and to young                        18
     Considerations determining size of closed regions              19
     Practicable division of river systems illustrated              20
     Procedure for establishing closed regions                      21
   Enforcement of the law                                           22
 Summary of recommended legislation                                 23




      THE PROTECTION OF FRESH-WATER MUSSELS.


      By R. E. COKER, Ph. D.,

      _Director United States Biological Station, Fairport, Iowa._




      PRESENT CONDITIONS.


      THE MUSSEL INDUSTRY.

The history of the fresh-water mussel industry gives illustration of
the promptness with which an American industry may be developed once
the pathway is found. Undertaken in a small way scarcely more than a
score of years ago, the manufacture of pearl buttons began almost
immediately to assume the proportions of an important national
industry. As early as 1898, when the enterprise was only 6 years old,
there were about 50 factories in more than a dozen towns along the
Mississippi. With improved machinery and methods further expansion
occurred, until within a few years the output approximated 30 million
gross of buttons, with a value of many millions of dollars. The growth
of the industry has continued to the present time, but exact figures
will not be available until the Bureau has completed a statistical
survey now in progress.

Not less important has been a resultant economic change, or
modification of custom, that has affected practically every person in
the country. Where marine pearl was in rare use, fresh-water pearl,
with its quality and price, came to fill a universal requirement. In
one decade pearl buttons were high in price, used only upon the better
clothing, and commonly saved when clothing was discarded, while in the
most general use were buttons of metal or agate or wood, which rusted
or broke or warped. In the next decade good pearl buttons, neat and
durable, were available to everybody and used upon the widest variety
of clothing. A former luxury had become a common necessity.

Coincident with the rise of the manufacturing industry, there developed
an important and widespread fishery, directly employing thousands of
persons and indirectly affecting persons and communities of varied
occupation. Commencing on the Mississippi River, the fishery gradually
spread from stream to stream, passing from depleted territory to new
and rich fields, until it embraced practically the entire Mississippi
Basin and a portion of the Great Lakes drainage, from Minnesota to
Louisiana, north and south, and from Ohio, West Virginia, and Tennessee
on the east to Arkansas, Kansas, and South Dakota on the west.


      DEPLETION OF THE RESOURCES.

Extension of territory could not be continued indefinitely. While up to
the present time the industry has not failed to obtain shells in
quantity sufficient for the market demands, it has become perfectly
clear that the perpetuation of the industry as one producing a staple
product that is both good and within reach of all people depends upon
successful propagation and effective protection. The supply is now
maintained by regularly invading new territory (and it is scarcely
possible to go farther in this direction), by seeking out the smaller
tributaries of the mussel streams, which could not formerly have been
worked with profit, and in some measure by the devising of methods that
are more effective in capture of mussels. Notwithstanding these
developments, all of which indeed conduce to more exhaustive fishery,
an increasing proportion of very small shells is being taken, the
bottoms are being more thoroughly cleaned, and the price of shell has
advanced to a relatively high figure.

A high price for shell has, of course, its advantages. It is good for
the fishermen, provided they can find the shells, and it stimulates the
manufacturers to eliminate waste and to use the most economical
methods. On the other hand, if unbalanced by protective restrictions, a
continued rise in price is of disastrous consequence. It impoverishes
the beds by driving the fishermen to the most exhaustive manner of
fishing; even the very smallest shells that can be captured, which
should never be removed from the beds, are taken and marketed, and
this, unfortunately, is the actual case at the present time. (See pl.
I.) Ultimately the higher price of shell becomes an element in the
price of the finished product and is paid by the public at large
without corresponding advantage to a single person connected with the
industry.

Let it be repeated that a high price to the fishermen is desirable, but
in the present condition they reap no benefit. A higher price for a
disproportionately smaller product brings no added profit. None are so
directly interested in the conservation of mussels as the fishermen
themselves.

Of what advantage is it to the fishermen of the Wabash River, or to the
State of Indiana, that shells are now more valuable, when a river that
once supported a really important shelling industry is now practically
depleted? Wherein is the benefit to Illinois, when only one fisherman
can engage in shelling to-day where six worked with profit five years
ago? What profit will Arkansas find, when its rivers are now the scene
of the most exhaustive mussel fishery ever known and the future is
being robbed by the removal of infant shells that are shipped to the
markets to be subsequently thrown into the discard by the manufacturers
as too small for any useful purpose?


      THE INTERESTS OF THE COMMUNITY.

An earlier general interest in the subject would have been awakened had
there been a better knowledge of the importance of shelling industries
to the communities at large. As an illustration, the case of Madison,
Ark., may be mentioned. The town itself has a population of about 300
and is supported by lumbering, farming, and fishing industries. During
each of the past two years shells and pearls have been marketed at this
place to the value of about $20,000. This was a crop that could be
counted upon regardless of weather conditions during the season, and it
constituted a substantial element in the income of the community at
large. Can this income be counted upon in the future? A dozen years ago
fishermen made their wages when shells brought $4 per ton, and they can
do no better at this time, when they receive $23 per ton. In 1913 they
took 200 to 300 pounds per day, where originally they made daily hauls
of 1,000 to 1,800 pounds. The shells are now, it appears, about
one-sixth as abundant as they were a dozen years ago. This is a rapid
rate of depletion, and it is evident that the future can have little to
offer unless something is done to insure the self-perpetuation of the
mussel beds.

The town of Black Rock, Ark., which has a population of about 1,000,
offers an illustration where both fishing and manufacture are involved.
It is estimated that approximately $50,000 is brought into the town and
the territory about it each year, of which by far the greater amount is
paid out in the town of Black Rock itself. What does the future hold
for this place? Reliable information shows that while a few years ago a
sheller could take 1,200 pounds or more per day from the Black River at
Black Rock, the daily catches now run from 100 to 200 pounds. Although
shells are bringing about $20 per ton, there is scarcely a daily wage
to be made, and as a consequence the shell fishery immediately about
Black Rock is almost negligible. The shelling is now prosecuted
principally above Black Rock, in the upper waters and tributaries of
the Black River, as about Pocahontas and elsewhere. The process of
depletion is unchecked and the condition is clearly such as to awaken
the enlightened sentiment of the community and the State at large to
support measures that will insure permanent life and prosperity to the
industry. Here is a business that yields a relatively fixed return in
comparison with agricultural industries, which are so generally
affected, favorably or unfavorably, by the vicissitudes of weather
conditions.

It is of much more immediate concern to the community at large than it
is to the purchasers of shells or to the shellers themselves that the
resources of a particular region should be conserved. It is a
comparatively simple matter for the manufacturer to strip his plant and
to remove his machinery to another locality with undepleted resources;
it is an easy thing for the sheller, with his scant equipment in a
house boat, to float down the river, looking to find another temporary
home where his labors may be more profitable. It is the interest of the
community that is threatened. The loss of a substantial industry
affects the profits and the welfare of innumerable persons who may have
known little of their indirect interest in a business in which they did
not immediately participate. The communities most immediately affected
are those of the river towns which, as a general rule, are too limited
in their sources of fixed income.

From the standpoint of community economy, an unfortunate feature of the
mussel fishery, as it has been pursued up to this time, has been its
nomadic character. The policy everywhere has been to clean up the beds
of a locality, or of a stream as a whole, and then to move to new
regions. Temporary cutting plants, or "factories," have frequently been
established in the vicinity of active shelling, to move subsequently as
the local fishery passed away. Only the larger and more firmly
established branch plants of the principal factories have maintained a
fixed location.

It will be brought out later in this report that it does not appear
possible to insure the best condition of the mussel beds, except by
some plan of rotation; but it would be desirable and favorable to the
interest of all for the mussel fishery to be a permanent and dependable
feature of the industrial life of the broader communities, if not of
particular restricted localities.

The perpetuation of the mussel resources may well receive the best
consideration of every State concerned and of the National Government
as well. It affects the welfare of thousands of shellers, of hundreds
of river towns over the broad Mississippi-Missouri Basin, of
manufacturers and laborers, east and west, and, it might be said, of
every user of pearl buttons, which comprises practically the entire
population of the country.

The Government and the States can accomplish the desired object by two
principal means--artificial propagation and legislative protection. It
is the province of the present paper to deal primarily with the
subject of protective measures, but it will be advisable to give first
an abbreviated account of the conditions and possibilities of
artificial propagation, especially as the results of propagation will
be greater or less according to the degree of protection extended to
the young mussels.




      ARTIFICIAL PROPAGATION OF MUSSELS BY THE GOVERNMENT


      ESTABLISHMENT OF PROPAGATION.

The Bureau of Fisheries has always maintained an active interest in the
development of the fresh-water mussel fishery of America, which, in its
importance and breadth of territory, is entirely unique in the world.
As early as 1897 and 1898, the shell fishery being then only 4 or 5
years old, the Fish Commission undertook investigations relating to the
various phases of the industry, and several reports were published
dealing with the natural history of mussels, the shell and pearl
fisheries, and the button industry. In a general report on the subject
Dr. Hugh M. Smith then recommended measures for the protection of
mussels. No action followed, and in consequence the scene of the most
important fisheries has greatly shifted since that time.

Some years later there began a special investigation of the
reproduction of mussels, which resulted in the methods of artificial
propagation as developed by Prof. Lefevre and Prof. Curtis, of the
University of Missouri, in association with the Bureau. The Government
then established the Fairport Biological Station to engage in the
propagation of mussels and the studies of mussel problems, besides
exercising wider activities in fishery investigations. For a number of
years field investigations relating to the distribution, habits, and
conditions of life of the mussels have been prosecuted by the staff and
associates of the Bureau throughout the Mississippi Basin.

For the first two years at the Fairport station mussel propagation was
carried on in an experimental way, but beginning with 1912 the
practical operations have been conducted upon as large a scale and over
as wide a territory as the available resources permitted. During the
past two years mussels have been propagated chiefly in the Mississippi
River from Lake Pepin, in Minnesota, to New Boston, Ill.; in the Wabash
River in Indiana, and in the White and Black Rivers of Arkansas. During
the year ended June 30, 1913, about 150,000,000 glochidia, or young
mussels, were put out, and in the first half of the present fiscal year
that number is fully equaled. Such figures appear large. It is not
difficult by the methods of propagation to handle considerable numbers
of glochidia; indeed, it is necessary to work on an ample scale, for in
mussel propagation, as in most forms of fish culture, what we can now
do is to aid the young over the most critical period in their life
history, after which they must be left to continue the struggle for
existence by their own efforts.

We therefore plan to work in such a way that, even with the liberal
discount that nature will surely apply to our returns, there may be
left a real measure of benefit gained without undue cost. Many of the
young will be lost from falling upon unsuitable bottoms and from many
other unfavorable conditions, such as confront every young mussel in
nature with more or less frequency. We would like to remove all of the
unfortunate conditions productive of loss, both to the mussels that we
put out and to those that are propagated entirely by natural means; but
this, of course, is not possible. There are, however, artificial
conditions which do injury to the younger mussels, and it is both
desirable and practicable to prevent such damage as far as can be done
reasonably.


      RESULTS DEPENDENT UPON PROTECTION.

In the regular fishery for mussels the beds are continually dragged
over with rakes, tongs, crowfoot hooks, or dredges. It is inevitable
that the young mussels will suffer to some extent from this process. It
is quite unnecessary, however, for the "infant" mussels, many of them
too small for any use at all and many more too small for any economical
or proper use in manufacture, to be entirely removed from the beds.
Mussels are thus uselessly destroyed that might be left to grow to a
size at which they would be both commercially valuable and properly
usable; meantime, too, they might take their natural part in the
reproduction of the species.

Furthermore, it would be desirable to leave portions of the rivers
entirely undisturbed by the operations of shelling during periods of
some years. This would accomplish a double object--it would leave the
best conditions for the natural reproduction of the remnant of the old
stock and for the growth of the young mussels and at the same time it
would create a series of reserves in which artificial propagation could
be carried on with the best conditions for maximum results. In such
closed regions the young mussels would have to contend against only the
normal unfavorable conditions which all mussels have ever had to
withstand, without an added toll of destruction being taken by the
direct and indirect effect of the operations of men.

The simple "closing" of a depleted region, if the exhaustion has not
proceeded too far, may be expected to lead to sure betterment, and even
in time, if the closure were for a very long period, to a restoration
of the former condition when mussels were so richly abundant. It will
be advisable, however, to supplement natural processes by the methods
of artificial propagation in order that the replenishment may be
hastened and a greater result gained in a shorter time. We have to
contemplate that the beds that may be closed will have to be reopened
after a definite period, for the fishermen can not afford to work
indefinitely on restricted and depleted areas, and the supply of
available shells must be maintained. A proper solution as fair as
possible to all will be found in a plan of rotation which will give
rest periods to the different portions of a river in succession. Let
this measure be supplemented as far as may be by Government or State
propagation of mussels in the resting regions.

It is apparent that artificial propagation and protection are
intimately related. Restrictive measures alone will yield benefits, but
these will be greater if the protection is followed up by well-directed
propagation. Artificial propagation pursued independently may be
expected to bring results, but the advantages will be considerably
diminished if no steps are taken to lessen the unnecessary destruction
of the young mussels thus given a start upon life.




      PROTECTION.


      ESSENTIAL CONSIDERATIONS FOR EFFECTIVE LEGISLATION.

Although at least 20 States participate directly in the mussel fishery
for the shell trade, only 2 or 3 of these have taken any action of any
kind for the protection of the resources. In some others measures have
been proposed at various times, but without receiving favorable
consideration by the legislative bodies. Indeed, it is probably well
that this is the case, in view of the fact that there has been no
general presentation of the case from all sides to aid in a just
consideration of the matter. The Bureau is prompted to make this report
in the hope that suggestions based upon a long-continued investigation
of the shelling industry in all its phases may be of material aid to
the responsible bodies concerned in the determination of how best to
perpetuate the mussel resources, giving due regard to the local
conditions involved.

Any legislation to be most effective must fulfill certain general
conditions. It must be based upon just consideration of the welfare of
all classes legitimately interested in the business, including
shellers, buyers, manufacturers, and the public generally. This is
important, not only because fairness demands it but because it is
manifestly impracticable to enforce a law which is framed in disregard
of economic requirements. A law that makes possible the creation of a
monopoly, or one that drives the buyers and manufacturers from the
territory, or that sacrifices the good of the industry to revenue
production to the State, would be so manifestly unsound that further
comment seems unnecessary.

Nevertheless, the element of sacrifice can not be entirely eliminated.
In this case, as in others, ultimate benefits can scarcely be obtained
without some temporary sacrifice, although it should be aimed to make
the immediate loss felt as little as possible. It is the unwillingness
of individuals to make voluntary sacrifices, independently, for the
good of the mussel beds that makes legislation of any kind necessary.
There is a demand for legislative action only because, in the end, the
welfare of all parties concerned is dependent upon the promotion of
abundant growth of mussels.

Finally an eminently desirable feature of any legislation is that it
shall be so simple, plain, and undebatable as to minimize the
difficulty of enforcement. Coupled with this there must be not only an
effective penalty but machinery of enforcement that will work simply
and certainly.

The measures to be proposed will be considered in the light of these
requirements, together with the basic conditions offered by the natural
history and the conditions of life and reproduction of the mussels.


      EXAMINATION OF PROTECTIVE MEASURES.


      TWO MEASURES FOR IMMEDIATE APPLICATION.

As appears from the remarks hitherto made, the restrictions which are
immediately required for the preservation of the shell resources are--

(1) The imposition of size limits for the protection of young mussels.

(2) The adoption of a plan of rotation of closed regions, whereby the
mussel beds may be given the best opportunity for propagation and
growth.

We do not at this time advocate any other limitations, and it will be
attempted to show that these are so simple to apply and so promising of
effectual conservation that it is strongly advisable not to complicate
the situation by a needless multiplicity of restrictions. These two
measures will be fully discussed in subsequent sections of the paper.


      MEASURES NOT SUITED TO EXISTING CONDITIONS.

Two other measures that have been more or less frequently proposed are
the provision of a closed season during certain months and the
restriction of the methods of taking mussels. While it is the purpose
of the present paper to discuss more especially the positive
suggestions that are offered, it is not out of place to give briefly
some of the reasons for exclusion of measures which may have been
suggested by friends of the industry with sincerity of purpose and
which are not upon their face devoid of merit. Always let it have the
first place in our minds that the one object in view is not to hamper
but to develop the mussel fishery.

_Closed season of months._--The aim in establishing a closed season for
the mussel fishery during a portion of the year is either to protect
the mussels from disturbance during a breeding season or else to
diminish the extent of the fishery by limiting its duration.

It might be very proper to protect the mussels during the active
breeding season, if such a season could be defined; but, as a matter of
fact, the various species of mussels in any particular stream have
different seasons of breeding. The mussel industry is based upon a
considerable number of species of economic mussels. There is a group
which has a short breeding term during the summer months. Such are the
species known commercially as "niggerhead," "pimple-back,"
"monkey-face," "maple-leaf," "blue-point," "three-ridge," etc. The
"washboard" seems to have an intermediate breeding term during the
early fall, though it may be that in some cases it carries its spawn
into the winter. Many of the more important species of mussels have a
long term of breeding; in the latter part of the summer and in the
early fall the eggs are deposited into brood pouches within the shell
of the female, and there, after they hatch and develop, they are
carried over the winter, to be liberated in the spring and early
summer.[A] Of this kind are the "mucket," "sand-shell," "pocketbook,"
"butterfly," and others.

[A] Possibly these mussels liberate glochidia to a limited extent
during the fall and winter; but the general statement is well founded.


In view of the variety of commercial mussel species and the diversity
of breeding seasons, it does not appear practicable to determine upon a
closed season that will accomplish its particular purpose. The Illinois
law prohibits the taking of mussels in any navigable water in that
State between the 1st day of October and the 1st day of April; but, as
illustrating how such a measure may apply in a particular case,
practically all of the mussels in the principal river of that
State--the Illinois River--are short term or summer breeders, spawning
some in June, July, and August, others in October and about that time.
Only a few carry the spawn, after its development, through the winter.

The principal objection to an enforced interruption of the fishery
during a period of months is that it deprives the mussel fishermen of
the right to earn a living by their profession during a portion of each
year. This objection has real weight, and should be overborne only by
decided advantages to be gained from a closed season.

_Restricting the methods of fishery._--The principal implements for
taking mussels are the crowfoot bar, the rake, the fork, the tongs or
scissors fork, the dip net, and the dredge. These several pieces of
apparatus are variously adapted to conditions of depth, rate of
current, and character of bottom, as well as to the aptitudes and
customs of the fishermen. Before a method should be prohibited it
should be known that it can be replaced by one of the more suitable
methods, or else that it is so positively injurious as to require its
elimination. The only implement of capture against which complaints are
generally made is the crowfoot hook, but this is the only method in
general use which is adapted for taking mussels in the deeper water,
and it is probably in more common use than any other method. Perhaps in
time improvements upon this hook will be adopted to lessen its
injuriousness, or other methods capable of replacing it will be better
known. In the light of present conditions it would work an unnecessary
hardship upon a very large number of fishermen to prevent its use,
especially when it appears that the protection of the mussels can be
accomplished by methods more equitable to all concerned.

Still other measures have sometimes been advanced looking to the
limitation of the number of shellers to be permitted to work within a
given territory or to the leasing of shelling rights. Since such
proposals have not yet been offered in connection with any properly
worked-out plan by which serious injustice would be avoided and the
interest of the public safeguarded they may be dismissed with the
remark that it is not simply the protection of mussels that is desired
but the protection of the mussels for human use without interference
with common human rights. The absence of inherent wrong in an idea does
not commend it if it carries within itself the seeds of its own defeat
by a method of application, or a want of method, that allows
opportunity for manifestly unjust and intolerable conditions to arise.

There remains to deal with the necessity for the two measures that are
advocated and to discuss the methods of application. This can be more
adequately done in distinct sections.


      SIZE LIMIT--NECESSITY AND APPLICATION.


      EXHAUSTIVE NATURE OF THE FISHERY.

The necessity for imposing restrictions upon the size of mussels to be
removed from the beds is brought out more clearly by the photographs
than could be done by any lengthy discussion. All of the shells shown
in plates I and II were actually taken for market, sold, and shipped to
the factory. The smallest ones (in the three upper rows on plate I)
were not wanted at any factory; they were bought only because the
fishermen had thrown them into the piles along with the larger shells,
"to add weight." Most of the very smallest shells, those under 1 inch
in length, are subsequently lost in handling, by falling through the
forks or otherwise wasting as they are thrown into the car or from the
car to the bin. None of the shells in the three upper rows of plate I
would ordinarily be used by any manufacturer. It is true that some of
the shells shown have had one blank cut out, and these were actually
cut at a commercial plant, but the instance was a very rare one and was
certainly unprofitable. Even if the manufacturer desired it, the
cutters will not handle shells from which only one blank can be cut,
since the waste of time outweighs the saving of material.

[Illustration: U. S. B. F.--Doc 793. Plate I.

SMALL SHELLS ACTUALLY MARKETED. ALL EXCEPT THOSE OF THE THREE LOWER
ROWS SHOULD BE LEFT IN THE RIVERS.

[About one-half actual size, which is shown in inches at right of
plate.]]

[Illustration: U. S. B. F.--Doc 793. Plate II.

LARGER SHELLS MARKETED AND ADVANTAGEOUSLY USED.

[About one-half actual size, which is shown in inches at left of
plate.]]

Consequently all shells less than about 1½ inches in length, no
matter what the quality, are thrown into the discard. _There can be no
difference of opinion as to the pure wastefulness of taking shells of
this size._

The shells shown in the illustration are not the smallest that could be
found. Some shells observed in the fishermen's boats were only one-half
inch in the greatest diameter. Out of the water these are entirely
without use. The fisherman who saves them, thinking that they add
weight to his heap, would doubtless be surprised to learn that he would
have to handle several times and clean 200 of such shells to add 1 cent
to his earnings, for it would take nearly half a million of them to
make 1 ton.

The shells in the fourth and fifth rows, counting from the top in plate
II, are used at the factories when received, and are sometimes
particularly favored where the quality is as good as in those from many
Arkansas rivers, and the shells will yield two or three blanks of 16 to
20 lines. Such blanks are of a suitable thickness and work up
economically besides having a good quality. Some of the shells in these
two rows show how blanks of 18, 16, and 14 lines are worked out, a
"line" in button measure representing the fortieth part of an inch.

The use of shells taken between 1½ and 2 inches in greatest diameter
does not, therefore, like the marketing of those under 1½ inches,
represent absolute waste, but it does denote relative waste or real
short-sightedness from the economic point of view. Shells of this size
will average about 30,000 pairs to the ton, while mussels of such a
practical size as 2½ inches will average only 15,000. The number of
blanks obtained from a ton of shells of the latter size would be just
the same as from a ton of the smaller shells, notwithstanding that only
half as many shells are handled. _We are thus, when using the smaller
shells, depleting the mussel beds at twice the necessary rate without
any corresponding advantage._


      WASTE ILLUSTRATED.

There is given below a table that will repay careful examination as
illustrating the wastefulness of using the small shells. While the
figures must be understood to be only approximate, they are based upon
careful weights and counts of a number of shells from several
localities. The shells were all "niggerheads" and were all obtained
after shipment to factories.

The first two columns show the limits of size for each lot used, the
greatest diameter being the basis of measurement.

The third column shows the approximate number of pairs of shells
composing a ton, the unit of purchase; multiplying this number by 2
would give the number of single shells per ton.

In the fourth column there is given, in the case of the critical sizes,
the number of 18-line blanks readily taken from a single shell (which
is one-half the number yielded by a pair of shells, or an individual
mussel).

The fifth column indicates the number of gross of blanks, by
computation, yielded by a ton of shells. This computation is based upon
the cutting of 18-line blanks (not the larger 20-line blanks that have
been taken from some of the larger shells in the illustration). Some of
these shells are cut excessively close to the tips, on account of
taking too many larger line blanks. It must be understood that
different sized shells are adapted for different lines of buttons. The
data herein is for comparative purposes only.

 TABLE OF SIZES, WEIGHTS, AND BUTTON PRODUCTION FOR NIGGERHEAD SHELLS
 (APPROXIMATE FIGURES).

 +-------------------+----------+-----------+-------------+---------------+
 | Longest dimension.| Number of| 18-line   | Quantity    |               |
 +-------------------+ mussels  | blanks    | of blanks   | Refer to      |
 |Greater   Less     | per ton. | per single| per ton.    | illustration. |
 | than--   than--   |          | shell.    |             |               |
 +-------------------+----------+-----------+-------------+---------------+
 | Inches.  Inches.  |          |           |   Gross.    |  Plate I--    |
 |                   |          |           |             |               |
 |   ¾       1       |  174,000 |           |             |  1st row.     |
 |  1        1¼      |  110,000 |           |             |  2nd row.     |
 |  1¼       1½      |   55,000 |           |             |  3rd row.     |
 |  1½       1¾      |   33,000 |         2 |    917      |  4th row.     |
 |  1¾       2       |   26,000 |         3 |  1,008      |  5th row.     |
 |  2        2¼      |   20,000 |         4 |  1,111      |  6th row.     |
 |  2¼       2½      |   15,000 |         5 |  1,042      |  7th row.     |
 |  2½       2¾      |   10,500 |         6 |    875      |  8th row.     |
 |                   |          |           | }           | {             |
 |  2¾       3       |    8,500 |    [B]7-8 | }Gradually  | {Plate II--   |
 |  3        3½      |    6,200 |     [B]10 | }diminishing| {1st row.     |
 |  3½       4       |    4,000 |     [B]12 | }to less    | {2nd row.     |
 |  4                |    3,200 |     [B]14 | }than       | {3rd row.     |
 |                   |          |           | }650 per    | {4th row.     |
 |                   |          |           | }ton.       | {             |
 +-------------------+----------+-----------+-------------+---------------+

   [B] At the time of making this table only a few of the larger-sized
   shells were available, so the estimates of blanks are less accurate.

It may be seen from the table that a marketable ton of niggerheads
could be composed of the shells of 3,200 or of 33,000 mussels,
according as the shells were 4 inches in length or only 1½ inches.
As a matter of fact, no marketed ton is ever composed of mussels of an
exactly uniform size; furthermore, the extremely large niggerhead
shells are very rare and generally not very desirable on account of
inferior quality and disproportionate waste. A ton of shells from a
region of depletion will also include a number of the smallest and not
strictly marketable shells.

Now, let us take a concrete illustration: Several counts of mussels
gathered by shellers in the white River near Clarendon, Ark., were made
in October, 1913; from these an average was taken that fairly
represents the catches being made at that time in that region. It was
found that 60 per cent by number of the shells taken were of a size
less than 2 inches in greatest dimension; also that a ton of shells
comprised 20,500 pairs, of which 12,300 were less than 2 inches. Now,
it is evident that if these smaller shells were returned to the bed we
would be depleting the bed less than one-half as fast as at present.
This would be the substantial advantage that such a size limit would
have to the mussel beds; and any advantage to the mussel beds is an
ultimate advantage to the fishermen, manufacturers, and all others in
any way dependent upon the perpetuation of the mussels. Under the
working of a 2-inch size limit, 60 shells out of every 100 then being
taken on the niggerhead beds of that vicinity would have been thrown
back. This seems to be asking a good deal, but not so much as at first
appears, for the undersized shells constitute only 38 per cent of the
weight or selling value of the shells taken.

On the other hand, both sheller and manufacturer would be saved the
trouble of handling over and over again an unnecessarily large number
of shells. A ton of shells (from the same locality) comprising only
those above 2 inches in greatest dimension would contain about 13,000
pairs, or 37 per cent less than the number now found in a ton (20,500),
while these shells, the smallest ones being eliminated, would produce
at least 10 per cent more buttons of corresponding sizes.


      SIZE LIMIT IN RELATION TO ECONOMY.

The figures given above are, of course, based upon counts and
computations of shells from a particular locality and must not be
assumed to have any general application, but the facts and principles
derived do have a universal bearing. If such a size limit as 2 inches
is adopted, the saving to the mussel beds and to the future of all
interested parties is out of all proportion to the immediate loss to
any party; and even the immediate loss is to some extent compensated by
the saving resulting from having to do with a lesser number of shells
that yield a greater number of buttons per ton.

Undeniably some temporary sacrifice is entailed, but unless it be
admitted that temporary sacrifice will be accepted, it is useless to
consider any manner of restriction for ultimate benefit.

There is one point that is brought out in the table on page 14 that
merits attention from the broad standpoint of economy. In all shells
there is a proportion of unavoidable waste, since the entire weight of
the shell can not be transformed into buttons. In very small shells we
may expect an undue waste, on account of the fact that only one or two
blanks can be cut out, leaving a larger bulk of shell in proportion to
the number of blanks gained. On the other hand, in very large shells a
high degree of waste is involved because of excessive thickness, which
must be ground from the blanks, and because of the extra weight of the
discarded portion. Somewhere between these extremes is the size of
shell that yields the largest number of blanks as compared with the
waste or the weight of shell that does not go into buttons. As shown by
the data in the fifth column of the table, the shells a little above 2
inches in size are those (for this species) that make the best yield
per ton for the small lines for which there is the greatest general
demand.


      REASONS FOR THE PROPOSED 2-INCH LIMIT.

Argument might be made in favor of a higher size limit as being still
more favorable to the preservation of the mussels, but it is sufficient
to say that the economic conditions would not justify a higher limit.
At 2 inches a sufficiently severe restriction is placed upon the
fishery, and to go further would be practically to prohibit the pursuit
of shelling in so many localities that excessive hardship would be
caused.

As consideration thus far has been given almost exclusively to the
niggerhead shell, the question may well be raised, Will the same limit
apply to other species of shells? The minimum size of 2 inches
suggested can be taken as an absolute minimum, since there is no
species of any importance for which it would be too high. This minimum
would not, however, give the same degree of protection to the larger
forms, such as the washboard, the bluepoint, and the mucket. Should a
minimum size be fixed with particular reference to any one of these
varieties, it would necessarily be a good deal higher.

In the present paper recommendation is made for this one-size limit
alone, for the following reasons:

1. All conditions considered, it is the most appropriate limit that
could be designated for the niggerhead mussel, which is at present the
most important species of wide distribution, and which is, furthermore,
the species most liable to rapid extermination. This and species
closely like it, as the pigtoe, the pimple-back, and the maple-leaf,
are chiefly those that are now being taken in the very small sizes.

2. The same size applies equally well to the related species just
mentioned, as well as to the "hickory-nut," or "Missouri niggerhead,"
and the "butterfly."

3. The larger species, as the "washboard," "bluepoint," and "mucket,"
are generally so evidently valueless in the small sizes that shellers
do not take them. At least it is not yet of observation that particular
injury is being done to these species in this way.

4. To insure the least trouble of enforcement of the law, it is
necessary that a minimum size be set, below which no shells of any
species may be retained. There are many different species of commercial
mussels, and some of them so intergrade as to make exact determination
a nice matter in some cases. Distinct size limits for the different
species would introduce peculiar difficulties into the practical
workings of enforcement; it would be more troublesome to the sheller to
observe the law voluntarily, and loopholes for evasion would more
easily be found by the offender of wrong intent.

Should conditions in certain States or streams subsequently require a
higher limit for particular kinds of shells, a supplemental limit may
be fixed for designated species; but this could be done without
affecting the application of a 2-inch limit as an absolute or universal
limit below which no shells of any species could be lawfully taken. It
is desirable that few different limits should ever be used, and it
seems expedient to have but one size limit until the first legislation
shall have been tried out.

      DETAILS ESSENTIAL TO EFFECTIVE LEGISLATION.

In concluding this section emphasis may be laid on the value of certain
details of legislation.

_Allowable margin of undersized shells._--While it may seem desirable
that no undersized shell at any time should be taken away, nevertheless
it is necessary to make allowance for a margin of unintentional error.
Only if the shellers and buyers were to apply an instrument of measure
to each individual shell would all possibility of error be eliminated.
The sheller will naturally, after a few measurements, come to judge by
the eye, and it is desirable that the law should be somewhat liberal,
rather than too stringent in the allowance for mistakes. There should,
accordingly, be a supplemental provision that if not more than 5 per
cent of the shells by number (not by weight) of any bushel are found to
be below the size limit, the law shall not be presumed to be violated.

_Illegal possession._--To be practicable of enforcement, the law should
be so worded as to make it illegal not only to bring ashore or to offer
for sale, but also to have in possession, fresh-water mussels or clams
of a size less than 2 inches in greatest dimension. This one provision
will obviate much unnecessary expense, as well as undesirable
complications in the detection of violations and the prosecution of
offenders. Furthermore, since buyers of the shells would be equally
liable to prosecution, the effect would be to destroy the market for
undersized shells, and thus in the most effective way to restrain the
shellers from taking them.

_Method of measuring mussels._--It will be noted that the method of
measure is stated as "in greatest dimension," with a view to
eliminating every possibility of uncertainty or difference of opinion.
Mussels are sometimes measured in length or width or height, but on
account of the irregular form of mussel shells these dimensions are not
always interpreted in the same way. In testing the blank-making
capacity of a shell, commercial men sometimes measure the "width on the
face"; that is, between the lateral hinge tooth and the lower margin of
the shell. This measure can of course only be taken from an open shell,
and therefore could not serve for our purpose. It is worth while to
call attention to the fact that a 2-inch shell as measured in greatest
dimension would be a good deal smaller than a 2-inch shell in
commercial measurement.

An inspector would need to be equipped with an ordinary rectangular
caliper. If a shell should be found to measure more than 2 inches in
any linear direction it would be considered as above the size limit.


      CLOSED REGIONS--NECESSITY AND APPLICATION.

In addition to the provision of size limits it is strongly recommended
that certain portions of the rivers be closed for rest periods covering
several years. It might be thought that in regions of extreme depletion
the operation of a size limit would, by making the fishery less
profitable, have the effect of causing a practical rest period, but
this can not be expected, for, stimulated by the high price of shells
and the ever-present hope of making a pearl find, the local shellers
will hardly ever desist entirely from the fishery.

No better way of giving protection to mussels can be found than that of
entirely stopping the shelling upon a series of beds, although the plan
must be applied in such a way as not to reduce the supply of mussels
unduly and suddenly and with as careful regard as possible to the
established interest of communities.


      INJURY TO SPAWNING MUSSELS AND TO YOUNG.

Some of the conditions that make a system of closed regions
particularly advisable for the conservation of fresh-water mussels may
be briefly mentioned:

1. It has been previously stated that some of the mussels are spawning,
or with spawn, during any period of the year. Many of the most
important species are spawning during the late spring, early and mid
summer; other equally important species form their eggs in the late
summer, when they become fertilized and develop into the glochidium
stage, but the mother clam retains them in marsupial pouches within her
shell during the entire winter and even into the summer. All species of
mussels carry the eggs in the marsupial pouches during the process of
development to the glochidium stage or longer, whether the period be
for a few weeks or for a few months. In this condition the mussels are
said to be gravid. It is readily observed that when gravid mussels are
disturbed they frequently discharge the young, regardless of whether
these are mature enough to be liberated from the parent or not; certain
species, such as the niggerhead, are particularly likely to do this.

In the commercial fishery, therefore, not only is much spawn destroyed
when large gravid mussels are captured, but it is quite probable that
other mussels, disturbed on the bottom, though not captured, are caused
to abort the young in an immature stage when they are entirely unable
to complete the development without the parent.

2. In the stage of existence immediately after liberation from the
parent, the young mussels are parasitic upon fish. We are not here
concerned with them during this period of the life history. When they
are dropped from the fish many of the young mussels do not at once take
up life in the sand or mud of the bottom, but we find them forming
delicate threads by which they hang from plants or sticks or stones or
from clam shells, and thus are kept from being washed away or smothered
in the mud of the bottom. We may imagine the harm to these little
mussels that is unavoidably wrought when the beds are continually
dragged over. In like manner, the little shells that are just beginning
to take hold in the bottom may be torn out by the rake or hooks, to be
smothered or washed away to less favorable bottoms. It will be
remembered that when mussels first begin life in the thread stage or in
the bottom if the thread stage is omitted, they are too small to be
found without a microscope.

3. One of the principal methods of capturing mussels is with the bar
and hooks dragged over a large area of mussel bed in taking a
relatively small number of shells. There is chance for these hooks to
injure many little shells when each drag, requiring a period of only a
few minutes, covers a space of bottom 16 feet wide and several hundred
feet long. Nevertheless, it is not certain that there is any method to
take its place, and any implement used will accomplish some injury to
the very youngest mussels.


      CONSIDERATIONS DETERMINING SIZE OF CLOSED REGIONS.

In planning for the closing of portions of rivers for periods of years
consideration should be given to community needs as well as to general
economic and biological conditions. On the one hand, the closure will
be more effective in result, as well as easier of enforcement, if the
regions of closure are made very large; while, on the other hand,
making the closed regions smaller might cause less economic
inconvenience. If, for example, the entire Illinois River should be
closed to mussel fishery for a period of several years, there might be
a substantial uncompensated loss to some communities, where there are
factories employing labor to cut shells derived from that river. On the
other hand, should we divide the river up into small sections of 2 or 3
miles in extent, some of which would be open while others would be
closed under the law, it is apparent that such a plan would be almost
impossible of enforcement. To prevent shelling from being carried on in
all these little, closed areas would require a force of wardens and an
expense entirely incommensurate with the object to be gained.

It is held advisable to divide a river within a single State into some
four or six sections for the purpose of establishing closed regions.
One-half--that is, two or three--of these sections, taken in
alternation, could be ordered closed for a period of five years, during
which no mussel fishing at all should be allowed in the closed
sections, although it would be regularly prosecuted in the alternate
portions of the stream. It would be convenient to break a river at
points where there was a substantial community interest in the
shelling.


      PRACTICABLE DIVISION OF RIVER SYSTEMS ILLUSTRATED.

For example, let us apply this method of dividing a stream to the White
and Black Rivers in Arkansas. Starting from the head-waters of the
Black River, we find the first center of economic interest at Black
Rock, another on the White River at Newport, and a third at Clarendon.
Now, the river might properly be broken at these points, forming four
main sections. The fishery might then be entirely prohibited for
several years from the mouth of the river to Clarendon, while permitted
from Clarendon to Newport, and again prohibited from Newport northward
to Black Rock on the Black River, and to Batesville or other suitable
point on the upper White, while permitted from Black Rock and
Batesville northward on all the tributaries. We would have the river
system divided into four sections, which would be probably as nearly
equivalent as could be expected. Furthermore, none of the three towns
mentioned would be cut off from the local supply of shells, except in
one direction.

The shellers, generally speaking, would be little affected, since, with
their house boats, they could move from one portion of the river to
another. Those shellers who do not use house boats, but are local
residents and go out only by day from their homes, would be most
affected, and it is these generally who are most in favor of closing
portions of a river. They recall how much more easily shells were taken
in past times when the shells were abundant, and they would be willing
to do something else meantime in order that the beds may be given a
rest and the shells again become numerous. Shelling has no attraction
over any other form of crude labor when the shells are so scarce that a
wage can scarcely be made.

Taking the St. Francis River in Arkansas as another illustration, the
river might be broken at Madison, Parkin, and Marked Tree. It is true
that there are not many mussels, according to report, above Marked
Tree, but the region between Madison and Parkin has beds which may well
balance the remainder of the river.

The Wabash River, Ind., is one in which the need for protection is most
evident; and this stream could be divided at Vincennes and two other
points selected with reference to their economic interest in shelling
and with regard to an equitable division of the river system.

It might seem that an ideal method of rotation would be based upon the
division of a system into six portions, only one of which should be
worked in any one year; a new portion would be opened each year, while
each territory would enjoy a rest period of five years between
successive "open" years for that particular territory. It will be
evident that such a scheme, however correct in theory, would be
entirely impracticable. The plan of keeping certain regions closed for
periods of years while other regions are worked continuously during a
corresponding period of years may have some imperfections, but it is
probably the best that can be worked out without practically suspending
the industry. Undoubtedly the plan will work most efficiently if a
proper discretion is used in its application.


      PROCEDURE FOR ESTABLISHING CLOSED REGIONS.

The law should plainly stipulate and establish the principle of the
closure of the rivers by regions or sections, but the determination of
which specific sections are to be closed should be left for
determination after investigation by properly qualified authorities.

A comparatively simple plan may be suggested under which the most
careful consideration could be given to the local conditions involved
as well as to the rights of the State as a whole. The legislature could
authorize and instruct the proper State authorities, as the State fish
commission, to give due consideration and study to the needs of the
mussel industry and determine what portions of the streams of the State
should be closed to the mussel fishery for a period of years. It could
be further provided that, after the preliminary determination of plans
for closure, due advertisement should be made in all regions affected
and opportunity given for public hearings in such regions, after which
the commission should submit its final recommendations to the governor
of the State, who should then issue a proclamation ordering the entire
interruption of a mussel fishery in the regions selected for closure.
The original legislative act should provide that the proclamation so
made should have the full effect of law, and should specify the
penalties that would be incurred by violations. It is desirable also
that the governor, upon recommendation of the commission, should have
power to reopen the closed regions when such action was judged
necessary.


      ENFORCEMENT OF THE LAW.

_Powers of officers._--It is necessary not only that the duty of
enforcement of the law be assigned to specified State officers, but
also that they be expressly given the right to inspect and examine
mussels or shells in the boats or on land and be empowered to seize
mussels or shells held in violation of the law. It is practically
impossible to bring about convictions when the opportunity is allowed
for destruction of the evidence between the time of detection and the
date of trial.

_Permits for special cases._--In cases where for the purposes of
investigations it may be necessary to take small mussels, the State
officers charged with the enforcement of the law should have by law the
right to issue special permits for the taking of undersized mussels for
scientific uses and not for sale.

_Expenses of mussel protection._--The plans which have been advanced in
this report can be carried out with a minimum of expense. The
simplicity of the measures would reduce the trouble and cost of
inspection to the smallest practicable figure. The assignment of the
duties of enforcement to existing State commissions or boards which
already have field deputies or wardens obviates the creation of any
special offices for execution of the mussel laws.

The question of whether steps should be taken to raise special funds on
account of the additional burdens that would be placed upon the present
boards is one that would be determined by each State in the light of
its own conditions and established customs. It would be very
undesirable to create a burdensome tax; to do so would only react
against the State, and in the end the tax would be paid by the
shellers, who are now making only a meager living, for the local
shellers would have to sell in competition with the shellers from
States where more liberal conditions prevail.

It is another matter, however, to require a nominal license fee for the
privilege of working upon the public mussel beds. Such a fee need not
be greater than $1 or $2 per season, an amount which could be paid by
anyone who wished to shell seriously. Perhaps the idea of a fee of any
kind would arouse some antagonism among a certain class of shellers who
would enjoy the public stores without return of any kind. Some shellers
favor such a license system, and the writer believes that they must all
eventually come to see that it works to their own particular advantage
in many ways. It tends to create a class of professional shellers,
besides providing the necessary means for promoting the abundance of
shells.


      SUMMARY OF RECOMMENDED LEGISLATION.

The legislation recommended for protection of mussel beds, based upon
the considerations discussed in the preceding pages, may be summarized
as follows:

   I. (_a_) A single size limit should be fixed as applicable to
       all shells taken. The minimum size here proposed is 2 inches.

      (_b_) The method of measuring the shell should be defined as
      "in greatest dimension."

      (_c_) Possession of undersized shells, whether or not sold or
      offered for sale, should be illegal.

      (_d_) There should be an allowable margin of undersized
      shells for unintentional violation.

  II. (_a_) Alternate portions of rivers or river systems
      should be closed for a period of years, to permit
      recuperation of mussel beds.

      (_b_) The units of division of a river system should be large
      enough to make enforcement practicable with least expense.

      (_c_) The river would conveniently be broken at the few
      points where there is most community interest involved in the
      shelling.

      (_d_) Approximately five-year periods of closure are
      recommended, with some discretion allowed to executive
      officers as to duration of period.

      (_e_) Closed regions should be established by proclamation of
      the governor of the State, after expert examination of the
      mussel beds and after public hearings on the subject in the
      communities affected.

 III. (_a_) Officers charged with enforcement of the law
      should be empowered to examine mussels or shells in boats or
      on land and to seize the catch in case of violation, as well
      as to arrest or cause arrests to be made.

      (_b_) Provision should be made for the issue of permits for
      the taking of mussels of any size or in any region for
      scientific uses and not for sale.