68 REPORT OF COMMISSIONER OF FISH AND FISRERIES. 
34 feet high) to practice the process, which will be in operation before 
the close of 1877, with the special object of making artificial fish-flour 
and dried powders for fertilizing purposes. In this process they expect 
to work up a great number of refuse fish, which they promise to pur- 
chase at the same price as menhaden and in the following order of prefer- 
ence: Bluefish, porpoises, sharks, dogfish, menhaden, and skates. They 
propose to work up twenty tons of fish each day, and to employ from one 
to three steamers to cruise for these supplies, extending from Block Isl- 
-and to the coast of Maine, touching all intermediate points. 
The extent of destruction to fish caused by the porpoises, skates, and 
dogtish is well known, and should the anticipated manipulation of forty 
thousand pounds of refuse fish per day be accomplished, or say twelve 
millions per year (counting three hundred days to the year, and allow- 
ing ten millions of pounds for the destructive kinds), we shall have an 
enormous withdrawal of predatory fish from the scene of action. This 
aggregate might be considered as equivalent in destroying capacity to 
two millions of bluefish at five pounds each; and an estimate of the 
amount of fish that would be devoured by such a body has been given 
in my first report. if the success anticipated for this venture be real- 
ized, it is probable that other establishments of a similar kind will be 
started, constituting a still greater relaxation of the exhaustion of the 
yield of fish. A few years of such fishing should present a marked in- 
fluence upon the supply of edible fishes along the middle and northern 
coast of the United States. 
3. NATURAL CAUSES OR CHANGES. 
Vish as a class are quite subject to fatalities arising from natural 
causes, and which sometimes operate on a very large scale. Among 
these, volcanic eruptions are not the least momentous. It very fre- 
quently happens that such phenomena from volcanoes near to or in the 
sea are accompanied by discharges of boiling water or of poisonous 
gases, which contaminate the waters and cause great distruction to 
animal life therein. Many cases of this character are on record as in- 
cidents in the history of voleanie discharges. Not unfrequently mud 
is thrown out in vast masses, which fills lakes and streams, or invades 
the edges of the ocean with disastrous consequences to life. Violent 
storms and hurricanes are also to be considered in this connection, fish 
being not unfrequently blown on the shores or taken up bodily and car- 
ried to a great distance inland. Sudden changes by winds and currents 
of the sea bottom not unfrequently cut off portions of the sea occupied 
by large bodies of fish, which, unable to get back to proper physical 
surroundings, soon perish. Very often, too, this action of the winds 
and waves renders the waters very turbid and unfit for animal life in 
the sea, which is consequently speedily destroyed. Of this, striking 
illustrations will be given in a succeeding chapter. 
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