River Falls journal. [volume] (River Falls, Pierce County, Wis.) 1872-2019, 1905-11-02
TAG CRUSTACEANS.
GOVERNMENT SCIENTISTS MARK
CRABS ANDLoBSTERS.
Method Adopted for the Purpose of
Tracing observation-disclosures
ments of Fisheries
Bureau.

ments of Fisheries
Bureau.
Ingenious government scientists
have devised a novel and curious
means of keeping track of the move
ments of marine animals-such, for
example, as the edible crab, whose
perambulations in it's native waters
have been found worth studying, says
the Chicago Chronicle. 1t has been
ascertained that, for some unknown
reason, nearly all of the female crabs
in the Chesapeake are in the lower
bay-a fact in all probability having
something to do with the density of
the water-and the United States
fisheries bureau wants to learn
whether any migration occurs, of
males or females, and, if so, at what
season of the year. Information on
this point might be useful in the ex-
periments now contemplated for
breeding these crustaceans, which are
threatening to become scarce, arti-
fcially.
1t is proposed to catch few dozens
OF both sexes and fasten securely to
each specimen a small copper tag
bearing a number, thereupon restor-
ing the animals to their freedom.
Each tag would also bear request
for its prompt return to the fisheries
bureau at Washington by anybody
CHANGING to capture the wearer The
tags being numbered consecutively
and memoranda being kept of the
place at which each crab was liber-
ated, the journey made by the crab
between the date of consigning it to
the water and the date on which it
was caught would be exactly known.
This method has been practiced
with considerable success in the
cases of Holsters, 479 of which were
liberated recently in Buzzards Bay
and adjacent waters. Notwithstand-
ing the fact that the Greek and Por-
tuguese fishermen who own most of
the lobster pots in that vicinity were
disposed to retain the tags in their
possession for use as charms, rs were
returned. When the data thus sup
piled were reckoned out much useful
knowledge about the movements of
the animals was secured and Incl
dentally it was discovered that these
crustaceans are much more rapid
travellers than had been supposed.
Some OF those released were found to
have jonrneyed ten miles or more
within 48 hours.
One naturally thinks of the lobster
as slow-moving creature. 1t is such,
indeed, On land, but in the water it
can not only run with great rapidity,
would do credit to a fish. 1t is
known that loDsters migrate from
the shadows to the deeper water in
winter to escape the cold, returning
shoreward in the spring; but it is
likely that they travel at other times
in pursuit of the food of which they
are most fond-such, for instance, as
the shellfsh, which they crush with
their powerful claws. A lobster, of
course, has one claw for crushing and
another for cutting, the two being
quite unlike in structure, as anybody
hay see for himself.
The tags were fastened to the lob
sterS' noses. When experiments were
made by the fisheries bureau, not
long ago, for the purpose of keeping
tab on salmon after they went to sea,
the pieces of copper were attached,
necessarily, to the back fins of the
fishes. The salmon, as everybody
knows, is a deep sea fish, which runs
up the rivers to spawn. Matched in
the upper waters of a stream, the
young salmon makes it's way to the
ocean and stays there until it is
ready to reproduce it's species. But
what does it do meanwhile? How far
does it go away from the mouth of it's
native river? How old is it when it
seeks fresh water to spawn? These
were one or two of the questions
which the experts were unable to
answer
BY tagging many of the young
fishes, however, and liberating them.
the requisite information was OBJ.
tanned with the utmost accuracy.
Each tag bore a date showing the age
of any adult fish salmon that was aft
erward caught thus ticketed. The age
of spawning was found to vary good
deal with the species, but the tags
used in number of rivers on the west
coast proved that these finny crea.
lures never go far away from the
mouths of the streams in which they
were Matched and to which they re-
turn when they are old enough to
breed. Some of the tagged salmon,
by the way, were caught in the deep
sea off the coast by fishermen.
1t used to be supposed that shad
made an annual migration up the At
lantic coast, entering the rivers sue
cessively as they proceeded north.
ward; but now it is known that they
spend most of the year, like the salm-
on, in the deep sea off the mouths of
the rivers in which they were Matched,
feeding on the bottom and never go
ing very far away. When they are
old enough they enter the rivers to
spawn. Perhaps some more facts OF
interest and value might be ascer-
tanned about the shad by utilizing the
tagging plan with them.
Some Physical Facts.
A persons eyes are out of line in two