MIGRATION OF FISHES
53
and Goldsborough write,
“
If they enter
at all
they are apt to run up the
tributary stream which
they reach.”
-
.'
_
…
&
_
'
On the whole, it may be said that the run of Salmon up
the‘;rivers is connected with spawnihg,yet Someimportant
exceptions have to be made: Many specimehs will go some
'
distance up a river only to turn back (and this may'happen
several times), or even remain “months in denitelÿ“frlesh
water before proceeding to spawn.- There may be a simple
explanation of these eccentricities ; it must be remembered
that the Salmon is: not far from
a
freshwater sh-.
According ”to Patou and Newbigin (1900) the factor
determining migration from sea to river is not the “ m'sus
‘
generations, but the state of
The spawning
'
comes
,
.
«
.
.
‘;With:the Salmon we Jr_nay nish this account of the
ohe‘$trèam
shes, those which journey “from
deeper tOshaHOWer and even fresh water in Order to full
their: life, purpose. -_ This is by far—the most common
form of migration
a Very:xlarge number of marine shes, ,
even the Sharks, Skates, and Rays, follow in,-.theïiain
the same course, , As suggested
the Îerm
“_ anadromoüs,” formerly used-Only =for _th0se entering fresh
water, maywel—lbe
all those
-
the same general rule in their. ngration,'narnely, ,an_ .aSCent
from deeper.- to shallower
.Toa—Ïvery large eXt'ent;
this at once indicates the nature:of the problem to be solved_
'
and even suggests the solution.
_
But there are two groups of apparent exceptions.
'
one thé; shes exhibit but little tendency to —undertake any ,
spawning migrations. They spawn, as it were, where they ;
_
,
nd themselves. This applies naturally
the
_" {
shes, though even
these
migration can “be noted.’ ThuS,
_
’
Butter—sh. or: Gunne1fhas_,aç—shojr—t‘;;;anaäl‘romouis;_m_igratfiatr…' .
'
of a’feWï miles; WhÎÏS'Ç- the
1*Qg9ëh ShOWS
'
Ï
*
ngrat—iohin
Among—the
,
agam;_‘mps‘ç Species preferthèdçépWätef for--Îspawningsrbut
'
__
*
: