90
THE SEAS
species.
It is, so to speak, a meeting ground of the two
”
great areas and certain shes common. to both occur.“
‘
Besides the herring and the cod, both northern repre"
_sentatives, we have, for instance, the pilchard, and occasion—
ally the red-mullet and the ahchovy, shes which are typical
of the warm waters of the Mediterranean and Atlantic.
'
Within the large areas, also, it is to be noticed that there
are further sub—divisions; certain shes which live in the
very cold part of the Norwegian Sea, and in the Arctic
are
quite characteristic of those regions.
_
,
.
In the tropics, again, the sh population is quite character- '
istic, and here are to be found many of the most brilliantly —
coloured shes in- the world.
.
'
In the geographical. distribution of shes, apart from
_
these differences caused by temperature, there are also
dierences that are occasioned by the depth of the water.
'
There
are
shallow—water shes, deep—water shes, and
abyssal shes, that is, shes who live on the very at plains
in the
parts of the oceans known as the abyss.
.
.
It is natural
shes which will be limited'to ,
certain areas by depth boundaries are those that live most
_
of their time swimming on, or clo'se to, the sea bottom itself.
Ï
'
Fishes such as herring and» mackerel (so-called pelagic
shes), can have a much wider area over which to mam,
because, swimming as they always do in the upperwater
_layers, they can keep to the depths they most prefer,
‘
irrespective of at-what depth the actual bottom of the sea
‘
may be.
_
.
,As ,eXamples of sh whose distribution is limited by .“
.
depth, we can name the plaice, which lives in the com—
paratively shallow at areas Such as the North Sea; the
hake,
that roams along the deep-water Shelf from one to ve
hundred fathoms, that ‘œnstitutès the continental slope; ‘
and that. curious sh of the cod family known as the
THE SEAS
species.
It is, so to speak, a meeting ground of the two
”
great areas and certain shes common. to both occur.“
‘
Besides the herring and the cod, both northern repre"
_sentatives, we have, for instance, the pilchard, and occasion—
ally the red-mullet and the ahchovy, shes which are typical
of the warm waters of the Mediterranean and Atlantic.
'
Within the large areas, also, it is to be noticed that there
are further sub—divisions; certain shes which live in the
very cold part of the Norwegian Sea, and in the Arctic
are
quite characteristic of those regions.
_
,
.
In the tropics, again, the sh population is quite character- '
istic, and here are to be found many of the most brilliantly —
coloured shes in- the world.
.
'
In the geographical. distribution of shes, apart from
_
these differences caused by temperature, there are also
dierences that are occasioned by the depth of the water.
'
There
are
shallow—water shes, deep—water shes, and
abyssal shes, that is, shes who live on the very at plains
in the
parts of the oceans known as the abyss.
.
.
It is natural
shes which will be limited'to ,
certain areas by depth boundaries are those that live most
_
of their time swimming on, or clo'se to, the sea bottom itself.
Ï
'
Fishes such as herring and» mackerel (so-called pelagic
shes), can have a much wider area over which to mam,
because, swimming as they always do in the upperwater
_layers, they can keep to the depths they most prefer,
‘
irrespective of at-what depth the actual bottom of the sea
‘
may be.
_
.
,As ,eXamples of sh whose distribution is limited by .“
.
depth, we can name the plaice, which lives in the com—
paratively shallow at areas Such as the North Sea; the
hake,
that roams along the deep-water Shelf from one to ve
hundred fathoms, that ‘œnstitutès the continental slope; ‘
and that. curious sh of the cod family known as the