326
THE BIOLQGY OF FISHES
the quality and rate of growth of the sh. The question is,
1
therefore, whether nature can provide an optimum quality
and quantity at the same time or whether man’s assistance
is necessary
to regulate the complicated matter. Petersen
7
has recently found in the Belts of Denmark that an intensiVe
shery has led for a time to an increase in'the annual catch
and rate of growth of the largerPlaice.
'
,
'
.
One of the strange paradoxes frequently met within .—
nature has arisen from the intensive study of these questions
,
during thefpast twenty years. As mentioned above, it Was
formerly thought that the removal of the large. sh, by
_.
dinnishing the number of
would diminish
-
the supply of young fry. But it has been found that the
-'
.
_
young fry are actually too abundant and crowd one-another
on the nursery grounds
such an “extent that there is not
enough food for all. Possibly the amount of food varies
from year to year. Hence we have to recognise that the
'
removal of large quantities . of young
_
wasteful it may seem—can be compared. for the present at
_
_
least,
the gardener’s thinning out of his youngcarrots
and onions, etc.,in the spring-time or,_ as* Petersen has .it
(I,—921), to
a lawn which is cut_many times, per year, in lieu
…
—
of Once-everysecond year.”
,
_”
__
'
,:
Ï
.
.
Another example of the complicationsto be faced —by
'
_
investigators of these problems may just be mentioned.
ln theory the proportion of the sexes of the Plaies-”should be
equal and the samples taken by
'
”
in the North Sea have yielded cômparative'equitÿ.,—‘ÏÏ'lut
Â
‘
We
not know thattheory and =piÿîacticei agree; From the
_
proportions among the
North Europe
,
it is possible that the
outnumberithe, females_in the
_
proportion of 2_or,3 to gt,-.Ï An analysis of the catches made
,
by Lowestoft traWlèfsdürir—rg' the winter m0nths, the season
-
when
after oshore, has given
'
:
,
the proportion of about 7 males to 1 female.
,
Which result
are; we to believe
But, it should be noted, the males and
femalesdoïnot behaÿ‘e in the same way; the males mature
;
;and
outw‘ards
the, nursery. grounds
THE BIOLQGY OF FISHES
the quality and rate of growth of the sh. The question is,
1
therefore, whether nature can provide an optimum quality
and quantity at the same time or whether man’s assistance
is necessary
to regulate the complicated matter. Petersen
7
has recently found in the Belts of Denmark that an intensiVe
shery has led for a time to an increase in'the annual catch
and rate of growth of the largerPlaice.
'
,
'
.
One of the strange paradoxes frequently met within .—
nature has arisen from the intensive study of these questions
,
during thefpast twenty years. As mentioned above, it Was
formerly thought that the removal of the large. sh, by
_.
dinnishing the number of
would diminish
-
the supply of young fry. But it has been found that the
-'
.
_
young fry are actually too abundant and crowd one-another
on the nursery grounds
such an “extent that there is not
enough food for all. Possibly the amount of food varies
from year to year. Hence we have to recognise that the
'
removal of large quantities . of young
_
wasteful it may seem—can be compared. for the present at
_
_
least,
the gardener’s thinning out of his youngcarrots
and onions, etc.,in the spring-time or,_ as* Petersen has .it
(I,—921), to
a lawn which is cut_many times, per year, in lieu
…
—
of Once-everysecond year.”
,
_”
__
'
,:
Ï
.
.
Another example of the complicationsto be faced —by
'
_
investigators of these problems may just be mentioned.
ln theory the proportion of the sexes of the Plaies-”should be
equal and the samples taken by
'
”
in the North Sea have yielded cômparative'equitÿ.,—‘ÏÏ'lut
Â
‘
We
not know thattheory and =piÿîacticei agree; From the
_
proportions among the
North Europe
,
it is possible that the
outnumberithe, females_in the
_
proportion of 2_or,3 to gt,-.Ï An analysis of the catches made
,
by Lowestoft traWlèfsdürir—rg' the winter m0nths, the season
-
when
after oshore, has given
'
:
,
the proportion of about 7 males to 1 female.
,
Which result
are; we to believe
But, it should be noted, the males and
femalesdoïnot behaÿ‘e in the same way; the males mature
;
;and
outw‘ards
the, nursery. grounds