14
J. E. SHELBOURNE
to provide protection for salvaged spawn, during the delicate embryonic
stage, by rearing within the confines of a hatchery.
We now know that there is no strict relationship between egg
production and brood strength for those marine fish possessing a high
fecundity and a pelagic larval phase. Hjort (1914, 1926) suggested
that the final size of a year class of cod and herring is determined
shortly after hatching and is related to the larval food supply and
drift. Sund (1924) supported this view. Johansen (1927), investigating
yearly fluctuations in the abundance of fish larvae in Danish waters,
came to the conclusion . . . “ that in cold winters, when there is a
relatively marked outflow of comparatively fresh water from the
Baltic, through the Belts and Southern Kattegat, the tiny plaice
larvae fail to obtain sufficient nourishment and die of starvation
en mmse.”
The study of population dynamics w a in its infancy when the
marine hatchery movement began. Fish culturists maintained that the
problem of declining fisheries could best be solved by achieving maximum output of newly-hatched larvae for the lowest possible cost.
Annual production was measured in terms of millions of fry released ;
in moet reports the numbers were impressively “ astronomical ”.
Some sceptics called for proof that marine hatcheries were substantially
incretlsing the abundance of fish. They were answered with “ hearsay ”
evidenoe, usually collected from local fishermen. Only two attempts
were made to substantiate these claims experimentally : one in Norway
and the other in Scotland.
A. Hearsay ” evidence
As early tls 1883, only 6 years after the first experimental liberation
of ood fry, the U.S. Fish Commission reported the appearance of
grey cod of a size not previously seen in coastal waters around Gloucester
Harbor. They were generally accepted aa the fruits of hatchery effort,
and became known locally as “Fish Commission” cod. Ravenel
(1900) attributed the great increase in cod take on the New England
coast during 1899 to artificial propagation. Ewart (1885) and Herdman
(1899) reiterated hearsay evidence from the New WorId in their efforts
to establish commercial sea-fish hatcheries in Britain. Herdman
reoeived a letter from the U.S. Fish Commissioner in 1898, which read :
‘‘ For about ten yeam the cod work haa been attended with marked
BUOO~RS, and in Mwmchusetts h a resulted, not only in establishing
the inshore ood fbhery on grounds long exhausted, but through favourable distribution of the fry, in extending the fishery to other waters
not originally frequented by the cod. . . . Some investigations made
J. E. SHELBOURNE
to provide protection for salvaged spawn, during the delicate embryonic
stage, by rearing within the confines of a hatchery.
We now know that there is no strict relationship between egg
production and brood strength for those marine fish possessing a high
fecundity and a pelagic larval phase. Hjort (1914, 1926) suggested
that the final size of a year class of cod and herring is determined
shortly after hatching and is related to the larval food supply and
drift. Sund (1924) supported this view. Johansen (1927), investigating
yearly fluctuations in the abundance of fish larvae in Danish waters,
came to the conclusion . . . “ that in cold winters, when there is a
relatively marked outflow of comparatively fresh water from the
Baltic, through the Belts and Southern Kattegat, the tiny plaice
larvae fail to obtain sufficient nourishment and die of starvation
en mmse.”
The study of population dynamics w a in its infancy when the
marine hatchery movement began. Fish culturists maintained that the
problem of declining fisheries could best be solved by achieving maximum output of newly-hatched larvae for the lowest possible cost.
Annual production was measured in terms of millions of fry released ;
in moet reports the numbers were impressively “ astronomical ”.
Some sceptics called for proof that marine hatcheries were substantially
incretlsing the abundance of fish. They were answered with “ hearsay ”
evidenoe, usually collected from local fishermen. Only two attempts
were made to substantiate these claims experimentally : one in Norway
and the other in Scotland.
A. Hearsay ” evidence
As early tls 1883, only 6 years after the first experimental liberation
of ood fry, the U.S. Fish Commission reported the appearance of
grey cod of a size not previously seen in coastal waters around Gloucester
Harbor. They were generally accepted aa the fruits of hatchery effort,
and became known locally as “Fish Commission” cod. Ravenel
(1900) attributed the great increase in cod take on the New England
coast during 1899 to artificial propagation. Ewart (1885) and Herdman
(1899) reiterated hearsay evidence from the New WorId in their efforts
to establish commercial sea-fish hatcheries in Britain. Herdman
reoeived a letter from the U.S. Fish Commissioner in 1898, which read :
‘‘ For about ten yeam the cod work haa been attended with marked
BUOO~RS, and in Mwmchusetts h a resulted, not only in establishing
the inshore ood fbhery on grounds long exhausted, but through favourable distribution of the fry, in extending the fishery to other waters
not originally frequented by the cod. . . . Some investigations made