THE ARTIFICIAL PROPAQATION OF MARINE FISH
75
then it might be possible to rear a plaice or sole to marketable size
in less than 2 years, compared with the usual 5.
The natural diet of the plaice includes small molluscs and marine
worms, Mussel (Nytilus edulis) culture on a large scale should present
no speoial difficulties ; it is not beyond the realms of possibility that a
oheap manufactured food based on fish offal or agricultural by-products,
with balanced additives, would be acceptable to marine fish in fattening
ponds.
Regarding those species most suitable for pond culture, flatfish, in
my opinion, give the best prospects of success-particularly the plaice,
sole, lemon sole and turbot. Flounders, witches and dabs enjoy a,
limited market. Our pelagic food-fish are more difficult to rear in tanka,
and one wonders whether the effort required would be covered by the
value of such fish on the market.
Stock selection for fast growth and other desirable market charmteristics would be most rewarding when the selected strain is destined
to complete its life in an artificial, protected environment. It may be a
muoh more difficult taak to select, from hatchery-rear- stock, those
strains best fitted for further survival in wild conditions.
As a matter of interest, roughly 200 million North Sea plaice reach
marketable size (25 om) each year. About 75% of fish entering the
fishery are caught by trawlers, the British effort accounting for 25%
of the total take. In 1961, for instance, 35 million North Sea plaice
were caught by British vessels. If each fish be given a, hypothetical
allowance of 1 ft2 of bottom, then the annual British catch could be
housed in shallow ponds covering la square miles in extent.
Whereaa " reaping " the natural stock is the expensive aspect of
fishing, as we understand the term, " reaping " a pond stock is the
cheapest imaginable process-simply pull out the plug and drain the
pond. In this way, really fresh fish would become available to the
national market with minimum preservation and proceseing coste.
Prooessing plant is an expensive investment at the moment, inefficiently operated due to the fickle nature of fish supply. Rotational
pond cropping, in a systematic manner, would enable the industry
to trim its processing investment to the scale of continuous, guaranteed
Man has learned to domesticate and farm most of his important
food animals, with the notable exception of sea fish. It is this fundamental anomaly, aa well as the problem of stock depletion, which
fosters scientific interest in prospects for marine fish farming. One
tlspect of fish husbandry, namely the transplantation of young fish
from overpopulated nursery grounds to richer feeding are=, has
Supply.
75
then it might be possible to rear a plaice or sole to marketable size
in less than 2 years, compared with the usual 5.
The natural diet of the plaice includes small molluscs and marine
worms, Mussel (Nytilus edulis) culture on a large scale should present
no speoial difficulties ; it is not beyond the realms of possibility that a
oheap manufactured food based on fish offal or agricultural by-products,
with balanced additives, would be acceptable to marine fish in fattening
ponds.
Regarding those species most suitable for pond culture, flatfish, in
my opinion, give the best prospects of success-particularly the plaice,
sole, lemon sole and turbot. Flounders, witches and dabs enjoy a,
limited market. Our pelagic food-fish are more difficult to rear in tanka,
and one wonders whether the effort required would be covered by the
value of such fish on the market.
Stock selection for fast growth and other desirable market charmteristics would be most rewarding when the selected strain is destined
to complete its life in an artificial, protected environment. It may be a
muoh more difficult taak to select, from hatchery-rear- stock, those
strains best fitted for further survival in wild conditions.
As a matter of interest, roughly 200 million North Sea plaice reach
marketable size (25 om) each year. About 75% of fish entering the
fishery are caught by trawlers, the British effort accounting for 25%
of the total take. In 1961, for instance, 35 million North Sea plaice
were caught by British vessels. If each fish be given a, hypothetical
allowance of 1 ft2 of bottom, then the annual British catch could be
housed in shallow ponds covering la square miles in extent.
Whereaa " reaping " the natural stock is the expensive aspect of
fishing, as we understand the term, " reaping " a pond stock is the
cheapest imaginable process-simply pull out the plug and drain the
pond. In this way, really fresh fish would become available to the
national market with minimum preservation and proceseing coste.
Prooessing plant is an expensive investment at the moment, inefficiently operated due to the fickle nature of fish supply. Rotational
pond cropping, in a systematic manner, would enable the industry
to trim its processing investment to the scale of continuous, guaranteed
Man has learned to domesticate and farm most of his important
food animals, with the notable exception of sea fish. It is this fundamental anomaly, aa well as the problem of stock depletion, which
fosters scientific interest in prospects for marine fish farming. One
tlspect of fish husbandry, namely the transplantation of young fish
from overpopulated nursery grounds to richer feeding are=, has
Supply.