BIOLOGY OF SEAWEEDS OF ECONOMIC IMPORTANCE
133
harvested in 1944, whilst the quantities collected at Baja, California,
were ten times this amount (Tseng, 1947). On the east coast, Clrracilaria
has been obtained in quantities of 1 500 tons fresh weight in 5 months
of collecting at Beaufort, North Carolina. From information on standing
crops it seems likely that there is still considerable scope for development.
Data on seaweed utilization in Japan are summarized in Table IX.
In addition to the information listed in the Table, Kurogi (1963a)
reports that a further 63 000 tons fresh weight of seaweed waa used
annually between 1955 and 1960. The figure of 78 000 tons fresh weight
of Porphyra harvested annually is equivalent to 2 117 537 800 " sheets "
of dried laver weed sold for human consumption. This contrasts with
the 213 tons of Porphyra sold in South Wales during 1954 (Hampson,
1957). Scagel states that the Japanese " Porphyra " industry employs
some 300000 individuals, and that the areas under cultivation in
Tokyo Bay approximated some 10 000 acres (Scagel, 1961). Allowing
for the annual turnover in the Japanese industry, it is interesting to
see reports that Gracilaria v e r r w s a is being imported from Africa for
the extractives contained (Tagawa, Takeyama and Kojima, 1961).
V. LIFE HISTORIES AND SEASONAL ECOLOQY OF THE SEAWEEDS OF
ECONOMIC IMPORTANCE
There have been a number of reviews in recent years on the ways
of classifying the different life histories seen in the algae and on the
nomenclature to be used (Drew, 1955 ; Chapman and Chapman, 1961 ;
Dixon, 1963a,b). Since a relatively small number of algae are under
discussion here it is not proposed to deal any further with this point,
and in any case a good deal of confusion surrounds the basic features
of such a classification at the present time. Some of the more recent
work on the various genera will be separately considered.
A. Chlorophyceae
Three genera of algae are principally concerned, Monostrow,
Enteromorphu and Ulva. Their main use is as food, but two of the
genera, Enteronzorphu and Ulva, are of further economic significance
because they are mainly responsible for ship-fouling. This last topic
warrants a separate review, and will not be dealt with in detail here.
Monostroma plants are utilized as food in Japan, and are cultivated
on " hibi "* in specific areas of the shallow seas. The origin of Monostroma cultivation appears to lie in the plants growing as contaminants
on the Porphyra " hibi " (p. 165). Certain areas of the culture grounds
* Arti6cial substrete for cultivation, see page 165.
133
harvested in 1944, whilst the quantities collected at Baja, California,
were ten times this amount (Tseng, 1947). On the east coast, Clrracilaria
has been obtained in quantities of 1 500 tons fresh weight in 5 months
of collecting at Beaufort, North Carolina. From information on standing
crops it seems likely that there is still considerable scope for development.
Data on seaweed utilization in Japan are summarized in Table IX.
In addition to the information listed in the Table, Kurogi (1963a)
reports that a further 63 000 tons fresh weight of seaweed waa used
annually between 1955 and 1960. The figure of 78 000 tons fresh weight
of Porphyra harvested annually is equivalent to 2 117 537 800 " sheets "
of dried laver weed sold for human consumption. This contrasts with
the 213 tons of Porphyra sold in South Wales during 1954 (Hampson,
1957). Scagel states that the Japanese " Porphyra " industry employs
some 300000 individuals, and that the areas under cultivation in
Tokyo Bay approximated some 10 000 acres (Scagel, 1961). Allowing
for the annual turnover in the Japanese industry, it is interesting to
see reports that Gracilaria v e r r w s a is being imported from Africa for
the extractives contained (Tagawa, Takeyama and Kojima, 1961).
V. LIFE HISTORIES AND SEASONAL ECOLOQY OF THE SEAWEEDS OF
ECONOMIC IMPORTANCE
There have been a number of reviews in recent years on the ways
of classifying the different life histories seen in the algae and on the
nomenclature to be used (Drew, 1955 ; Chapman and Chapman, 1961 ;
Dixon, 1963a,b). Since a relatively small number of algae are under
discussion here it is not proposed to deal any further with this point,
and in any case a good deal of confusion surrounds the basic features
of such a classification at the present time. Some of the more recent
work on the various genera will be separately considered.
A. Chlorophyceae
Three genera of algae are principally concerned, Monostrow,
Enteromorphu and Ulva. Their main use is as food, but two of the
genera, Enteronzorphu and Ulva, are of further economic significance
because they are mainly responsible for ship-fouling. This last topic
warrants a separate review, and will not be dealt with in detail here.
Monostroma plants are utilized as food in Japan, and are cultivated
on " hibi "* in specific areas of the shallow seas. The origin of Monostroma cultivation appears to lie in the plants growing as contaminants
on the Porphyra " hibi " (p. 165). Certain areas of the culture grounds
* Arti6cial substrete for cultivation, see page 165.