BIOLOQY O F SEAWEEDS OB EaONOWC IMPORTANCE
131
production of alginic acid ; considerable quantities of intertidal fucoid
algae were also collected. About 4 400 tons fresh weight of Chondrus
and Gigartim were harvested. The increased utilization of red algae
in Spain was shown by data for the annual output of agar (Fig. 4)
(Aravio-Torre, 1952). Brown algae have also been collected for alginic
acid (Val and Pineda, 1949).
Records of kelp production for the California coast over the years
1940
8,000
6,000
4.000
2,000
4,000
1
r 2,000
1942
I
I
I
I
,
I
l
I
l
a,
.=
uI 6,000
4,000
2.000
1944
6,000
4,000
2,000
Jan. Feb Morch April May June July dug. Sep?. Ocf. Nov. Dec
FIG. 5. Kelp production from California for the years 1940-1945. Drawn from data in
Tseng (1947).
1940-1945 have been given by Tseng (1947), and are summarized in
Fig. 5. There are general indications that the greater quantities are
harvested during the summer months, but there is a good deal of variation from year to year. The mean annual harvests for 1940-1945 were
about one tenth of those obtained during 1917 and 1918. For the
Atlantic coast, Tseng estimated that 4 000 tons fresh weight of kelp
(mainly Laminaria sp.) were harvested in 1944. Estimates of Gelidium
production in California and Baja California, Mexico, indicated that
in southern California some 240 tons wet weight of Cfelidium were