212
A. D. BONBY
with this have been carried out (Gardner and Mitchell, 1966), and
there are many reports on the techniques of seaweed drying carried out
on both a large and small scale, e.g. Tseng (1947) on Gracihria, Cribb
(1964) on Nacrocystis, Marshall et al. (1949) on Gigartina and Chondrus,
and Newton (1963) on Chondrus drying in Nova Scotia. With agarophytes the product can be appreciably affected by the initial drying
processes.
*
Direct observations on sublittoral seaweed populations by divers
using self-contained breathing apparatus have been reported in earlier
pages, and the part such techniques can play in cultivation and harvesting of seaweed crops offers considerable scope. Studies on sublittoral populations have been successfully pursued by the use of
remote-controlled still cameras (Vevers, 1961) and with underwater
television (Barnes, 1963). The effects of weeding unwanted algae from
beds of harvestable weeds appear not to have been described in detail,
but preliminary work in this direction has been reported. Thus
“ farming ” the seabed is a reasonable probability.
VIII. WEEDINU
A number of reports are available on the effects of “weeding”
unwanted algae from the are= in which harvestable seaweeds are
growing. In some cases these methods have not been too successful.
Thus where regions of the shore bearing stands of C h d r w and Gigartina have been cleared of other algal growths from the neighbouring
rock in order to encourage the spread of the two species, the fucoid
algae and other species tend to come back in quantity. Only in the
instance of Chondrw was there any noticeable recolonization (Marshall
et al. 1949). When the shore in the vicinity of Ascophyllum is cleared
other fucoid algae subsequently predominate (p. 223). The Chondrw
beds in Nova Scotia may suffer from an overgrowth of the filamentous
green alga Chaetmrpha, and this can cause devaluation of the crop ;
too severe a harvesting of the Chondrw beds can.result in their replacement by Laminaria plants. Similarly, where large areas of Chondrus
are destroyed by unfavourable weather conditions the plants are often
replaced by Chordaria jlagellifmnis, and several years may elapse
before the Chondrus stocks are again built up (MacFarlane, 1962).
Chapman (1960) has described how beds of Laminaria japonica in
Japan may be invaded by the marine angiosperm Phyllospadix, and
the Laminaria “ grounds ’’ subsequently require “ weeding ”.
In Japan coralline algae such as Amphiroa epMraea can be harmful
because of their growth on agar-producing algae. Ogata (1952, 1963)
studied the distribution of Amphiroa spores in the sea in relation to
A. D. BONBY
with this have been carried out (Gardner and Mitchell, 1966), and
there are many reports on the techniques of seaweed drying carried out
on both a large and small scale, e.g. Tseng (1947) on Gracihria, Cribb
(1964) on Nacrocystis, Marshall et al. (1949) on Gigartina and Chondrus,
and Newton (1963) on Chondrus drying in Nova Scotia. With agarophytes the product can be appreciably affected by the initial drying
processes.
*
Direct observations on sublittoral seaweed populations by divers
using self-contained breathing apparatus have been reported in earlier
pages, and the part such techniques can play in cultivation and harvesting of seaweed crops offers considerable scope. Studies on sublittoral populations have been successfully pursued by the use of
remote-controlled still cameras (Vevers, 1961) and with underwater
television (Barnes, 1963). The effects of weeding unwanted algae from
beds of harvestable weeds appear not to have been described in detail,
but preliminary work in this direction has been reported. Thus
“ farming ” the seabed is a reasonable probability.
VIII. WEEDINU
A number of reports are available on the effects of “weeding”
unwanted algae from the are= in which harvestable seaweeds are
growing. In some cases these methods have not been too successful.
Thus where regions of the shore bearing stands of C h d r w and Gigartina have been cleared of other algal growths from the neighbouring
rock in order to encourage the spread of the two species, the fucoid
algae and other species tend to come back in quantity. Only in the
instance of Chondrw was there any noticeable recolonization (Marshall
et al. 1949). When the shore in the vicinity of Ascophyllum is cleared
other fucoid algae subsequently predominate (p. 223). The Chondrw
beds in Nova Scotia may suffer from an overgrowth of the filamentous
green alga Chaetmrpha, and this can cause devaluation of the crop ;
too severe a harvesting of the Chondrw beds can.result in their replacement by Laminaria plants. Similarly, where large areas of Chondrus
are destroyed by unfavourable weather conditions the plants are often
replaced by Chordaria jlagellifmnis, and several years may elapse
before the Chondrus stocks are again built up (MacFarlane, 1962).
Chapman (1960) has described how beds of Laminaria japonica in
Japan may be invaded by the marine angiosperm Phyllospadix, and
the Laminaria “ grounds ’’ subsequently require “ weeding ”.
In Japan coralline algae such as Amphiroa epMraea can be harmful
because of their growth on agar-producing algae. Ogata (1952, 1963)
studied the distribution of Amphiroa spores in the sea in relation to