Geographical Distribution Of Agarophytes

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Geographical Distribution Of Agarophytes

The geographical distribution of agarophytes is very wide and is
shown in Figure 3. Main areas are located indicating the most important
classes and species. The size of the coloured areas relate to the extent
of the gathering area, not the quantity of seaweeds gathered.

There are areas in which different kinds of agarophytes are
gathered. This is the case in Chile, a country of exceptional resources
of algae. In 1984, 6 126 tons of dried Gracilaria were gathered
from its very long sea coast and exported to Japan, as well as another 5
500 tons that were used by the local industry. Simultaneously, in rocky
areas, sandwiched between sandy areas where Gracilaria grows, 304 tons of dried Gelidium were gathered and exported to Japan. In countries such as India and Sri Lanka, Gracilaria and Gelidiella grow together in areas relatively close to each other. Generally Gelidium resources are being exploited quite heavily and so are those of good quality Gracilaria. At present the utilization of Gelidiella is being developed.

It is difficult to evaluate the present collection of agarophytes
all over the world but since Japan has been, for a long time, the sole
importing country of these seaweeds (basically needed to maintain
production levels of the agar industry), Japanese statistics (Figure 4a)
are very valuable in giving a true view of the situation. Note that in
the Japanese statistics, Gelidium seaweeds are separated from other seaweeds. In 1984, Japan imported 678 tons of Gelidium seaweeds and 9 462 tons of “other agarophytes”, mainly Gracilaria and Gelidiella. However it seems that Gelidiella is included with Gelidium in some cases, probably because Gelidiella seaweeds have been called Gelidium rigidum
by some phycologists in spite of the fact that they are generally
considered to be of a different class. As far as agar manufacturers are
concerned, they are not Gelidium since the product obtained from then is completely different from the real Gelidium agar. The Gelidium lots assigned to the Philippines (3 tonnes) and to Indonesia (62 tonnes) are probably Gelidiella. Also Gelidium from Brazil is most probably Pterocladia which can be confused with Gelidium (no Gelidium is harvested in Brazil while some quantities of Pterocladia are).

INDUSTRIAL HARVESTING TECHNIQUES

Industrial harvesting techniques for agarophytes vary, depending on circumstances, but they can be classified as follows:

(1) gathering of seaweeds washed to the shore;

(2) gathering seaweeds by cutting or rooting them out from their beds;

(3) cultivation.

Agarophyte seaweeds distribution map

Agarophyte seaweeds imported by Japan 1984

COUNTRY
QUANTITY
Gelidium Seaweeds:
* North Korea 112 MT
* Taiwan 4 MT
* Philippines 3 MT
* Indonesia 62 MT
* Chile 303 MT
* Brazil 20 MT
* Madagascar 74 MT
* South Africa 100 MT
TOTAL 678 MT
Other Seaweeds:
* North Korea 47 MT
* South Korea 48 MT
* Taiwan 77 MT
* Vietnam 15 MT
* Thailand 3 MT
* Philippines 1,470 MT
* Indonesia 69 MT
* Sri Lanka 45 MT
* Chile 6,128 MT
* Brazil 607 MT
* Argentina 58 MT
* South Africa 895 MT
TOTAL 9,462 MT

Figure 4b Agar production in different countries indicating the seaweeds used

COUNTRY
YEAR
GELIDIUM
PTEROCHLADIA
OTHER SEAWEEDS
TOTAL
Japan
1984
568 MT
1,872 MT
2,440 MT
Spain
1984
890
890
Chile
1984
820
820
South Korea
1984
600
600
Morocco
1984
550
550
Portugal
1984
260
60
320
Taiwan
1984
25
250
275
Argentina
1983
197
197
Indonesia
1984
150
150
People’s Republic of China
1984
50
90
140
Mexico
1984
80
80
United States
1984
70
70
France
1984
65
65
Brazil
1983
60
60
New Zealand
1983
26
26
TOTALS
3,158
86
3,439
6,683

“Other Seaweeds” are practically all Gracilaria
Agar quantities include natural agar, industrial agar and bacteriological agar.
In countries such as India and Vietnam there exists a small agar production but their data are not available.

Gathering of seaweeds washed to the shore. In some countries these
seaweeds called “argazos”, “arribazon” or “beach wash”. These are dead
seaweeds that, after completing their biological cycle, are separated by
seasonal storms. They are gathered by hand or by mechanical means from
the coast or by compressed air ejectors from boats that gather the
seaweeds settled in cavities at depths of about 25 metres (“wells”). To
avoid fermentation, the seaweed should be gathered shortly after it has
separated from its holdfast.

Gathering seaweeds by cutting or rooting them out from their
beds. This work is done with rakes or grabs handled from boats or by
scuba divers who operate from boats using compressed air bottles or,
more frequently, a compressor on the boat connected to the diver by a
hose (“hookah”). Gelidium usually occurs on rocky beds, Gracilaria
on sandy ones. In general it is feasible to operate with divers in
depths between 3 and 20 metres. In Japan, for many years, the seaweeds
have been gathered by diving girls or “amas” who operte from floats and
dive using only their lungs. These techniques of cutting or rooting out
are used exclusively in some countries and are similar to the ones used
for carrageenanophytes such as Chondrus crispus and other Chondrus species (Irish Moss) or alginophytes such as Macrocystis or Laminaria, adapting the equipment in each case to the morphological characteristics of each seaweed class.

Cultivation. Nowadays the need for greater quantities of agarophytes has brought about the introduction of cultivation of Gracilaria
crops, along the lines used for carrageenophytes. However this
cultivation has had only limited success and there are some aspects to
be solved before it can be generally adopted. At the present time,
cultivation for industrial purposes is undertaken in the People’s
Republic of China, its Taiwan Province and it is now being initiated in
Chile (Ren, Wang and Chen, 1984; Ren and Chen, 1986; Cheuh and Chen,
1982; Yang, 1982; Pizarro and Barrales, 1986; Santelices and Ugarte,
1986).

 Source: FAO

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