Bureaucrat, administrator, widgeteditor
146,870
edits
Changes
→Production
Access and abundance of seaweed resources are two critical factors determining their commercial viability. Other factors determining viability include the costs of cultivation and harvesting (labour and/or equipment), drying, transportation, chemicals, water supply and environmental measures (McHugh, 1991).
The following taxa of seaweeds were cultivated in South-East Asia around 1973 (FAO, 1974): ''Caulerpa racemosa '' (Forsk.) J. Agardh, ''Chaetomorpha antennina '' (Bory) Kütz., ''C. crassa '' (C. Agardh) Kütz., ''Cladophora '' spp., ''Enteromorpha compressa '' (L.) Nees, ''Eucheuma edule '' J. Agardh (probably partly ''Betaphycus gelatinus '' and partly ''E. serra '' (J. Agardh) J. Agardh), ''E. denticulatum '' (Burm.f.) Collins & Herv. (as ''E. spinosum '' J. Agardh).
Other seaweeds have been added recently as cultivated organisms: ''Caulerpa lentillifera '' J. Agardh (this is probably the correct identification of most cultivated ''Caulerpa racemosa''), ''Enteromorpha clathrata '' (Roth) Grev., ''E. intestinalis '' (L.) Nees, ''Gracilaria '' spp., ''Kappaphycus alvarezii '' (Doty) Doty ex P.C. Silva, ''K. striatus '' (F. Schmitz) Doty ex P.C. Silva.
Until 1995 the Food and Agriculture Organization (FAO) published data on world production of all seaweeds together, thus no separation was made between data from phycoculture and from catches from natural populations. More recently these separate data have become readily available (Tables 2 and 3).
Usually FAO Fishery Statistics give seaweed quantities in metric t (wet weight). For industrial use, however, statistics are usually expressed in "dry weight". This is the mass of the seaweeds after it has been dried by natural means. These dried seaweeds usually contain about 20% moisture, but in Eucheuma and Kappaphycus, the main sources of carrageenan, buyers prefer 35% moisture for shipping convenience (McHugh, 1990). The fresh weight of seaweeds consists of 75-90% water. Of the remaining "true" dry weight, about 75% is organic matter and 25% mineral ash, consisting mainly of K, Na, Mg and Ca ions (Lüning, 1993). A conversion of dry weight versus wet weight is often necessary. Red algae especially shrink considerably during drying. The prices of dried and baled red seaweeds (in dry metric t) are thus distinctly higher than those for the fresh and wet product. The global prices for red algae are mainly influenced by the high prices and large amounts of Porphyra spp. produced in East Asia, while the high price for "miscellaneous aquatic plants" can not be explained on the basis of the available data.
<center>'''Table 2. World production of seaweeds by phycoculture (t wet weight).'''</center>
{| class="wikitable"
!Production
|-
!1986
!1990-1992
!1993-1995
!1996
!1997
|-
World
|-
| seaweeds total||3 400 089||4 599 520||6 789 656||7 166 780||7 241 449
|-
| Phaeophyta||2 269 880||3 230 676||4 541 362||4 909 269||4 978 402
|-
| Rhodophyta||888 246||1 109 761||1 571 875||1 750 505||1 758 348
|-
| Chlorophyta||21 476||33 514||29 695||28 479||32 989
|-
| miscellaneous||221 154||314 981||647 047||478 903||472 015
|-
| freshwater Chlorophyta||667||332||317||376||305
|-
| freshwater miscellaneous||0 ||11 ||5 ||0 ||0
|-
|Indonesia
|-
| Rhodophyta ||77 462||95 000<sup>1</sup>||104 333||148 000||157 000
|-
|The Philippines
|-
| total
|-
| "''Eucheuma alvarezii''"
|-
| "''Eucheuma cottonii''"
|-
| "''Eucheuma spinosum''"
|-
| ''Gracilaria''
|-
| Chlorophyta (''Caulerpa'')
168 868
4 627
145 632
8 173
0
10 436
307 4961
9 244
265 013
15 408
0
18 4901
480 438
10 426
434 933
13 472
4
21 606
631 387
12 903
590 107
8 551
0
19 826
627 105
4 533
589 263
8 149
0
24 890
Vietnam
Gracilaria
1 700
3 3331
6 5001
8 5001
12 000<sup>1</sup>
|}
1 FAO estimate.
Sources: FAO, 1996, 1999c.
==== Economic value ====