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Porphyra thallus and its holdfast (copy from MBARA in internet) |
Conchocelis filaments breeding facilities |
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Manually harvesting |
Harvesting with special machine |
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Porphyra processing |
Sushi in different cuisine |
In China, Porphyra haitanensis is found in southern areas, whereas P. yezoensis is found in the north. The life stage that is commonly called nori or laver, comprises the thalli of the species (see n.1 in figure shown below), which emerge in autumn or earlier winter along rocky coasts. Its seeds are called conchospores and are released from the filamentous conchocelis stage (see n. 8 in same figure), which are found settled on mollusc shells in the summer and autumn. Before 1949, the filamentous phase was thought to be a separate species, Conchocelis rosea.
Life cycle diagram of Porphyra spp. - A = Porphyra yezoensis; B = Porphyra haitanensis. 1 thallus; 2 spermagonium; 3 sperm; 4 carpogone; 5 fertilized egg; 6 carposporangium; 7 carpospore; 8 filamental conchocelis; 9 sporangium branch of conchocelis; 10 releasing conchospores; 11 conchospore; 12 young thallus; 13 monospore and young thallus |
DISEASE | AGENT | TYPE | SYNDROME | MEASURES |
Chytridiosis | Olpidiopsis sp. | Fungus | Mould spoilage; poor quality products; reduced production | Decreasing density of culture nets; improving management in the early stages |
Red rot disease | Pythium sp. | Fungus | Mould spoilage; poor quality products; reduced production | Drying culture nets; decreasing temperature |
Filamental disease | Leucothrix mucor | Bacterium | No information | Drying culture nets |
Atrophy | Unknown | Unknown | Diseased thalli are agaric (appear like fungi) and dark in colour | None known |
Pore disease | Unknown | Gram-negative bacterium. | Pathogen absorbs the nutrients of the thalli, causing holes to appear | Reduced salinity under laboratory conditions; no field measures |
Green rot disease | Pseudomonas sp. | Gram-negative bacterium | Spoilage | Drying culture nets; reduce planting density |
Discolouration diseases | Environmental stress | Thalli change from purple to yellow-green and then to white | Reduce stocking density |
Chen, G.Y. 1980. Study on Breeding of free-conchocelis filament of Porphyra haitanensis and its seeding. Journal of Fisheries of China, 4(1):19-30. |
Drew K.M. 1949. Conchocelis phase in the life history of Porphyra umbilicali (L) Kutz. Nature,164:748-751. |
Jia, J. & Chen, J. 2001. Sea Farming and Sea Ranching in China. FAO Fisheries Technical Paper No. 418. FAO, Rome, Italy. 71 pp. |
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Tseng, C.K. & Zhang, D.R. 1954. Study on Porphyra I: Life cycle of Porphyra tenera. ACTA BOTANICA SINICA. 3(1):287-302. |
Tseng, C.K. & Zhang, D.R. 1955. Study on Porphyra II: Filament stage of Porphyra tenera and its Conchospores. ACTA BOTANICA SINICA. 4(1):27-46. |
Tseng, C.K.,Wang, S.J., Liu, S.J., Guo, X.K., Zhang X.C. and Miao G.R. 1978. Phycoculture. Shanghai Science & Technique Press, Shanghai, China. Editor: Tseng C.K, Pp. 135-211. |
Tseng, C.K., Wu, C.Y., Fei, X.G., Zhang X.C., Qin, S. and Zhou, H.E. 1999. Biology on Economic Seaweed Seeds. In Biological Basics on Porphyra Seed. Shandong Science & Technique Press, pp. 154. Shanghai, China. Editor: Tseng C.K, pp. 50-90. |
Tseng, C.K., & Borowitzka, M. 2003. Algae culture. In J.S. Lucas & P.C. Southgate (eds.), Aquaculture: Farming Aquatic Animals and Plants, pp. 253-275. Blackwell Publishing, Oxford, England. |