A preliminary comparison of the mariculture potential of Porphyra purpurea and Porphyra umbilicalis

Due to their rapid growth and nutrient assimilation,Porphyra spp. are good candidates for bioremediation and polyculture. The production potential of two strains of P. purpurea and P. umbilicalis from north-east USA was evaluated by measuring rates of photosynthesis (as O₂evolution) of material grown at 20 ^°C. Photosynthetic rates of P. umbilicalis were 80%higher than P. purpurea over the temperature range 5–20 ^°C, at both sub-saturating andsaturating irradiances (37 and 289 μmol photonm^-2 s^-1). Porphyra umbilicalis was more efficient at low irradiances (higher α) and had a higher P_max (23.0 vs 15.6 μmolO₂ g^-1 DW min^-1) than P.purpurea, suggesting that P. umbilicalis is a better choice for mass culture, where self-shading maybe severe. This revised version was published online in August 2006 with corrections to the Cover Date.