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Ulva reticulata Forssk. |
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Description: Plants of irregular shape, forming tangled masses of blades from a few cm to several meters across. Pale to dark green in color. Young plants initially attached with a small holdfast, but most older plants detached and merely tangled on other algae, rocks or corals. Reproduction occuring in small patches in the middle of blades, during or after spore release, these patches falling out of the blade and leaving a small hole. These holes becoming larger and forming the characteristic pattern or holes in the blades. Blades 2 cells thick, cells taller than wide or of more equal dimension. Introduction and Origin: Native to Hawaii. Hawaiian Distribution: Midway, Kauai, Oahu, Molokai, Lanai, Maui, Hawaii. Habitat: Uncommon but locally abundant in shallow water near areas where groundwater enters the ocean. Mostly found in low intertidal to 2m deep as an epiphyte. Uncommon in deeper water, but a few dredge collections to 128 m (possible drift?). Environmental Effects: Not studied. May affect recruitment of other species by successfully competing for substrate. World Distribution: Malaysia, Indonesia; Hawaiian Is., Okinawa, Japan, Formosa, Philippines; Indian Ocean, Red Sea. Type locality: Red Sea (Saudi Arabia). Commercial Interests: None. Rate of Spread / Method: High growth rate. Dispersal by vegetative propagation, and motile, photosynthetic gametes and zoospores. Factors likely to influence Spread and Distribution: High nutrients availability, low salinity, moderate water movement. Decrease of grazers populations. Reasons for Success: High growth rate, high chances for successful settlement, due to motile, photosynthetic zoospores and gametes, able to rapidly colonize new areas (Beach et al, 1995). Anthropogenic sources of nutrients (fertilizers runoff, sewage), decrease in grazing pressure. Control Methods: None used. Reduction of nutrient enriched freshwater outflow into the coastal areas. References: |
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