Smothering Seaweed
Smothering Seaweed (Kappaphycus alvarezii and Eucheuma spp.)
Photo courtesy of DAR
Eucheuma spp.
Description:
- Thick intertwined branches that form mats (CABI, 2019)
- Branches are cylindrical axes with spines (CABI, 2019)
Habitat:
- Typical found in shallow, subtidal reef flats (Russell, 1983)
Impacts & Concern:
- High growth rate and reproduces through fragmentation (Russell, 1983)
- Shades out and smothers corals (Russell, 1983)
Introduction:
- Introduced from the Philippines to Kāne‘ohe Bay in 1974 for scientific experiments (Russell, 1983)
Distribution in Hawaii:
Reported distribution of Eucheuma sp. and Kappaphycus sp. in the Main Hawaiian Islands
- Kauai: Not documented
- O‘ahu: Present in Kāne‘ohe Bay (CABI, 2019)
- Molokai: Not documented
- Lanai: Not documented
- Maui: Not documented
- Big Island: Not documented
Related AIS Team Management Projects:
- Urchin outplanting efforts in Kāne‘ohe Bay
References:
- CABI. (2019). Eucheuma Spp. [Data sheet]. https://www.cabi.org/isc/datasheet/102037
- Russell, D. (1983). Ecology of the Imported Red Seaweed Eucheuma striatum Schmitz on Coconut Island, Oahu, Hawaii. Pacific Science, 37(2), 87-107. https://core.ac.uk/download/pdf/5093462.pdf
Kappaphycus alvarezii
Photo courtesy of DAR
Description:
- Coarse branches in irregular patterns (UH Mānoa, 2001)
- Shiny green to orange-yellow in color (UH Mānoa, 2001)
- Intertwined branches to form thick mats (UH Mānoa, 2001)
Habitat:
- Typically found on patch reefs in shallow water (Rodgers & Cox, 1999)
- Inhabits sand-covered grooves in reef (Rodgers & Cox, 1999)
Impacts & Concern:
- High growth rate and vegetative regeneration makes it quick to spread (UH Mānoa, 2001)
- Can double in size in 15-30 days (UH Mānoa, 2001)
- Shadows and smothers native corals (UH Mānoa, 2001)
Introduction:
- Introduced to Kāne‘ohe Bay for commercial cultivation in 1974 (Rodgers & Cox, 1999)
Distribution in Hawaii:
- Kauai: Not documented
- Oʻahu: Present in Kāne‘ohe Bay (Rodgers & Cox, 1999)
- Molokai: Not documented
- Lanai: Not documented
- Maui: Not documented
- Big Island: Not documented
References:
- UH Mānoa. (2001). Kappaphycus alvarezii Fact Sheet. https://www.hawaii.edu/reefalgae/invasive_algae/pdf%20files/kappaphycus_alvarezii.pdf
- Rogers, S.K. & Cox, E.F. (1999). Rate of spread of introduced rhodophytes Kappaphycus alvarezii, Kappaphycus striatum, and Gracilaria salicornia and their current distributions in Kane’ohe Bay, O’ahu, Hawai’i. Pac Sci, 53(3), 232-241.
