Taxonomic name: Kappaphycus spp.
Common names: agal agal, agal agal besar, agar agar besar, agar agar pulau, agar agar seru laut, agar-agar, algae, algues rouges (French), brown licorice, chilin-t' sai, cottonii, eucheuma, eucheuman, guso, kirinsai, red alga
Organism type: alga
Kappaphycus spp. are red algae species that have been introduced in various parts of the world for the purpose of harvesting the gelling agent kappa carrageenan, which is used in industrial gums and as a smoothening agent used in ice cream, toothpaste, jellies, medicines and paint. This species can regrow from fragments as small as 0.5cm making it an extremely difficult species to control.
Kappaphycus spp. is a tough, fleshy, firm; algae that can grow up to 2m tall. The thalli are coarse, with axes and branches 1-2cm in diameter and heavy major axes that are relatively straight, but lacking secondary branches near the apices. These algae frequently and irregularly branch with most branches both primary and secondary branches intercalated between primary branches. The algae is shiny green to yellow orange (University of Hawai‘i, UNDATED).
Kappaphycus alvarezii, Kappaphycus cottonii, Kappaphycus inermis, Kappaphycus interme, Kappaphycus procrusteanum, Kappaphycus striatum
coastland, marine habitats
Kappaphycus spp. can be found on reef flats and reef edges anywhere from 1 to 17m deep. It is often loosely attached to broken coral. Unattached fragments can be found floating in shallow and deep waters. This species can form large, moving mats of unattached fragments (University of Hawai‘i, UNDATED).
Kappaphycus spp. high growth rate, plastic morphology, and extremely successful vegetative regeneration makes them potentially destructive invasive species not just in Hawai‘i but around the globe (University of Hawai‘i, UNDATED). Conklin et al. (UNDATED) reports that Kappaphycus spp. is a serious danger to the coral reefs. Research has shown that Kappaphycus spp. have the ability to overgrow and kill coral. Woo et al. (1999) states that, "Observations have shown that the alga is able to coalesce into the tissue of the coral, providing a strong means for attachment, and thus allowing the alga to persist in high wave energy environments. The novel substrate and structure the algae provides may permit settlement of epiphytes previously absent, as well as shelter and protection for mesograzers." Woo (2001) documented fragments of Kappaphycus spp. weighing 0.05 g that were capable of net growth in the field, suggesting that fragments created by physical disturbance can be carried by waves and currents to new locations where they can possibly establish.
Granbom et al. (2004) states that, "The marine red alga Kappaphycus alvarezii is economically important due to the production of the gelling agent kappa carrageenan, which is used in industrial gums and other products." Tighe (1998) state that, "carrageen is a smoothening agent used in ice cream, toothpaste, jellies, medicines and paint."
Woo et al. (1999) state that, "Results from various studies so far suggest that a combination of several characteristics of the algae allow for its success as an invader: phenotypic plasticity that allows for persistence in high and low wave energy environments, asexual reproduction through fragmentation which may increase dispersal capabilities, physiological adaptations which permit coalescence and attachment to substrate, and possible chemical and morphological characteristics which lead to low grazer preference." "Once established in an area, Kappaphycus spp. alga may be able to spread laterally but, does not appear to be able to spread long distances or between islands" (Smith et al. 2002).
Native range: Philippines (Hurtado et al. 2001).
Known introduced range: K. alvarezii: Introduced into Fiji and Hawai‘ian Islands, Tahiti. Present in Indonesia, China. K. cottonii: Indonesia, Kenya, Tanzania, Saya de Malha Bank, Cargados Carajos, Tanzania, India, China, Japan, Vietnam, Malaysia, Guam, Fiji. K. inermis Tanzania. K. striatum India, Kenya, Tanzania, Madagascar, Japan, China, Singapore, Indonesia. Introduced in Fiji and Hawai‘ian Islands. (Guiry & Dhonncha, 2005).
Introduction pathways to new locations
Aquaculture: Granbom et al. (2004) states that, "The marine red alga K. alvarezii is economically important due to the production of the gelling agent kappa carrageenan, which is used in industrial gums and other products."
Local dispersal methods
Water currents: Woo (2001) documented fragments of Kappaphycus spp. weighing 0.05 g that were capable of net growth in the field, suggesting that fragments created by physical disturbance can be carried by waves and currents to new locations where they can possibly establish.
There are few studies in relation to the management and control of Kappaphycus spp. Most of the documented effort ongoing are into the study of the basic biology of the species. Some authors have begun researching possible biological control agents of this species, but there is very little information regarding control of this species.
In a study conducted by Conklin et al. (UNDATED), the authors demonstrated that, "1) Kappaphycus spp. will regrow in plots after mechanical harvest unless further action is taken, 2) increases in nutrient availability lead to increased rates of regrowth, and 3) the enhancement of herbivore densities dramatically decreased the rate at which regrowth occurrs. The results obtained with the urchins in the above experiment led to the addition of urchins to plots where K. alvarezii cover was approximately 60%. These plots showed that urchins in high densities could reduce invasive algal cover by almost 100% in 2-3 months."
The University of Hawai‘i (UNDATED) states that, "At the tip of each branch is a cluster of apical cells potentially high in regenerative capabilities that are able to regenerate a new thallus after breaking off. A broken tip can grow into full-sized thalli in a short period of time." Smith et al. (2002) report the results of their study that showed that "Kappaphycus spp. regrew in the field from fragments as small as 0.5cm. This method of reproduction is most likely the primary mode of propagation for Kappaphycus spp." They further observe that Kappaphycus spp. in Hawai‘i have only recently been observed to reproduce sexually.
The life cycle of Kappaphycus spp. are triphasic consisting of three independent life stagesthe carposporophyte (2N), tetrasporophyte (2N) and gametophyte (N) phases (Aska and Azanzab, 2002).
Reviewed by: Dr. Marit Ruge Bjaerke Section for Marine Biology and Limnology Department of Biology University of Oslo Norway
Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
Last Modified: Monday, 16 May 2005