California Seaweeds eFlora: Non-Native Seaweed Species List Glossary Index:
| A | B | C | D | E | F | G | H | I | K | L | M | N | O | P | R | S | T | U | V | W | X | Z |

Green Algae (Chlorophyceae)
 (Click on the specimen number in the text to see the herbarium specimen)

Bryopsis spp. (Silva 1979; Miller, Aguilar-Rosas & Pedroche 2011) Three weedy strains of Bryopsis were reported from San Francisco Bay by Silva, based on unpublished culture work by Dennis Shevlin. Their identity has not been determined. Their behavior, including explosive population growth, is that of introduced species.

Codium fragile (Suringar) Hariot (Brodie, Maggs & John 2007; Provan et al. 2008) This notoriously weedy strain has spread throughout the North Atlantic and has made its way into the Mediterranean and Pacific Ocean as far as Australia and New Zealand. Its arrival on the Pacific coast of North America was recorded by Silva (1979: 345, fig. 15), who reported it from San Francisco Bay. Subsequently, it has been found in Tomales Bay and at Newport, Oregon. Unlike the indigenous subspecies of C. fragile subsp. californicum, which is restricted to the outer coast, the non-native species grows in protected waters. There are no gross morphological characters by which the two subspecies may be distinguished.

Ulva clathratioides L. Kraft, G.T. Kraft, & R. Waller (Hughey 2013) Described from southern Australia. Floating, upper intertidal, Elkhorn Slough, 2012 (UC1997148-51).

Ulva australis Areschoug (Hughey 2013; Kirkendale et al. 2013) Native to Asia. In Baja California, Mexico, Orange and San Diego Cos., Tomales Bay, Marin Co., Elkhorn Slough and Monterey Harbor, Monterey Co. (UC1997152-8), 2011-12.


Brown Algae (Phaeophyceae)
 (Click on the specimen number in the text to see the herbarium specimen)

Ascophyllum nodosum (Linnaeus) LeJolis (Miller et al. 2004; Miller, Aguilar-Rosas & Pedroche 2011) Repeatedly introduced as packing material for east coast seafoods (e.g., lobsters). Small population in San Francisco Bay has been eradicated, but re-introduction is probable.

Colpomenia claytoniae S.M.Boo, K.M.Lee, G.Y.Cho & W.Nelson (Boo et al. 2011) Reported from Korea, Japan, Hong Kong, Australia, New Zealand, South Africa. In California, from Coral Street Beach, Monterey Co., 1999; San Pedro, Los Angeles Co. 2010, on rock.

Colpomenia peregrina Sauvageau (Lee et al. 2013) Probably native to Asia, but now widespread. Confirmed with molecular methods from Santa Catalina Island.

Elachista nigra Takamatsu (Kitayama, Miller, & Silva 2005) Native to Asia. Reported from San Clemente Island as an epiphyte on Eisenia arborea.

Fucus spiralis Linnaeus (Hughey et al. 1996; Serrao et al. 1999) Native to the Atlantic seaboards. Reported from Tomales Bay, but rare in California.

Mutimo cylindricus (Yendo) H. Kawai & T. Kitayama (nom. Inval). = Cutleria cylindrica Yendo (Stewart 1991; Kawai et al. 2012) Santa Catalina, San Clemente, Anacapa islands; La Jolla, San Diego County.

Padina durvillei Bory (unpublished) Reported from Marina Del Reye, Orange Co., 2016 (UC2050563).

Sargassum horneri (Turner) C. Agardh (Miller et al. 2007; Miller & Engle 2009) Native to Asia. Confirmed from Point Loma, San Diego Co., 2007 (UC1965307, UC1965309); Mission Bay, San Diego Co., 2013 (UC2019970-72); Long Beach Harbor, 2004 (UC1965143); Santa Catalina Island, 2006-7 (UC1965072-3, UC2019947), San Clemente Island, 2007 (UC1965079, UC2019938-42); Santa Cruz islands, 2011-12 (UC2019935, UC2019937); Anacapa Island.

Sargassum muticum (Yendo) Fensholt (Abbott & Hollenberg 1976; Miller, Aguilar-Rosas & Pedroche 2011) World-wide invasive, originally from Asia. Introduced to the west coast before World War II, it was detected in British Columbia, Canada in 1944, Oregon in 1947, Crescent City, California in 1963, Santa Catalina Island in southern California in 1970, and San Francisco Bay in 1973.

Undaria pinnatifida (Harvey) Suringar (Silva et al. 2002; Miller & Engle 2009) Native to Asia. In California, it was discovered in Los Angeles Harbor in 2000. It has since spread to Santa Barbara Harbor, Monterey Harbor, Santa Catalina Island, Mission Bay, San Diego, San Francisco Bay (2008) and Anacapa Island (2016).


Red Algae (Rhodophyceae)
 (Click on the specimen number in the text to see the herbarium specimen)

Agardiella subulata (C. Agardh) Kraft & Wynne (unpublished) Reported from Lake Merritt, Oakland, CA; R.L. Moe & J.R. Hughey (In UC).

Aglaothamnion tenuissimum (Bonnemaison) Feldmann-Mazoyer (Josselyn & West 1985; Miller, Aguilar-Rosas & Pedroche 2011) Reported as Callithamnion byssoides, attached to rocks throughout San Francisco Bay.

Antithamnion nipponicum Yamada et Inagaki (Cho, Won & Fredericq 2006; Rueness et al. 2007) Reported from San Francisco Bay as Antithamnion hubbsii. Confirmed from Half Moon Bay in 2003.

Asparagopsis armata Harvey (Ni Chualain et al. 2004; Miller, Aguilar-Rosas & Pedroche 2011) Native to Australia and New Zealand, was introduced into the Mediterranean Sea and Atlantic Ocean in the 1920s and is now a conspicuous invasive species in North Atlantic Europe. The minute filamentous diploid phase of this species was collected in 1972 in San Diego and identified by molecular analysis. This species has not been observed since the original collection.

Caulacanthus okamurae Yamada (Zuccarello, West & Rueness 2002; Miller, Aguilar-Rosas & Pedroche 2011) Probably native to Asia, though more research is required to determine the identity and origin of this species in California. Introduced to southern California, Santa Cruz, San Francisco Bay and Tomales Bay, Sonoma County. Spreading rapidly.

Ceramium kondoi Yendo (Cho, Boo & Hansen 2002; Miller, Aguilar-Rosas & Pedroche 2011) Native to Asia, but has also been collected in Alaska, Vancouver Island, Canada and Oregon. In 1999, a single specimen was collected at Bodega Bay, Sonoma Co. to Asia.

Ceramium sungminbooi J.R.Hughey & G.H.Boo (Hughey & Boo 2016) Native to Korea. Collected in Sausalito, San Francisco Bay, California (UC2050592); Hatfield and Coos Bay, Oregon.

Dasya sessilis Yamada (Hughey, Miller & Lyman 2009; Miller, Aguilar-Rosas & Pedroche 2011) Native to Asia. Attached to floating docks at Coronado Cays, Coronado Bay, San Diego, 2008-9; Huntington Harbor, Huntington Beach, Orange Co., attached to vertical faces of concrete pilings (UC1944739); attached to vertical sides of concrete pilings and wood on floating docks, Long Beach, Los Angeles Co., 1976, (UC1846061), 2006 (UC1944738).

Gelidium vagum Okamura (Hughey et al. 1996) Native to Asia. In California, confirmed from Tomales Bay, Sonoma County 1994-5 (UC1934317-18, UC1934320, UC1604005, UC1974628, UC1749968, UC1974542, UC1974629).

Gracilaria parvispora I.A. Abbott (unpublished) (Garcia-Rodriguez et al. 2013) Described from Oahu, Hawaii. Reported from Baja California, Mexico in 2013. Detected by DNA sequence in these California specimens: UC1863794, UC1965546, UC1863789, UC1863791, UC1863790; S. Krueger-Hadfield.

Gracilaria vermiculophylla (Ohmi) G.F. Papenfuss (Bellorin, Oliveira & Oliveira 2004; Hughey 2013) Identified first in Elkhorn Slough, Monterey Co.; now confirmed from Tomales Bay, Estero Americano Marin Co), Moss Landing Harbor, Monterey Co. and Santa Crz, Santa Cruz Co. (UC2018521, UC1514455, UC1514457, UC93924).

Gracilariopsis chorda (Holmes) Ohmi (Hughey 2013; Hughey 2015) Native to Japan, Korea and China. In California, attached to a concrete boat ramp in Kirby Park, Elkhorn Slough, Monterey County, 2011-2012 (UC1997139-46); attached to small pebbles buried in sandy mud in the lower intertidal on a sandspit in Morro Bay, San Luis Obispo Co., 2013 (UC1965346, UC1965347).

Grateloupia asiatica S. Kawaguchi & H.W. Wang (Hughey 2013) Native to Japan, Korea and China. In California, on dock below the Coronado Boathouse Restaurant, Coronado Island, San Diego, 2012 (UC1997160). Also collected in the Estero Americano, Marin Co., R.L. Moe, 2015 (in UC).

Grateloupia turuturu Yamada (Hughey, Miller & Lyman 2009; Miller, Aguilar-Rosas & Pedroche 2011) World-wide invasive, originally from Asia. Confirmed from Mission Bay, San Diego Co., 2011 (UC2036039-40); Alamitos Bay, Los Angeles Co., 2013 (UC1966771); Oxnard, San Luis Obisbo Co., 2013 (UC2050491, UC2050490); Santa Barbara Harbor, 2009 (UC1944749-50); Morro Bay, San Luis Obisbo Co., 2016 (UC2050489).

Lomentaria hakodatensis Yendo (Abbott & Hollenberg 1976) Native to Asia. Introduction date unknown; southern, central and northern California.

Neosiphonia harveyi (J.W. Bailey) M.-S. Kim, H.-G. Choi, Guiry, & G.W. Saunders (Choi, Kim, Guiry & Saunders 2001; McIvor et al. 2001) Native to Japan. First reported from southern California as Polysiphonia acuminata. Identified with DNA sequences from Monterey Bay; also attached to the underside of floating wood docks and on the vertical sides of concrete pilings 0-6 m in depth, Humboldt Bay, Humboldt Co., 2006, (UC 1944754). Collected at Estero Americano, Marin Co., 2013 (UC1965163, UC1965147), and Emeryville Marina, San Francisco Bay (UC2050549).

Pachymeniopsis lanceolata (Okamura) Yamada ex S. Kawabata (Hughey & Miller 2009; Miller, Aguilar-Rosas & Pedroche 2011) Native to Japan. Confirmed from Coronado Cays, Coronado Bay, San Diego Co., 2008-9 (UC1944742-44); Santa Cattalina Island, Los Angeles Co. , 2003, 2008 (UC1934301, UC1934303); (Port Hueneme, Ventura Co., 2006 (UC1944741); Moss Landing, Monterey Co., 2008 (UC1934301-13); San Francisco Marina, San Francisco Co., 2009 (UC1944746-8).

Polysiphonia denudata (Dillwyn) Greville in W. Hooker (Josselyn & West 1985) First reported in 1985; Coyote Point, San Francisco Bay, San Mateo Co. (UC1876501, UC1876506, UC1876487) and Richmond Marina, Contra Costa Co. (UC1617909).

Pyropia suborbiculata (Kjellman) J.E. Sutherland, H.G. Choi, M.S. Hwang & W.A. Nelson (Hughey 2011; Sutherland et al. 2011) Native to Asia. In California, upper intertidal, Nick's Cove, Tomales Bay, Marin Co., 2011 (UC1966687-9).

Schizymenia dubyi (Chauvin ex Duby) J. Agardh (Hughey & Miller 2009) Reported from Europe, Africa, Asia, New Zealand, and Australia. In California, attached to floating docks, Monterey Marina, Monterey Harbor, Monterey Co., 2006-8,(UC1934344, UC1934345, UC1934346, UC1934347).


Abbott, I.A. and Hollenberg, G.J. 1976. Marine Algae of California. Pp. 1-827. Stanford University Press.

Bellorin, A.M., Oliveira, M.C. & Oliveira, E.C. 2004. Gracilaria vermiculophylla: A western Pacific species of Gracilariaceae (Rhodophyta) first recorded from the eastern Pacific. Phycological Research 52: 69-79.

Boo, S.M., Lee, K.M., Cho, G.Y. & Nelson, W.A. 2011. Colpomenia claytonii sp. nov. (Scytosiphonaceae, Phaeophyceae) based on morphology and mitochondrial cox 3 sequences. Botanica Marina 54: 159-167.

Brodie, J., Maggs, C.A. & John, D.M. 2007. Green seaweeds of Britain and Ireland. Pp. 1-242, 101 figs., London: British Phycological Society.

Cho, T.O., Boo, S.M. & Hansen, G.I. 2002. Structure and reproduction of the genus Ceramium (Ceramiales, Rhodophyta) from Oregon, USA. Phycologia 40: 547-571.

Cho, T.O., Won, B.Y. & Fredericq, S. 2006. Antithamnion nipponicum (Ceramiaceae, Rhodophyta), incorrectly known as A. pectinatum in western Europe, is a recent introduction along the North Carolina and Pacific coasts of North America. European Journal of Phycology 40: 323-335.

Choi, H.-G., Kim, M.S., Guiry, M.D. & Saunders, G.W. 2001. Phylogenetic relationships of Polysiphonia (Rhodomelaceae, Rhodophyta) and its relatives based on anatomical and nuclear small-subunit rDNA sequence data. Canadian Journal of Botany 79: 1465-1476.

Hughey, J.R. 2013. Noteworthy collections. California. Madroño 60: 57-59.

Hughey, J.R. 2015. Noteworthy Collections. Madroño 62: 73-74.

Hughey, J.R. & Boo, G.H. 2016. Genomic and phylogenetic analysis of Ceramium cimbricum (Ceramiales, Rhodophyta) from the Atlantic and Pacific Oceans supports the naming of a new invasive Pacific entity Ceramium sungminbooi sp. nov. Botanica Marina 15(4): 211-222.

Hughey, J.R., Kieldsen, C.K., Silva, P.C., Moe, R.L. & DeCew, T.C. 1996. Noteworthy collections. California. Madroño 43: 432.

Hughey, J.R. & Miller, K.A. 2009. Noteworthy collection. Madroño 56: 64.

Hughey, J.R., Miller, K.A. & Lyman, A. 2009. Noteworthy collection. Madroño 56: 293-295.

Josselyn, M.N. & West, J.A. 1985. The distribution and temporal dynamics of the estuarine macroalgal community of San Francisco Bay. Hydrobiologia 129: 139-152.

Kawai, H., Kogishi, K., Hanyuda, T. & Kitayama, T. 2012. Taxonomic revision of the genus Cutleria proposing a new genus Mutimo to accommodate M. cylindricus (Cutleriaceae, Phaeophyceae). Phycological Research 60: 241-248.

Kirkendale, L., Saunders, G.W. & Winberg, P. 2013. A molecular survey of Ulva (Chlorophyta) in temperate Australia reveals enhanced levels of cosmopolitanism. Journal of Phycology 49(1): 69-81.

Kitayama, T., Miller, K.A. & Silva, P.C. 2005. First record of Elachista nigra (Chordariales, Phaeophyceae) from California, North America. Bulletin of the National Science Museum, Tokyo, Ser. B, 31: 57-61.

Lee, K.M., Boo, G.H., Coyer, J.A., Nelson, W.A., Miller, K.A., and Boo, S.M. 2013. Distribution patterns and introduction pathways of the cosmopolitan brown alga Colpomenia peregrina using mt cox3 and atp6 sequences. Journal of Applied Phycology 26: 491-504.

Miller, K.A. & Engle, J.M. 2009. The natural history of Undaria pinnatifida and Sargassum filicinum at the California Channel Islands: Non-native seaweeds with different invasion styles. Pp 131-140 in Damian, C.C. and D.K. Garcelon (eds.). 2009. Proceedings of 131 the 7th California Islands Symposium. Institute for Wildlife Studies, Arcata, CA.

Miller, K.A., Aguilar-Rosas, L.E. & Pedroche, F.F. 2011. A review of non-native seaweeds from California, USA and Baja California, Mexico. Hidrobiologica 21:240-254.

Miller, A.W., Chang, A.L., Consentino-Manning, N. & Ruiz, G.M. 2004. A new record and eradication of the Northern Atlantic alga Ascophyllum nodosum (Phaeophyceae) from San Francisco Bay, California, USA. Journal of Phycology 40: 1028-1031.

Ní Chualáin, F., Maggs, C.A., Saunders, G.W. & Guiry, M.D. 2004. The invasive genus Asparagopsis (Bonnemaisoniaceae, Rhodophyta): molecular systematics, morphology, and ecophysiology of Falkenbergia isolates. Journal of Phycology 40: 1112-1126.

Rueness, J., Heggøy, E., Husa, V. & Sjøtun, K. 2007. First report of the Japanese red alga Antithamnion nipponicum (Ceramiales, Rhodophyta) in Norway, an invasive species new to northern Europe. Aquatic Invasions 2(4): 431-434.

Serrão, E.A., Alice, L.A. & Brawley, S.H. 1999. Evolution of the Fucaceae (Phaeophyceae) inferred from nrDNA-ITS. Journal of Phycology 35: 382-394.

Silva, P.C. 1979. The benthic algal flora of central San Francisco Bay. In: San Francisco Bay: the Urbanized Estuary. (Conomos, T.J., ed.), pp. 287-345. San Francisco: Pacific Division, American Association for the Advancement of Science.

Silva, P.C., Woodfield, R.A., Cohen, A.N., Harris, L.H. & Goddard, J.H.R. 2002. First report of the Asian kelp Undaria pinnatifida in the northeastern Pacific Ocean. Biological Invasions 4: 333-338.

Stewart, J.G. 1991. Marine algae and seagrasses of San Diego County. California Sea Grant College, University of California, La Jolla, Calif. Report No. T-CSGCP-020. Pp. 197.

Sutherland, J.E., Lindstrom, S.C., Nelson, W.A., Brodie, J., Lynch, M.D.J., Hwang, M.S., Choi, H.-G., Miyata, M., Kikuchi, N., Oliveira, M.C., Farr, T., Neefus, C.D., Mols-Mortensen, A., Milstein, D., Müaut;ller, K.M. 2011. A new look at an ancient order: generic revision of the Bangiales (Rhodophyta). Journal of Phycology 47: 1131-1151.

Zuccarello, G.C., West, J.A. & Rueness, J. 2002. Phylogeography of the cosmopolitan red alga Caulacanthus ustulatus (Caulacanthaceae, Gigartinales). Phycological Research 50: 163-172.