Mutimo cylindricus

Invasion History

First Non-native North American Tidal Record: 1973
First Non-native West Coast Tidal Record: 1973
First Non-native East/Gulf Coast Tidal Record:

---

General Invasion History:

Mutimo cylindricus ranges from the Tsugaru Strait, northern Honshu, Japan, to the Philippines (Silva et al. 1987; Kogishi et al. 2010; Guiry and Guiry 2016). In 1973, it was found on rocks in shallow water on Santa Catalina Island, California. It now ranges from Anacapa Island, California (Miller et al. 2011) to the Islas Coronado, Baja California Norte (Aguilar Rosas 1994). The date of introduction is not known.

North American Invasion History:

Invasion History on the West Coast:

Mutimo cylindricus was first collected at Pebbly Beach, Avalon, on Santa Catalina Island, California on May 4, 1973 (Hollenburg 1978). It was subsequently found at San Clemente Island (1986-1987), Bird Rock at La Jolla (1986) and Point Loma, San Diego (1984-1987). It is reported to be absent in years with colder seawater temperatures (Stewart 1991). It was found in Mexico at Raul's Restaurant, about halfway between Tijuana and Ensenada, and in the Islas Coronados, off Tijuana in 1991 (Aguilar Rosas 1994). The date of introduction is not known and this seaweed could have been overlooked for some time. Hull fouling and ballast water are the most likely vectors.

---

Description

The conspicuous form of Mutimo cylindricus is the gametophyte which develops as long, string-like branches, dividing dichotomously from a discoid holdfast. The branches taper to threadlike apices, 100–200 µm in diameter. The branches bear clusters of fine filaments about 1 mm long and 12–20 µm in diameter. These clusters of filaments are sori (masses of spore-producing structures). When mature, they bear 1–6 cylindrical plurilocular structures, 40–80 µm long. The overall length of the thallus is up to 230 mm. The thalli are greenish-to reddish brown in color. This description is based on: Hollenberg 1978, Stewart 1991, Aguilar-Rosas 1994, and Guiry and Guiry 2016.

Seaweeds of the genus Mutimo have a heteromorphic life-cycle, alternating between the conspicuous haploid gametophyte, and a small, crustose diploid sporophyte, formerly placed in a separate genus (Aglaozonia) (Bold and Wynne 1978). This life cycle is seen in most Japanese populations of M. cylindricus which reproduce sexually. In populations from Tsugaru Strait, northern Japan, and in plants from Santa Catalina Island, California, the gametophytes are all female and reproduce parthenogenetically. The sporophytes are absent (Kogisihi et al. 2010).

---

Taxonomy

Ecology

General:

Seaweeds of the genus Mutimo have a heteromorphic life-cycle, alternating between the conspicuous haploid gametophyte, and a small, crustose diploid sporophyte, formerly placed in a separate genus (Aglaozonia) (Bold and Wynne 1978). This life cycle is seen in most Japanese populations of M. cylindricus which reproduce sexually. In populations from Tsugaru Strait, northern Japan, and in plants from Santa Catalina Island, California, the gametophytes are all female and reproduce parthenogetically. The sporophytes are absent (Kogisihi et al. 2010).

Mutimo cylindricus has a wide native range, from northern Japan to the Philippines, from cold-temperate to warm-temperate climates (Silva et al. 1987; Kogishi et al. 2010). In southern California, information on M. cylindricus's temperature responses appears to be contradictory. Stewart (1991) associates it with periods of warm seawater (El Nino), being absent in cold-water periods. However, recent work suggests it is a winter-spring annual, growing in cooler times of year (Miller et al. 2011). Available records from Japan and California come from rocky open-coast sites, with marine salinities. However, Miller et al (2011) state: 'This species (Mutimo cylindricus) grows on pebbles in soft sediment, a habitat that is both less frequently colonized by native species and less frequently explored by marine botanists.'

Trophic Status:

Primary Producer

PrimProd

---

Habitats

General Habitat	Rocky	None
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Tidal Range	Low Intertidal	None
Vertical Habitat	Epibenthic	None

---

Life History

---

Tolerances and Life History Parameters

Minimum Length (mm)	230	Stewart 1991
Broad Temperature Range	None	Cold temperate-Subtropical
Broad Salinity Range	None	Euhaline

General Impacts

No impacts have been reported for Mutimo cylindricus on the West Coast of North America.

---

References

Aguilar Rosas, Raul (1994) Notas Ficologicas: I. Primer registro de Cutleria cylindrica Okamura (Cutleraceae, Phaeophyta) para la costas del Pacifico Mexicano, Acta Botanica Mexicana 29: 55-60

Alvarez-Canali, D.; Sanson, M.; Tronholm, A. (2024) Arrival of the non-indigenous brown alga Mutimo cylindricus to the Atlantic Ocean, Aquatic Botany <missing volume>(103745): Published online
https://doi.org/10.1016/j.aquabot.2023.103745

Bold, Harold C.; Wynne, Michael J. (1978) Introduction to the Algae: Structure and Reproduction, Prentice-Hall, Englewood Cliffs, NJ. Pp. <missing location>

Guidone, Michele; Thornber, Carol; Brian Wysor, Brian Wysor; O’Kelly, Charles J. (2013) Molecular and morphological diversity of Narragansett Bay (RI, USA) Ulva (Ulvales, Chlorophyta) populations, Journal of Phycology 49: 979-995
DOI: 10.1111/jpy.12108

Guiry, M. D.; Guiry, G. M. 2004-2023 AlgaeBase. https://www.algaebase.org/



Hollenberg, George J. (1978) Phycological notes: Two brown algae (Phaeophyta) new to California., Bulletin of the Southern California Academy of Sciences 77(1): 28-35

Kogishi, Keita; Kitayama, Taiju; Miller, Kathy Ann; Hanyuda, Takeaki; Kawai, Hiroshi (1987) Phylogeography of Cutleria cylindrica (Cutleriales, Phaeophyceae) in northeastern Asia, and the identity of an introduced population in California, Journal of Phycology 46: 553-558

Looby, Audrey; Ginsburg, David W. (2021) Nearshore species biodiversity of a marine protected area off Santa Catalina Island, California, Western North American Naturalist 81(1): 113-130

Miller, Kathy Ann; Aguilar-Rosas, Luis Ernesto; Pedroche, Francisco F. (2011) A review of non-native seaweeds from California, USA and Baja California, Mexico, Hidrobiológica 21(3): 365-379

Silva, Paul C.; Menez, Ernani G.; Moe, Richard L. (1987) Catalog of the benthic marine algae of the Philippines, Smithsonian Contributions to the Marine Sciences 27: 1-179

---