Colpomenia claytoniae

Invasion History

General Invasion History:

Colpomenia claytoniae was noted as an 'irregular, convoluted' form of C. peregrina in southeastern Australia by Clayton (1975). It was studied and recognized as a separate species, with a type specimen from Sangjokam, on the south coast of Korea. Specimens were collected from Korea; the Ryuku islands of Japan; Hong Kong; Port Philip Bay, Australia; New Zealand; and Cape Town, South Africa (Boo et al. 2011). We treated the species as a Northwest Pacific native, and the southern hemisphere populations as cryptogenic, but a broader Indo-Pacific native range is possible. Specimens of C. claytoniae were collected in southern California in 1999 and 2010 (Boo et al. 2011).

North American Invasion History:

Invasion History on the West Coast:

Colpomenia claytoniae was collected in 1999 in Corral Canyon State Beach, in Malibu, California, and again in 2010 in San Pedro, California (Boo et al. 2011). It was identified by microscopic and molecular methods. It is likely that this seaweed has a more extensive introduced range on the West Coast. Possible vectors include hull-fouling and ballast water.

Description

Colpomenia claytoniae grows as a bag-like or globular thallus, becoming irregular and convoluted with age. The thallus is covered by an outer cortex of angular, pigmented cells. There are extensive patches of plurilocular (multi-cell) sporangia having 6-8 locules (cells). The locules can be arranged in a single row (uniseriate) or biseriate. The thallus is attached at the base by rhizoid filaments.The thallus grows to 300 mm in diameter, and usually grows on rocks in the lower tide zone.. The thallus is tan to dark brown in color (Boo et al. 2011).

Taxonomy

Ecology

General:

Colpomenia claytoniae grows in its macroscopic phase as a globe or bag-like alga, which is found on rocks in lower intertidal zones. It has a two-phase diploid-haploid life cycle. The macroscopic phase are haploid gametophytes, producing male or female gametes. The female gametes settle onto a solid substrate, and male gametes fuse with them, growing into a short (~5 cells high) filamentous diploid sporophytes, 2-3 mm in diameter, resembling brown cushions (Clayton 1979). However, gametophytes can also release parthenogenetic haploid gametes, which develop without fertilization, and are morphologically identical to the sexually produced sporophytes. Terminal sporangia develop on the filaments, which produce zoospores, and settle and grow into the bag-like macroscopic thalli (Clayton 1979). Colpomenia claytoniae has been found on rocky substrates in the low intertidal zone in Korea, Australia, South Africa, and California (Boo et al. 2011). We do not have specific information on its temperature and salinity tolerances, or its light requirements.

Trophic Status:

Primary Producer

Habitats

Life History

Tolerances and Life History Parameters

General Impacts

The abundance and distribution of Colpomenia claytoniae on the West Coast are poorly known, and no impacts have been reported.

References