Feather-boa Kelp, Egregia menziesii
Feather-boa Kelp, Egregia menziesii. Underwater photograph taken in coastal waters off San Diego, California, September 2021. Photograph and identification of Bob Hillis, Ivins, Utah.
Feather-boa Kelp, Egregia menziesii. Underwater photograph taken in coastal waters off San Diego, California, September 2021. Photograph and identification of Bob Hillis, Ivins, Utah.
Phylogeny: Feather-boa Kelp, Egregia menziesii (Turner) Areschough, 1876, is a member of the Lessoniaceae Family of Kelp. Algae in this family are not from the plant kingdom, but are from the Chromista kingdom. Chromists are photosynthesizing organisms that used to be known as Protista. This diverse kingdom includes brown algae, diatoms, mildew, and malarial parasites. The Egregia genus is one of five genera in the Lessoniaceae Family, and there are three species in the Egregia genus. The genus name Egregia comes from the Latin meaning “standing out from the flock.” This species was named in honor of the Scottish surgeon, botanist, and naturalist Archbald Menzies who sailed around the world in search of new plant species.
Morphology: Feather-boa Kelp resembles a plant in appearance, but the resemblance stops there. The thallus (body of the organism) is comprised of three organs: the holdfast, the stipe, and the fronds. The thallus is held to the bottom substrate by a root-like holdfast. The intertwined and branched haptera tissue of the holdfast anchors the plant, but does not gather nutrients or water like a root does. The stipe is thick and functions like a tree trunk, connecting the holdfast to the branching fronds. A stipe may support 4-25 fronds. The fronds have a smooth, strap-like, and flexible central axis called a rachis. The rachis is laterally lined with blades and pneumatocysts (gas filled, pear-shaped bladders). The rachis terminates in a leaf-like lamina. The pneumatocysts float the fronds toward the surface and the sunlight. The blades may be long and leaf-like or thin and hair-like. Feather-boa Kelp reach a maximum of 10 m (33 feet) in length.
Habitat and Distribution: Feather-boa Kelp grows on rocks along protected and exposed coastlines. It lives in the intertidal zone and to depths of 20 m (66 feet). Feather-boa Kelp is a temperate to subtropical Eastern Pacific species. It has a limited distribution in Mexican waters where it ranges from Punta Eugenia, Baja California Sur, northward along the central and northwest coasts of the Baja Peninsula.
Reproduction: Feather-boa Kelp alternates between an asexual sporophyte generation and a sexual gametophyte generation. Adult sporophytes reproduce asexually through the production of spores, which produce gametophytes. Gametophytes are microscopic and produce either male (sperm) or female (eggs) gametes. The gametophytes release their gametes into the water where fertilization occurs and forms a zygote. The zygote grows into a juvenile sporophyte. The sporophyte matures and completes the cycle.
Ecosystem Interactions: Feather-boa Kelp is a critical part of many near shore ecosystems. It provides food, structure, and camouflage for hundreds of species of fish, mollusks, crustaceans, and other invertebrates. As the thallus matures and parts slough off, or are torn lose by water movement, they continue to provide food and habitat whether they sink to the bottom, wash up on the beach, or drift into pelagic waters as a kelp paddy.
Human Interactions: From a conservation perspective Feather-boa Kelp has not been formally evaluated, however, it is are very common and widespread in distribution and should be considered to be of Least Concern. Feather Boa Kelp contains many chemicals which are used in the medical, cosmetic, food processing, aquacultural, manufacturing, and agricultural industries. It is harvested commercially and recreationally in some regions.
Synonyms: Egregia laevigata, Egregia laevigata f. borealis, Egregia laevigata subsp. borealis, Egregia menziesii subp. insularis, Egregia planifolia, Fucus menziesii, Macrocystis menziesii, and Phyllospora menziesii.