Nereocystis luetkeana (K.Mertens) Postels & Ruprecht (BC)

This is yet another iconic species of kelp found along the BC coast forming extensive nearshore beds (Image A). Although they would never be confused, N. luetkeana is basically an elongated version of its close ally Postelsia palmaeformis Ruprecht. Juveniles start out looking like a generic laminarialean blade that soon develops a small pnuematocyst at the top of the stipe and ontogenic splitting in the blade (Image B). Mature individuals have a long hollow stipe terminating at the enlarged pnuematocyst crowned by the transition zone (where the blade splitting and growth occurs), which bears the numerous fronds that float along the surface (Image C). Plants, reaching >30 m in length, are anchored at there base deep in the subtidal by a compact hapteral holdfast (Image D).

This canopy forming species grows throughout BC, along with the other canopy kelp Macrocystis pyrifera (Linnaeus) C.Agardh. Although typically regarded as an annual species, some individuals can persist for two years. Of course the previous refers only to the obvious sporophyte phase depicted here. The sporophyte alternates with a microscopic gametophyte for which our knowledge of its ecology and longevity in the field is wanting. Beautiful and charismatic, you will have no difficulty distinguishing mature individuals from all other species in the field. The youngest juveniles, however, can be misleading prior to producing their distinguishing features (Image B).

Image A. Stand of N. luetkeana fringing the coast of Alder Island, Gwaii Haanas, BC (GWS019848).

Image B. Juvenile beginning to develop the diagnostic pneumatocyst and ontogenetic blade splitting (subtidal (13 m), Tcenakun Point, Chaatl Island, Haida Gwaii, BC; GWS012568).

Image C. Close up of the transition zone subtended by the pneumatocyst and bearing the numerous elongate fronds (subtidal, Rennell Sound, Haida Gwaii, BC).

Image D. Close up of the compact, but nonetheless hapteral holdfast (subtidal, Bolkus Islands (Kelp bed to NE), Gwaii Haanas, BC).