California Sea Grant College Program

Undaria pinnatifida is an invasive species of Asian kelp that was first discovered in California harbors in 2001 (Silva et al. 2002). It has established itself as a successful invasive species in other countries and the California coast is also speculated to be a beneficial habitat for it. To better understand where this new kelp might spread, how successful it might be, and how to manage it in terms of containment more information needs to be gained on its biology and ecology. Along the coast of California there are a variety of native kelps that play key roles in their habitats. An invasive kelp like Undaria has the potential to compete with, or out compete, some of these native kelps. Since Undaria is a species of kelp it has a heteromorphic life history that includes a microscopic gametophyte stage that has the potential to act as a perennial seed stock. The presence of a seed bank for an invasive species is a very useful reproductive strategy since it could provide an invasive species with multiple opportunities to establish a population in a new habitat. The studies conducted examined this gametophyte life history stage to better understand how it might affect the success of Undaria as an invader in California waters.