Incorporating population genomic perspectives into kelp conservation and aquaculture in the Pacific Northwest

Jordan Brian Bemmels , Gregory L Owens

Recent kelp forest declines and growth in the kelp aquaculture industry have fueled increasing interest in ecological and evolutionary research on kelp forests, including kelp population genomics. While many kelp management activities have inherent genetic and evolutionary implications, kelp management in the Pacific Northwest (PNW) of North America has to date made only limited use of species-specific population genetic knowledge. We believe that kelp managers in the PNW are well positioned to begin routinely incorporating population genomic perspectives into their work. Here, we review the state of genetic knowledge in the canopy-forming kelps Nereocystis and Macrocystis from Washington to Alaska and highlight how this knowledge can support four key kelp management activities: restoration, aquaculture, wild harvest, and biobanking. We discuss several potential paradigms for geographic transfer of genetic material, consider the likely impacts of inbreeding and genetic drift in management of small kelp populations, and suggest strategies for protecting the genetic integrity of populations during wild harvest. To inform optimal sourcing strategies for biobanking and outplanting, we also reanalyze genomic data to explore how the number of individuals sampled impacts retention of genetic diversity. In many cases, predictions derived from molecular data and models have accumulated faster than the research community’s ability to validate them in the field. We propose that experimental tests be incorporated into ongoing kelp management operations as an immediate step in transitioning toward a management framework informed by population genomic data and perspectives. Adopting such a framework will improve the likelihood of attaining desirable outcomes in kelp conservation and aquaculture, including as kelp populations adapt to future challenges.