INFLUENCES TO THE TIMING OF FERTILITY OF AN INTERTIDAL KELP Alaria marginata
The cultivation, production, and marketing of seaweed and seaweed products will likely play an important role in the future of mariculture in Alaska. The common intertidal seaweed Alaria marginata, shows promise for commercial production. However, the environmental and physical conditions that stimulate the release of spores of A. marginata is a significant knowledge gap.
The purpose of this research is to determine the environmental conditions that influence fertility and the release of zoospores for A. marginata. Thalli from two small bays were gathered weekly for two months. Within each bay, two subsites were visited, one on the more exposed side of the bay and the other on the protected side of the bay. Physical measurements, including stipe length, sporophyll number, fertile sporophyll number, and sorus area were taken weekly. Spore release was conducted on the most fertile sporophyll from each thallus. It is hypothesized that water temperature and light intensity are strong influencers of spore release, however, nutrient concentrations and salinity are being analyzed for their possible influence of Alaria's fertility. Preliminary results show that spore release peaked at the beginning of the field monitoring season. Minimal and often zero spore release was observed after June. Furthermore, there were large differences in characteristics related to reproductive potential, such as the number of sporophylls and the area of fertile material on sporophylls, between sites.
Knowing when kelp species are fertile is very critical to mariculture. It is key for industry members to know when wild stock should be harvested to most effectively produce seed in the hatchery.
