PREDICTING THE IMPACTS OF LARGE SCALE SEAWEED MARICULTURE ON WILD FISHERIES

Globally, the seaweed market is projected to more than double from approximately $4 billion in 2017 to more than $9 billion by 2024 (Allied Market Research 2018). This is in part due to the diversity of  products derived from seaweed, which span biofuels, food, hydrocolloids, and bioplastics. Seaweed farming has occurred for centuries in locations with strong cultural connection to algal products, mostly in Asia. To date, however, domestic seaweed culture  operations have been relatively small or land-based, due to market and regulatory limitations. In addition to a growing culture behind seaweed products in the U.S., The Department of Energy is exploring large-scale offshore seaweed mariculture for biofuel production (DOE ARPA-E program). The United States' extensive coastline and nutrient rich waters make it ideal for this type of mariculture, and several applications for offshore seaweed farms are currently under review. As we work to make offshore culture a reality there are still many unknowns about how these massive farms will impact wild fisheries and the fishing communities that depend on them.

While the ability of wild fisheries to supply society's demand for healthy marine-based protein has grown insufficient, as global wild fisheries yields have remained relatively stagnant over the past few decades, fisheries do still provide a substantial portion of marine derived protein to human diets. Therefore, as we push farming out into the wild ocean, it is important to understand how these farms will impact our wild fish resources. Seaweed farming tends to evade the detrimental pollution and eutrophication we've seen from fed mariculture species. So could moderate levels of nutrients and increased structur e aggregate or provide refuge for commercial species? C an we anticipate how wild fisheries will react to a mariculture farm in order to better plan and manage new farms? We constructed a framework to predict the responses of wild fisheries to dif ferent seaweed mariculture designs and management strategies. Applying  lessons learned from the implementation of marine protected areas and resulting chages to population dynamics, this multi-species bioeconomic model estimates the total benefits from fishing and farming relative to a baseline yields in the absence of a farm.