Once a major staple of shellfish consumed along the US West Coast from pre-colonial through the late 1900s, depletion of wild stocks of the California mussel (Mytilus californianus, “CM”) and a lack of hatchery-based aquaculture have eliminated market presence of this species. This is despite a historically high demand in seafood outlets, reaching peaks of 500 tons for annual North American landings through the 1980s. In the US, low-trophic aquaculture (e.g., seaweeds and bivalves) present both environmental and social benefit, and untapped economic opportunities for emerging native species via hatchery-based aquaculture. While oysters traditionally make up a large portion of global shellfish aquaculture, mussels production increased from 2010 to 2016 by ~23% for Mytilid and ~35% for Chilean varieties, demonstrating that demand for mussels, specifically, is on the rise. Here, a collaborative team from Holdfast Aquaculture, Santa Barbara Mariculture, and the Nuzhdin lab at the University of Southern California will report on findings from a USDA sponsored Small Business Innovation Research (SBIR) grant surrounding the amenability of CM to hatchery-based aquaculture. Further, we demonstrate a new seed-to-farm pipeline established exclusively in Southern California, filling an important economic niche for area industry. The team will show that there is potential to introduce CM as a new “California-raised” aquaculture product (trademarks pending), similar to New Zealand’s Green Lipped Mussel (GLM) which is valued at ~$200 million. NZ exports ~68 million pounds of GLMs annually, compared to the U.S. which exported 1.5 million pounds and imported 67 million pounds of mussels in 2019.
In our research, the team demonstrated several key milestones for CM hatchery husbandry and spawning, including: 1) mass-spawns occur regularly, 2) spawn induction is possible (protocols developed), 3) potential amenability to Gamete Conditioning System ripening, 4) settlement onto fuzzy rope, 5) preference for fuzzy rope over other substrates, 6) retention during juvenile re-socking, 7) equal- or out-performance of other Mytilid market metrics (e.g. shell strength, Figure 1). Through grants and investments, new aquaculture facilities have been developed at AltaSea in Los Angeles, where Holdfast Aquaculture can produce 30,000-feet of seeded line per year, and Santa Barbara Mariculture is in the process of developing permits for CM out-planting on their 72-acre farm. The team’s genomics studies demonstrate high mutational load for bivalves, which may impact any selective breeding programs developed for CM and other species. Together, the study data suggests that there is a significant opportunity for US West Coast aquaculture in CM, production of this native species through hatchery-based aquaculture is possible, and that CM performance matches or exceeds currently farmed mussel varieties for the region.