Over the years, there has been much focus on the coexistence of offshore renewable energy and aquaculture, two rapidly growing industries that share a common resource: the ocean. Bringing these two industries together has the potential to generate economic, environmental, and social benefits, while addressing multiple challenges from food scarcity to climate change.
The same could be said for aquaculture and maritime ports. As ocean-based industries continue to expand, careful spatial planning is important to reconcile existing ocean uses and manage environmental impacts effectively. In January 2024, a team of marine spatial planning researchers from the NOAA National Centers for Coastal Ocean Science (NCCOS) and the Port of San Diego released a study on spatial planning methods for aquaculture siting.
The goal is to ask whether aquaculture can be accommodated within and around San Diego Bay, a highly trafficked maritime port, and determine the most suitable species and farming practices for the area.
“NOAA has been building programmes on spatial planning, siting and environmental modelling for aquaculture for the past 10 years,” Dr Ken Riley, science branch chief at the NOAA Fisheries Office of Aquaculture, told WF. “The first place to start with aquaculture development is real estate; how do you find the right location? Where is the best location a farm could be built, and the environment could sustain it?”
Riley continued: “We are in the midst of a major local food movement in San Diego and southern California and want to be better connected to our food. The ocean is the next opportunity to farm and produce food for southern California, and the state is already well known for its agriculture. It’s extremely exciting to see how much farming seafood in coastal areas will mean for California’s agriculture.”
Establishing partnerships
Using exclusion analyses and a multi-criteria decision analysis approach, Riley and his team identified specific areas suitable for shellfish and seaweed aquaculture, considering environmental conditions and compatibility constraints. One unique feature of the Port of San Diego, Riley said, lies in areas that could potentially support shellfish and seaweed farming. While working to identify opportunities to grow mussels or kelp in those areas, Riley and his team also focused on 16 to 17 local species of shellfish and seaweed that grow well and are readily adapted to the environment surrounding the port.
“Starting with almost 50,000 acres, we first identified over 9,000 acres that offer promise for aquaculture development,” said Riley. “Our recommendation is that the port partner with local universities and the aquaculture sector to develop, observe and conduct pilot projects to validate the projected growth and performance of different species. Our aim was to identify areas that the port could use and help it decide where pilot activities could occur. Restoration is also a focal area. Abalone species, for example, are declining significantly and may benefit from restoration programmes.”
Having identified exclusion zones such as major shipping and navigation routes, mooring fields, areas for sailing, naval and maritime activities, potential sources of pollution and areas that would require major efforts to get aquaculture approved, a culture systems analysis was carried out. This involved investigating different species and culture system combinations to identify where different systems had potential for success and to gain a detailed understanding of the necessary environmental parameters with regards to culture, equipment and species combinations.
“This is the next step in spatial planning, because an exclusion analysis only reveals the areas where aquaculture could potentially succeed,” said Riley. “The greatest opportunities in and around the Port of San Diego are the farming of oysters and small-scale seaweed farming. Conversations began six to eight years ago at the port on developing the blue economy, with aquaculture and restoration a big part. We now have a follow-on study that looks at the ecosystem services and habitat considerations for aquaculture and restoration projects and how they could go ahead in certain areas, including a former site for marine debris that was restored through NOAA funding.”
Growing acceptance
As aquaculture continues to grow along the US Pacific coastline, the work by Riley and his team offers insights that extend beyond conflict avoidance. By identifying areas with potential for successful aquaculture development, the research supports the growth of sustainable aquaculture and other blue economy industries in and around the Port of San Diego, highlights how ecosystem services from shellfish and seaweed farming can benefit the area and sheds light on bigger issues such as climate change, rising sea levels and what these might mean.
Efforts are also being made to engage with public perceptions and misperceptions of aquaculture and better understand these by working with communities to grow the social acceptance of aquaculture. With plenty of national attention on work by San Diego to achieve its blue economy objectives, feedback has been positive, said Riley, who highlighted that his work is a positive example of marine spatial planning that can be replicated in other ports around the US.
While the study showcases how marine spatial planning can be a powerful tool for decision-making in the development of industries like aquaculture, Riley acknowledged that there are several steps to take to enable shellfish and seaweed farms to operate with minimal disruption in areas like ports.
“NOAA is conducting a number of studies in smart engineering, smart design and smart siting,” he said. “It’s also looking at rising sea levels and increased energy in particular environments, what this might mean and how to make sure that shellfish and seaweed farms are secure, for example anchoring and mooring for stable production systems and minimising biofouling to produce healthy shellfish.
“There are also permitting and regulatory considerations to go through, as well as environmental impact statements. Before establishing shellfish and seaweed farms in its jurisdictional waters, the port will have to work with the state of California and think about comprehensive environmental assessments.”
Local production
Riley and his team have demonstrated that even a busy port like the Port of San Diego can accommodate aquaculture, underlying the important role of spatial planning approaches in economic development and environmental sustainability. The port is now partnering with seaweed farm Sunken Seaweed, San Diego State University and Hubbs SeaWorld Research Institute to explore seaweed production in the port and the waters off California.
A pilot project is underway to better understand engineering, farming and harvesting, and the necessary economic business model for seaweed farming.
Land-based infrastructure at the port such as processing facilities, cold storage and shipping and transport logistics are also key parts of the work, along with workforce requirements and education and training to build that workforce.
“There is a realisation that there’s a gap in southern California, in which the area is not producing as much as other waters around the US,” said Riley. “We’ve worked for over a decade with the port of Ventura, a little further north of San Diego, with Los Angeles and the port of New Bedford, the largest commercial fishing port in the US. There is a lot of conversation with other ports, but our San Diego study was the first. It’s the seed that spawned the conversation, and we’re excited to see how things develop.”
