Aquaculture is one of the most promising avenues for sustainable seafood production in the coming future. The World Bank estimated that 62% of all seafood will come from aquaculture by 2030. 

Global seafood consumption has more than doubled in the past 50 years, putting a strain on Earth’s oceans and incentivizing the need for reliable seafood production. Currently, 90% of all seafood in the United States is imported, suggesting a large potential market for domestic seafood production. California is one of the states with the highest seafood demands and an expansive coastline, making it a prime candidate for sustainable seafood production. 

However, with such a large potential comes a lot of questions, and for UCSB researcher and Ph.D. candidate Jade Sainz, aquaculture became her main academic interest. 

“I became even more aware of the importance of aquaculture for seafood production and jobs, but also I noticed the many challenges that the farmers face, and also the problems we need to solve as managers to ensure aquaculture sustainability,” Sainz said. 

Her research, published recently in Frontiers in Marine Science, used historical environmental data collected from 1981 to 2008 and reanalysis data to predict the profitability of 223 hypothetical mussel farms along the coast from Point Conception to the Mexico border in a region known as the Southern California Bight. 

The researchers studied mussel farms in the coastal region of the Southern California Bight, highlighting variability in productivity at three representative regions over a 27-year period. / Courtesy of Frontiers in Marine Science

The study used particulate organic carbon, temperature, current velocity and mixed-layer depth as biological parameters which were then fitted to predict how the uptake of light, food, nutrients, etc. would manifest in thriving mussel populations.

There is a significant ecological relationship between the variability of the sea and the effect it has on the mussels, the paper found. 

To show the effects of environmental variability on economic value, the Net Present Value (NPV), commonly used in economics and finance, was used as an economic indicator. NPV takes into account investments and the cost of running the mussel farm, minus the cash flow derived from the profits of the farm. 

The study additionally focused on how climate variability, including oceanic fluctuations such as the Northern Pacific Gyre Oscillation (NPGO), can have a substantial impact on the productivity of aquaculture. A strong correlation existed between the ocean’s fluctuations and the success of these mussel farms, with the NPGO serving “as the main driver for mussel productivity.” 

The research found the best locations for maintaining a stable productive mussel farm despite these changes were between Point Conception and Los Angeles. Farms in the north proved to have a faster recovery time from the effects of the NPGO.

Additionally, the study reported “that productivity in the center region is unstable compared to the North (with high productivity) and the South (lower productivity).” It was thought that the reason the southern region had lower productivity was due to warm currents coming from the south.

The study showed that the NPGO has a large impact on mussel production, but why doesn’t another large oscillation, such as the El Niño Southern Oscillation, have such a significant effect as well?

“The NPGO explains variation of nutrient dynamics in Southern California so this is why this climate trends have relevance for mussels,” Sainz explained.

Also according to Sainz, being decadal trends, the two climate patterns can overlap or influence dynamics. 

“Having a Niño year means that these effects will overlap with the NPGOs, causing a major or minor effect on mussels depending on the phase of the NPGO,” Sainz stated. 

This could be due in part to rain patterns produced by El Niño that supply nutrients and particles through runoff to the mussels, which could have a big impact on their populations. 

While scientific research can help guide the way to a more sustainable future it is difficult to predict how aquaculture may be affected by the impacts of climate change. 

“Climate change is expected to change the atmospheric and ocean mechanisms that regulate climate, including Pacific decadal variability. There is a lot of uncertainty of how this will happen, but according to the body of research on the topic, the variance of these decadal trends tend to increase under anthropogenic forcing,” Sainz said.