My doctoral research investigates the social and ecological dimensions of aquatic food production. Advised by Anne Kapuscinski (main), Daniel Press, and Katy Seto, I will explore sustainable alternatives for aquaculture feed (“aquafeed”) ingredients, integrated agriculture-aquaculture (IAA), and seafood consumption patterns to develop pathways toward a sustainable, climate-resilient global food system.  

Aquaculture is the world’s fastest growing food sector [1]. The global demand for fish has skyrocketed due, in part, to shifting consumer consumption patterns— growing 97% between 2000 and 2010 [2]. As a result, fish farms that have long relied on wild stocks to produce fishmeal (for protein) and fish oil (for lipids) for feeds have ramped up production. This approach has diminished ocean stocks and raised fishmeal and fish oil prices. To compensate, feed companies partially substitute fish-based ingredients with soybean [3] and corn [4], simply transferring socio-environmental burdens from ocean to land. And yet, despite increasing use of terrestrial crops in aquafeeds, food production research in the United States has focused little on the possibility of integrating aquaculture and agriculture such that the relationship is reciprocally advantageous, instead of unidirectional.

I focus on the intersections within this network of issues. Aquafeeds pose the largest environmental [5] and economic[6]burden on the aquaculture supply chain. My research seeks to dually address these dimensions of sustainability by identifying low-cost, commercially viable, ocean-friendly alternatives. During a gap year between junior and senior years of college, I worked with Prof. Kapuscinski’s team, then at Dartmouth, to identify a fish-free, microalgae-based feed that yields comparable or better growth and digestibility for tilapia. With a new recirculating aquaculture facility being built on UCSC’s organic farm, I will continue to explore sustainable feeds and expand our research to other fish species. 

Using the aquaculture effluent, I will experiment with fertigation (fertilization-irrigation) of terrestrial crops. Specifically, my work seeks to match the waste produced by specific farmed species and feed mixes with the terrestrial crops’ nutrient and water requirements to generate a mutually beneficial relationship between aqua- and agriculture. I will also include a policy component to examine the regulatory obstacles, and opportunities for IAA permitting and scalability.  

Finally, to understand the broader forces that drive shifts in aquaculture, I plan to analyze recent consumption trends, such as the rise of poke and sushi, and their fishery impacts. These data will be complemented by consumer surveys. I also hope to disentangle links between labeling and consumption. Consumers care more than ever about the sourcing of their food; what effects might you see in buying trends if we implemented an IAA label for both fish and produce? Are there analogies or lessons learned from Fair Trade or Organic labels for terrestrial crops? By illuminating the seafood value chain, we will better understand the fisheries-aquaculture dynamic as well as the future of fish consumption.


[1]FAO. 2018. The State of the World Fisheries and Aquaculture 2018 - Meeting the sustainable development goals. Rome. 223pp. 

[2]Shepherd, CJ & Jackson, AJ. 2013. Global fishmeal and fish-oil supply: inputs, outputs and markets. Journal of Fish Biology83(4)

[3]Ytrestøyl, T, Aas, TS and Åsgård, T. 2015. Utilisation of feed resources in production of Atlantic salmon (Salmo salar) in Norway. Aquaculture 448: pp. 365-374

[4]Khalifa, NSA, Belal, IEH, El‐Tarabily, KA, Tariq, S and Kassab, AA. 2018. Evaluation of replacing fish meal with corn protein concentrate in Nile tilapia Oreochromis niloticusfingerlings commercial diet. Aquaculture Nutrition 24(1): pp. 143-152 

[5]Bohnes, FA, Hauschild, MZ, Schlundt, J and Laurent, A. 2018. Life cycle assessments of aquaculture systems: a critical review of reported findings with recommendations for policy and system development. Reviews in Aquaculture. 

[6]Arru, B, Furesi, R, Gasco, L, Madau, F and Pulina, P. 2019. The Introduction of Insect Meal into Fish Diet: The First Economic Analysis on European Sea Bass Farming. Sustainability11(6): 1697

 © 2019 by Ashley Y Bae 

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