Climate-friendly aquaculture production could dramatically reduce the seafood industry’s environmental footprint by shifting from resource-intensive finfish and shrimp farming toward bivalves and seaweed.
Aquaculture production surpassed wild-capture fisheries for the first time in 2022, reaching 131 million metric tons globally. However, finfish dominated production at 62 million metric tons while climate-friendly aquaculture production of mollusks reached only 19 million metric tons and seaweed 37 million metric tons, according to the Food and Agriculture Organization. The seaweed category includes spirulina dietary supplements and carrageenan gelling agents rather than food-grade seaweed.
According to research from the University of British Columbia, these current aquaculture trajectories worsen food security, climate impacts, and biodiversity despite industry claims of sustainability. The study published in Fish and Fisheries combined biological and ecological data on farmed species with global production statistics from 1950 to 2023, revealing a troubling pattern.
Current aquaculture focuses on species such as salmon, trout, tilapia, and shrimp, which require fishmeal and fish oil, whose production demands fossil fuels while depleting small fish populations that support marine ecosystems. The industry generates water pollution, disease outbreaks, and the escape of farmed fish into wild populations, undermining sustainability claims.
Climate-friendly aquaculture production through bivalves and seaweed offers multiple advantages. These species require no fish-based feed, filtering water naturally while providing nutrient-rich food high in iron, zinc, and healthy fats. Oysters and mussels improve water quality through filter-feeding, while seaweed absorbs excess nitrogen and phosphorus. The Nature Conservancy and National Oceanic and Atmospheric Administration estimate that this ecosystem service delivers $1,320 to $7,740 in value per acre annually for shellfish and $750 to $10,110 for seaweed.
Seaweed captures and stores carbon while both shellfish and seaweed farms reduce wave energy and stabilize sediments, protecting coastal communities from erosion and storm damage. These farms create habitat supporting fish populations that are 1.6 times more abundant around farms than in nearby natural areas.
Climate-friendly aquaculture production delivers far more than seafood, with seaweed capturing carbon and shellfish farms stabilizing coastlines against erosion while creating marine habitat that supports fish populations nearly twice as dense as those in surrounding natural areas. Photo by Stefan Sebök on Unsplash.
The researchers used biological and ecological traits, including growth rate, body size, nutrient density, thermal tolerance, and carbon sequestration potential, to assess the effects of different farmed species on food security, climate, and biodiversity outcomes. Combining species scores with global production data revealed opportunities for expansion
Scaling shellfish farming in Europe, Africa, and Asia could boost food security through nutrient-dense protein, while expanding seaweed production in the Americas, Africa, and Asia would deliver greater climate benefits. Increasing bivalve or seaweed production across most regions could support biodiversity through multiple pathways.
According to lead author Aleah Wong, a PhD candidate at the University of British Columbia, despite environmental advantages, expanding climate-friendly aquaculture production faces significant barriers. Consumer demand remains low for bivalves and seaweed compared to highly profitable farmed Atlantic salmon and whiteleg shrimp. Rising incomes shifted consumer preferences toward higher-value but less sustainable species, creating market incentives that favor resource-intensive production.
Luke Barrett, a research fellow in aquaculture at Deakin University in Australia, noted intensification pressures from limited coastal space. His research emphasizes that ecosystem benefits from this model depend heavily on farm placement. Farms should not occupy healthy functioning ecosystems, but instead target degraded areas where habitats like reefs or seagrass beds have disappeared or cannot recover naturally. Areas with excess nutrients or sediment from agricultural runoff prove better suited because farmed bivalves and seaweed improve water quality.
Because intensive farming of any species can lead to environmental impacts, resource conflicts, and equity issues, Wong emphasized that sustainable management is required regardless of the species chosen. Even bivalve and seaweed operations can generate problems if improperly sited or managed too intensively.
Achieving production shifts requires government intervention through subsidies and support for small-scale, climate-resilient aquaculture operations. Current policy frameworks often favor large-scale industrial operations that produce high-value species rather than climate-friendly aquaculture that delivers environmental benefits alongside food security.
Wong and Barrett recommend policy changes prioritizing ecosystem services alongside profit generation. Recognizing and compensating farmers for water quality improvements, carbon sequestration, habitat creation, and coastal protection could make climate-friendly aquaculture production economically competitive with resource-intensive alternatives.
Market development represents another critical challenge. Expanding consumer awareness of the nutritional benefits of bivalves and seaweeds while developing value-added products could increase demand. Cultural preferences vary significantly by region, requiring tailored approaches to market development reflecting local tastes and traditions.
Seaweed faces particular adoption barriers in regions without established consumption traditions. Beyond food applications, seaweed offers potential for animal feed, biofuels, and bioplastics, creating diverse revenue streams that support the industry’s growth. However, these applications require additional processing infrastructure and market development.
Technical knowledge transfer proves essential for expanding climate-friendly aquaculture production. Farmers experienced with finfish or shrimp cultivation need training in different techniques for bivalve and seaweed management. Water quality requirements, disease pressures, harvesting methods, and post-harvest handling differ substantially between species groups.
Research and development investments could improve its efficiency and profitability. Selective breeding programs have enhanced the productivity of finfish and shrimp farming over the decades. Similar investments in bivalve and seaweed genetics, nutrition, and production systems could accelerate adoption by improving yields and reducing costs.
Climate change itself creates urgency for transitioning toward climate-friendly aquaculture production. Ocean warming, acidification, and extreme weather events increasingly disrupt conventional aquaculture operations. Bivalves and seaweed demonstrate greater resilience to changing conditions while actively mitigating climate impacts through carbon sequestration and ecosystem restoration.
Successfully scaling climate-friendly aquaculture production requires coordinated action across policy, markets, research, and farmer support. Without deliberate intervention to redirect industry growth toward sustainable species and practices, aquaculture expansion will likely continue to favor profitable but environmentally damaging production systems, undermining food security and climate goals the industry claims to support.
