A carbon footprint measures the total greenhouse gas emissions, like carbon dioxide and methane, caused by an activity, product, or organization. A “fish carbon footprint” specifically refers to the overall greenhouse gas emissions linked to fish from its origin—whether wild-caught or farmed—to your plate. This includes every stage of production, processing, distribution, and waste management.
What Contributes to Fish’s Carbon Footprint
For wild-caught fish, a primary contributor to greenhouse gas emissions is the fuel consumed by fishing vessels. These diesel-powered boats release significant amounts of carbon dioxide. The type of fishing gear employed also impacts fuel usage; for example, catching crustaceans like crab or shrimp often requires more fuel due to practices like dragging heavy dredges, while purse seining for anchovies or mackerel can be less fuel-intensive.
In aquaculture, energy consumption in various operations drives emissions. This includes energy for pumping water, aeration, and temperature control within farming systems. Feed production stands as a major source of emissions for many farmed finfish and crustaceans. The ingredients in fish feed, such as soy, rapeseed, and wheat, contribute to emissions through their cultivation, processing, and transportation.
The processing of fish adds to its carbon footprint, including energy used for filleting, freezing, and canning. Transportation of fish from capture or harvest to processing facilities and then to markets and consumers also generates emissions, especially when long distances or air freight are involved. Waste management from both wild fisheries and aquaculture operations further contributes to greenhouse gas emissions.
Wild-Caught Versus Farmed Fish Emissions
The carbon footprints of wild-caught and farmed fish differ based on their primary emission drivers. For wild-caught fish, the largest contributor to emissions is the fuel burned by fishing vessels. The efficiency of these vessels and the specific gear used play a significant role; for instance, bottom trawling consumes substantial fuel. In contrast, methods like gillnets, seine nets, or hook-and-line fishing generally have a lower fuel impact.
Farmed fish emissions are largely influenced by feed production, which can account for a significant portion of the total carbon footprint, sometimes as high as 70-90% for certain species. The composition of this feed is a factor, with reliance on wild fish for fishmeal or soy from deforested areas contributing to higher emissions. Energy use in aquaculture operations also adds to the farmed fish footprint. While some studies indicate that farmed salmon can have a lower carbon footprint per kilogram compared to wild-caught salmon, other farmed species like prawns/shrimp may have higher emissions than their wild counterparts.
The carbon footprint values for both wild-caught and farmed fish can vary widely depending on specific practices, species, and geographic location. For example, farmed finfish generally range between 4 and 6 kg CO2e per kg carcass weight at the farm gate, while cultured bivalves have much lower values. Wild seafood, on average, generates less carbon per unit of protein than beef and pork, often having a carbon footprint similar to poultry. The environmental impact depends heavily on how the fish is caught or raised, emphasizing that individual practices within each category truly determine the footprint.
Reducing Your Fish Carbon Footprint
Consumers can significantly lower their fish carbon footprint by making informed choices about the species they consume. Selecting lower trophic level fish, such as sardines or anchovies, results in a smaller carbon footprint because these species require less feed and energy input. Mussels and clams, being filter feeders, also have a negligible carbon footprint as they do not require external feed and can even help purify surrounding waters.
The sourcing of fish also impacts its environmental footprint, with locally sourced fish often having a lower transportation-related carbon footprint compared to imported varieties. Consumers can investigate the origin of their seafood to understand the distance it traveled. The fishing or farming methods employed greatly influence emissions. For wild-caught fish, choosing options caught with passive gear like pole-and-line or handlines, which are less fuel-intensive, can reduce impact compared to methods like bottom trawling that consume more fuel.
When considering farmed fish, supporting aquaculture operations that prioritize sustainable practices makes a difference. This includes farms that use more plant-based or alternative feed ingredients, reducing reliance on wild fish for fishmeal, or those that have improved feed conversion ratios. Certifications can serve as a guide for consumers for sustainable choices. The Marine Stewardship Council (MSC) certifies wild-caught seafood from fisheries that meet standards for healthy stocks, minimal environmental impact, and responsible management. For farmed fish, the Aquaculture Stewardship Council (ASC) promotes environmental sustainability and social responsibility in aquaculture systems.