Carbon footprint of finfish smaller than meat: study
If you want to reduce the carbon intensity of your diet, you should develop a taste for herring and regard shrimp and lobster as an occasional treat, according to a UBC-based researcher.
Small, oily fish such as herring, sardines and anchovies that school in large groups require only tiny amounts of fuel to catch, as little as 20 litres a tonne.
That means they produce a fraction of the greenhouse gas emissions of pork, lamb and beef, according to a study published by the journal Nature Climate Change. Unfortunately, we use most socalled forage fish to produce fish meal and oil, rather than eating them.
“We aren’t really realizing the nutritional benefit of those fisheries, nor the full benefit of their low impact,” said lead author Robert Parker, a post-doctoral researcher at UBC’s Institute for the Oceans and Fisheries.
“Alaskan pollock is also pretty low carbon compared with other cod-like, fish ’n’ chips style fish,” he said.
Most finfish, including Pacific salmon species that are caught by purse seines and gillnets, have a lower carbon footprint than red meat and about equal to chicken. Farmed fish grown in ocean-based pens can produce even less greenhouse gas.
Tuna is a fish you need to choose carefully.
“Skipjack tuna has a relatively small footprint according to the studies we looked at,” he said. “But albacore longline fishing requires a lot more fuel than purse seining for skipjack. Trolling for bluefin requires more fuel again.”
Lobster and shrimp fisheries require large amounts of fuel relative to the amount of food they produce and when they are flown live around the world, the arithmetic gets downright messy.
“We’ve seen consistently all around the world that crustaceans require a lot of fuel to catch,” Parker said.
“If we can change the way (crustaceans) are caught, that’s where we can have the biggest (carbon) impact.”
While the total amount of seafood landed by the world’s fishing fleets was stable during the 21-year period of the study, greenhouse gas emissions attributed to fishing increased 21 per cent, most of it due to a 60 per cent increase in the popularity of crustaceans.
Australian lobster fisheries are particularly inefficient.
“At the dock, Australian rock lobster produces three times the emissions of Atlantic lobster,” he said.
The globalization of the seafood market isn’t helping either.
“A lot of Australian lobster is flown to China, while lobster from Nova Scotia is flown live to South Korea where there is demand for it,” said Parker.
Seafood aquaculture generally has a very low carbon footprint, but there is a big range within the sector.
Ocean-based aquaculture produces few emissions, while landbased aquaculture requires large amounts of energy, which is especially damaging where electricity is coal-fired.
At its worst, the emissions rival beef production.
Atlantic salmon produced in a land-based facility in the United States has twice the carbon intensity of an ocean-based net pen in Norway, according to a recent study in the scientific journal Aquacultural Engineering.
When comparing the carbon footprint of just the production of land-based salmon and open net-produced salmon, the carbon intensity was “7.01 versus 3.39” when measuring kilograms of carbon dioxide equivalent per kilogram of live salmon, the authors conclude.
But access to abundant hydroelectric power could give British Columbia a big carbon advantage over most jurisdictions when it comes to land-based aquaculture, Parker said.