The science of sustainable seafood, explained

Another plant-based seafood startup starts up for the wrong reasons

Prime Roots, a Silicon Valley alternative meat startup, recently announced that production has started on several plant-based seafood products to be released this spring. The Peter Thiel backed company follows many other alternative meat companies hyping the environmental benefits of replacing meat with plant-based protein.

There is no question that replacing cow meat with plant alternatives is better for the environment. Red meat production has one of the highest carbon footprints of any food and is the largest driver of deforestation around the world. Eating less cow and more plants is undeniably good.

Though Prime Roots offers land-animal meat alternatives, it has a specific focus on seafood and touts its alternative seafood as a more environmental choice to commercially-caught fish. A Prime Roots publication from last year promoted their seafood products by citing an often-debunked myth that the oceans will run out of fish by 2048 due to overfishing. That is simply not true. Most of the world’s fisheries are sustainable and, on average, scientifically monitored fish populations are healthy and/or improving.

Replacing fish protein with plants is probably worse for the environment

Sustainably-caught fish are a low-impact food by several metrics. They use no fresh water, herbicides, or pesticides, thus avoiding runoff, water pollution, and eutrophication impacts that plague terrestrial agriculture. Land-use change is one of the most devastating impacts of terrestrial agriculture and livestock production. Currently, about half of all arable land on Earth is used to produce food. Replacing protein from wild-caught fisheries with plant-based protein would require additional land about the size of Spain.

Climate change impacts are species-dependent but generally, fisheries have lower carbon footprints than any animal protein and some plant-based proteins.

Prime Roots’ aim

Environmental impacts of food are measured by life-cycle analysis (LCA). As of publication, Prime Roots did not have an LCA of its products available to compare their proteins’ impacts to the animal equivalent. Prime Roots is unique in that it uses fermented mushrooms as its protein base. Fermentation produces carbon dioxide as a waste product so their carbon footprint would probably be higher than other plant-based alternatives like Impossible Foods. However, Prime Roots promotes their seafood products as solutions to commercial overfishing and depleted fish populations, but most of the seafood-alternative products they are developing have few sustainability problems. They plan to offer plant-based alternatives to salmon, lobster, tuna, and shrimp. Nearly every salmon fishery in the world is sustainable; lobster is generally managed well, but does have a higher-than-average carbon footprint; the tuna product would replace albacore and yellowfin tuna in tuna salad and poke (both species are generally above target biomass levels around world), shrimp is highly variable—some species are good and sustainable, others are not. Of their seafood alternative products, shrimp seems to make the most sense (maybe lobster depending on carbon savings), but the others seem to solve a problem that doesn’t exist. I asked why Prime Roots decided to focus on those specific seafood products but have not heard back as of press time.

Prime Roots will do good for the environment if they get people to replace red meat with a plant alternative. However, plant-based seafood alternatives are not the answer to ending overfishing (improving management is); further, using false information to promote their plant-based seafood products is not cool.

Picture of Max Mossler

Max Mossler

Max is the managing editor at Sustainable Fisheries UW.

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6 Responses

  1. Hey Max,

    In your section about “Prime Roots’ Aim” I have issues with the claims in this sentence: “Nearly every salmon fishery in the world is sustainable; lobster is generally managed well, but does have a higher-than-average carbon footprint; the tuna product would replace albacore and yellowfin tuna in tuna salad and poke (both species are almost always sustainable and low-impact), shrimp is highly variable—some species are good and sustainable, others are not.

    First, I cannot find any source that shows Prime Roots’ objective is to only act as an alternative to wild fisheries. Could their salmon alternative be more sustainable than the worst salmon farms? I think it’d be hard to say it couldn’t.

    Secondly, describing global albacore and yellowfin tuna fisheries as “almost always sustainable and low-impact” seems quite simplistic and problematic. I understand your approach to fishery management is to encourage a bridge between industry and science to create a responsible, rather than reactionary response, but Monterey Bay lists nine albacore fisheries and 15 yellowfin fisheries as red listed or “avoid.” Do you believe all of those fisheries are actually responsibly managed?


    1. Hi Jacob,

      Thanks for the comment. I think your points are both valid and good criticisms. The point I was trying to make about Prime Roots is that they are offering an unhelpful solution to a problem. The best way to improve seafood consumption is to improve the sustainability of a fishery, not replace the fish with a plant-based alternative. I considered changing some wording to reflect that, but hope this comment will clear it up.

      I don’t think Prime Roots only wants to replace wild fisheries – they offer several beef and pork alternatives, but they certainly like to use wrong information about fishing to market their products – see here: https://medium.com/prime-roots/is-flexitarianism-and-ecotarianism-for-you-cdd2d774b14f

      The tuna question is a good one – admittedly I used language that was too simplistic (I did update that wording). Yellowfin and Albacore populations are generally doing well (see link I added). Monterey Bay’s avoid list for those species is usually due to gear type (drifting longlines have legitimate bycatch issues), however most tuna is not caught with those problematic gear types. Again, this is an area where the solution is not to replace fish with plants, it’s to fix the gear issues.
      Of the species mentioned, I think a plant-based lobster could be an environmental win (depending on the LCA data). The carbon footprint of lobster is high due to the constant starting and stopping of vessels setting and collecting traps. The only way to reduce that footprint is to replace diesel engines with sail or electric ones (possible, but unlikely). A plant-based alternative could be a solution there, but there’s also social impacts to consider with lobster fisheries.

      Thanks for reading!


  2. Thanks for the article Max, and agree that we need to be kicking the tyres hard on any new technology that claims to lower our species’ footprint.

    However, I do have a couple of comments:

    1) How do you figure that “Most of the world’s fisheries are sustainable”? Seems like a very rose tinted view of the world, as judged by your colleagues’ work on the subject, e.g.:

    Costello et al. (2016): “Current status is highly heterogeneous—the median fishery is in poor health (overfished, with further overfishing occurring), although 32% of fisheries are in good biological, although not necessarily economic, condition.”

    Hilborn et al. (2020): “The latest FAO “State of World Fisheries and Aquaculture” report indicates that the fraction of overfished stocks has increased since 2000 (from 27% to 33%), while this study suggests that abundance of stocks is increasing. This probably reflects the bias arising from the fact that the RAM Legacy Database only includes stocks with reliable quantitative stock assessments that come from countries or organizations that perform reliable scientific assessments of their stocks and constitute only half of the world’s catch. We have much less reliable information on the status and trends of the other half of global marine fish stocks, but the intensity of fisheries management is low in these regions, and expert opinion is that the status of these stocks is likely poor and often declining”

    So saying that ‘most’ fisheries are ok seems a bit of a stretch to say the least.

    2) Assuming that there are a significant number of fisheries in need of improvement, and given that the normal prescription (as has been the case in the US) is to reduce fishing mortality (i.e. catches) while the stock recovers, then we are going to need alternative sources of protein to make up the shortfall. In this context Prime Roots can hardly be accused of trying to solve a problem that doesn’t exist. It may be that sustainable aquaculture is a better alternative, but this is not discussed. And of course people may choose plant-based protein on ethical grounds, although those kinds of decisions should probably factor in the impact of agriculture on terrestrial wildlife.

    Those points not withstanding, I agree that we need to be smart about costing each of our food alternatives fully – in terms of their full life cycle environmental and other costs. With a projected 9.8 billion humans to feed by mid century food systems have their work cut out and seafood definitely needs to be play its part, which mean fixing sustainability issues in both wild-catch and aquaculture.



    1. Hi David, thanks for reading. According to the UN FAO – the same SOFIA report cited in Hilborn et al – 33% of fisheries are currently overfished. The fraction of overfished stocks has increased from 27% to 33%, but the others (73% -> 67%) are sustainable. Here is a whole explainer on those statistics: https://sustainablefisheries-uw.org/fact-check/how-many-fisheries-are-overfished/

      Your second point is a fair one, but misses the fact that in most of the world (aside from Asia) fishery management is generally improving. That Hilborn et al paper you cite demonstrates this. We wrote that up here: https://sustainablefisheries-uw.org/fish-populations-are-improving/

      Further, better fishery management will lead to more fish being available for harvest, not less: https://sustainablefisheries-uw.org/new-paper-says-there-is-potential-for-more-fish-and-more-profit/

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