there ius no free lunch
I struggle when the discourse about sustainability gets levelled up to “no environmental impact”… which is an impossible basis for discussion.
If we want no environmental impact from anything we do or eat… then there is only one option: for all of us to die right now… anything else requires compromise… where that compromise starts is a matter of public policy and personal choice.
Drastic, perhaps, but look around you: wherever there is a building, a road, a farm, a mine, a port, a hospital… name it there was just nature in the past, and not now anymore…
I find it sometimes puzzling when I hear the critics of bottom trawling when they say: “imagine a bulldozer going over the land and removing everything on its way”… and I look outside and that is what I see… in fact if I fly from Auckland to Invercargill other than a few bits that are protected areas, or soils too poor or ravaged to maintain trees… is all burned or ploughed land… so I don't really get the metaphor. (btw… my take is as with any food production system, trawling has impacts that are highly dependably on the type and depth of bottom substrate – benthos-, of course trawling over pristine seamounts or coral reefs is not the same that over sandy muddy bottoms… that should be the basis of public policy… and if you disagree with the decisions… then make it a matter of personal choice and don’t eat orange roughy - as I do) yet be aware that as long as you are alive you are causing environmental impact.
Now if you talk about the environmental impact of food, then we also need to consider that there is benefit in terms of food production that people eat… primary production is not about “pleasure” at a cost to the environment as with “motorsports, jet skis and most forms of motorised water sports”
So I find it interesting when papers come that actually not only compare the “environmental cost” of seafood production against other forms of food but also measure the nutritional benefits of those foods… which is not an easy task if it is to be done well.
And this paper does it without being too ambitious…I got to it via the good people of sustainablefisheries-uw.org and the original paper is freely available here… as usual, I just quote the abstract and conclusions
Abstract
Recent discussions of healthy and sustainable diets encourage increased consumption of plants and decreased consumption of animal-source foods (ASFs) for both human and environmental health. Seafood is often peripheral in these discussions. This paper examines the relative environmental costs of sourcing key nutrients from different kinds of seafood, other ASFs, and a range of plant-based foods. We linked a nutrient richness index for different foods to life cycle assessments of greenhouse gas (GHG) emissions in the production of these foods to evaluate nutritional benefits relative to this key indicator of environmental impacts. The lowest GHG emissions to meet average nutrient requirement values were found in grains, tubers, roots, seeds, wild-caught small pelagic fish, farmed carp and bivalve shellfish. The highest GHG emissions per nutrient supply are in beef, lamb, wild-caught prawns, farmed crustaceans, and pork. Among ASFs, some fish and shellfish have GHG emissions at least as low as plants and merit inclusion in food systems policymaking for their potential to support a healthy, sustainable diet. However, other aquatic species and production methods deliver nutrition to diets at environmental costs at least as high as land-based meat production. It is important to disaggregate seafood by species and production method in 'planetary health diet' advice.
Conclusion
Food production varies in terms of its environmental impact and its capacity to meet nutritional needs; this research combines these two factors, comparing products across plants and ASFs from terrestrial, capture fishery and aquaculture production systems, to identify foods and production system that provide nutrition at lower environmental impact. Foods sourced from plants as well as bivalve and carp aquaculture and small pelagic fisheries tended to have the lowest environmental impact given their nutrient richness to meet dietary requirements across a diversity of nutrients. In contrast, beef, pork, crustaceans, prawns and pangasius catfish had the highest environmental impacts given their nutrient richness. The contribution of plant-based foods discussed here supports the existing literature, but the potential role that certain species of fish can play in meeting dietary guidelines provides a novel insight to identify nutrient-rich sources that not only combat malnutrition but also reduce environmental impacts of the entire food system.