I have just published an article which formed the second major part of my master’s thesis research. This article is published in Fish and Fisheries and is available here.
This research builds on previous work on the different environmental and ecological impacts associated with fishmeal sources. We compare different sources of fishmeal with two different measures: a carbon footprint and a marine footprint. A carbon footprint is the total greenhouse gas emissions associated with a product or service. A marine footprint is a measure of the total photosynthesis (expressed in weight of carbon) required to sustain a given level of marine organisms (usually fish). Taken together, these two measures form broad proxies of the environmental and ecological impacts of harvesting fish that can help in informing more or less sustainable options.
Our main findings echo previous findings that targeting fuel-efficient fisheries and low-trophic level organisms generally provides the lowest impact fishmeal and fish oil sources. High trophic level organisms need more base level of photosynthesis to sustain themselves and their growth, and thus have an exponentially greater marine footprint. Fisheries with low fuel inputs (often because of the fish behaviour, fishing gear, and a healthy population status) will have lower carbon emissions and a lower carbon footprint.
We then took these findings and compared them to some new and exciting work on
planetary boundaries. While not all of these boundaries were relevant to this work, our progression towards reaching this for climate change is obviously important. While fisheries are not the largest contributor to global greenhouse gas emissions, it is important to evaluate the benefits we receive from a sector to the full costs. We found that global reduction fisheries have an estimated annual carbon output of 0.04% of humanity’s global carbon limit. While this may seem small, this is one part of fisheries and one that does not directly yield food for human consumption. As more research is done on evaluating environmental impacts in this way, we can see the relative benefits and costs of different sectors, and especially trade-offs within food production as a whole.