Aquaculture (or aquatic farming) is set to be the primary form of seafood production in less than a decade, surpassing all wild-based fisheries with the same rapid growth (FAO 2016). By that time, about 60% is expected to be freshwater (inland) and the other 40% ocean based (marine and brackish).
In the aquaculture arena, there are generally two factors to consider when thinking about aquaculture. First is the environment in which a species is cultivated: freshwater, marine, or brackish. Second is the species being cultivated: finfish (carnivorous, omnivorous, or herbivorous), crustacean, mollusc, or seaweed. Depending on what you quantify as an ‘impact’ will determine the relative ‘goodness’ of the system (my quotes are warning you that it is relative and there are trade-offs…sorry). So, for instance, closed-freshwater fish aquaculture (e.g., tanks) can filter/treat pollution and keep species isolated from the wild, but requires significantly more freshwater, energy, and space as a result. Perhaps this is a suitable trade-off for some species. However, we will most likely never see a tuna farm on land anytime soon. And this is the trade off – of the animals we like to consume, finfish rule (e.g., salmon, tuna) and capture fisheries cannot meet the demand alone. Moreover, many of the fishes with the greatest human health benefits (higher omega-3s) are from the marine environment.
Until recently, marine-based production has been given the proverbial ‘thumbs-down’ by general certification programs (e.g., Seafood Watch – which is currently being updated as we speak) and numerous environmental groups. Much of the opposition appears to centralize around the ‘usual suspects’ of bad practices – pollution, disease, parasites, use conflicts, and impacts on wildlife (Fig. 1). While these can happen, they are not a certainty, nor do they necessarily co-occur. What I mean is, if aquaculture is sited and managed well these issues can be mitigated and/or greatly reduced; which is true for every food system, including fishing and agriculture. For example, fellow colleagues and I conducted a review of the offshore aquaculture literature (70 papers) and uncovered there is still a lot of research that needs to be done, but that by in large, offshore practices appear to promote higher levels of production and significant reductions in pollution, disease, and parasites by simply placing farms in slightly farther, deeper, and higher flow conditions (Froehlich et al. in review). Yet, the distinction between practices and potential for minimizing impacts in a larger food context are rarely considered or discussed.
Figure 1. The most frequently (word per submission) used negative (A) and positive (B) word associations from government elicited public comments. Depicted frequencies from 2011 USA Marine Aquaculture Policy (dark gray), 2008 USA Offshore Aquaculture Gulf of Mexico (GOM) regulatory plan (black), 2011 NZ Policy Legislation Bill (No. 3) for marine farming (light gray), and the 2009 NZ expansion plan for salmon farming (white) in Marlborough marine waters. Figure from Froehlich et al. 2017. Public Perceptions of Aquaculture: Evaluating Spatiotemporal Patterns of Sentiment around the World. PLOS ONE 12, 1: e0169281. doi:10.1371/journal.pone.0169281.
New research (including my own) is coming to light about the benefits aquaculture production can have compared to other forms of protein systems, like livestock and fishing. This includes reduction in greenhouse gas emissions (Tilman and Clark 2014), reduction in feed and space requirements (Gentry et al. in review; Froehlich et al. in prep), and potential for ecosystem services. The latter is particularly interesting in that raising species like oysters and seaweed (primarily marine species) can clean our waters, sequester carbon, and may even provide suitable habitat for wild species. However, research on aquaculture benefits outside of production is limited, but deserves our attention – both from a scientific and consumer perspective (but of course funding is needed to do that…which is easier said than done these days).
Aquaculture is and will continue to be part of the growing food market. So what can we do as everyday fish-lovers? What is ‘sustainable’? Well, there are two prominent certification programs tackling some of that: Best Aquaculture Practices (BAP) and Aquaculture Stewardship Council (ASC) – look for these labels and ask for these standards in grocery stores and restaurants:
Both organizations provide information on their certification criterion and a list of all their certified farms and associated species. Even easier, they list the retailers and foodservices that carry certified farmed seafood (BAP, ASC). In addition, some seafood companies are specifically sourcing from only certified farms (e.g., Love The Wild) and are being very transparent about where and what species are being sold for consumption. In the end, aquaculture, just like other food practices, can have greater impacts if improperly managed. However, if science, policy, and the public study and demand sustainable practices in the sector we can mitigate and minimize how we produce not just seafood, but protein as a whole.