What Fish Should I Eat? by Don Orth

Fisheries and aquaculture provide protein for a quarter of the world’s population and livehoods for 59.6 million workers. Fish provide a high-quality, easily digested animal protein with essential amino acids, fats, and micronutrients. Greater consumption of fish is associated with a lower risk of dementia, cognitive decline, and cardiovascular disease (Bakre et al. 2018; Marshall and van der Meij 2018).  Eat more fish - it's good for you!  Yet, the diversity of fish and types of fishing makes the selection of what fish to eat more complicated. 

Tuna is a popular food fish worldwide.  Photo by Ashbridge Studios, CC BY-NC-ND 2.0.  Source

One of many challenges to reducing hunger and malnutrition is to eliminate overfishing and delivering seafood in sustainable manner that does not further contribute to climate change.  Globally, 67% of assessed fish stocks are within biologically sustainable levels, which means they are at or above the level associated with maximum sustainable yield (FAO 2018); however, more fish stocks are being overfished.

Global trends in the state of the world’s marine fish stocks, 1974-2015.   Source:  FAO 2018.  CC-BY-NC-SA        

Fish and fish products provide an average of only ~34 calories per capita per day but the daily contribution varies widely by region based on availability of alternative protein sources and cultural preferences for fish.  Annual per capita consumption has more than tripled since 1961 in developing regions where four fish dominate our menu — salmon, sea bass, cod, and tuna (Greenberg 2011).   Many low-income regions of Latin America and Africa, where political instability and civil unrest have stymied economic development, still have very high food deficits.

Contribution of fish to animal protein supply (2013-2015).   Source:  FAO 2018.  CC-BY-NC-SA    

More people are consuming fish than ever before. The admonition to “think global and act local” should translate to eating locally harvested seafood and minimizing costs and unsustainable fishing practices. The Code of Conduct for Responsible Fisheries (FAO 1995) is a guiding framework for implementing sustainable fisheries and aquaculture operations. It sets out international principles and standards of behavior to ensure effective conservation, management, and development of both marine and freshwater living aquatic resources. It also accounts for the impact of fishing on ecosystems, the impact of ecosystems on fisheries, and the need to conserve biodiversity.    

Sustainability is a plastic word (Nikiforuk 2019). A fishery is not simply sustainable or not sustainable.  It’s more complicated and requires many choices.  Most practitioners accept three dimensions of sustainability: social, economic and ecological, but a deeper analysis requires consideration of six dimensions of sustainable development, specifically economic, social, ecological, institutional, ethical, and technological factors (Lam and Pitcher 2012; Aquado et al. 2016). For example, justice relates to equity or the fair distribution of benefits and harm, in terms of ecosystems and social justice. Many issues play into assessing sustainability.  Globally, we should be concerned with issues of seafood safety, bycatch, fish fraud, pollution from fish farms, post-harvest loss and waste, local governance, microplastics, lost and discarded fishing gear, overharvest of forage fish harvesting for fish meal, and many other social and ethical issues. As the trade flow diagrams show us, the source of our seafood is also complicated and most regions are importing much of their seafood. Your choice of fish to eat may depend on where and how it was harvested. 

Trade flows of fish and fish product by continent, share of total imports in value 2016 (%).  Source:  FAO 2018.  CC-BY-NC-SA        

Seafood certification, or ecolabeling, provided by third-parties, such as the Marine Stewardship Council and Seafood Watch, are the beginnings of evaluation of ethical and sustainble fisheries. Fishing practices changed dramatically in response to public outrage over harvest of dolphins in tuna purse-seining.  Fisheries that meet Marine Stewardship Criteria are highly selective for the target species, have limited access, well regulated, enforced, and often involve co-management between government, scientists, and fishers.  Seafood Watch develops fisheries and aquaculture standards to judge and communicate fish to “avoid” and “good” or “best” choices.  A novel aspect of this program rates whether fisheries support human trafficking, forced labor or child labor, as well as a new tool that collects data on carbon emissions (Monterey Bay Aquarium 2018).  These third-party certifications of sustainability have not yet delivered on the promise of price premiums, improved governance, or improved environmental conditions (Roheim et al. 2018). Challenges remain in the implementation of seafood sustainability due to potential for confusion about the overlapping goals of a growing range of sustainability initiatives (McClenachan et al. 2016).  

Three types of seafood sustainability initiatives and example goals of each (McClenachan et al. 2016).

One of the remaining issues of ecosystem justice remains to be solved.  With the expansion of aquaculture, the demand for fish meal has increased.   Small fishes, menhaden, anchovies, sardines, capelin, herring, and others are harvested and sent to reduction facilities that market and sell food to fish and other farms.   These fish, often labeled as forage fish, when overfished, no longer support seabirds and larger striped bass or bluefin tuna at higher trophic levels. 

What fish should I eat?  You can eat the fish you catch locally after you learn about local fish consumption advisories.  Take time to learn more about the fish you purchase to eat and how they were harvested.  Alaska Pollock Theragra chalcogramma had the highest catch of any fish in the world, followed by anchoveta, and Skipjack Tuna Katsuwonus pelamis.   Pollock is a “best choice” option according to Seafood Watch, but the Marine Stewardship Council has certified only the US fisheries for Alaska Pollock. McDonald's Filet-O-Fish contains Alaska Pollock in North America.   Skipjack Tuna is a “best choice” if harvested by trolling or pole-and-line fisheries, whereas the long line and purse seine fisheries is a “good choice” due to concerns of bycatch of dolphins. Tuna fisheries that use purse seines with FAD (fish attraction devices) should be avoided.   How do you know?   Look for the Marine Stewardship Council logo on any fish you purchase. 

I also started to compare the carbon foot prints of wild versus farmed seafood. The Seafood Carbon Emissions Tool was created by scientists at the Monterey Bay Aquarium Seafood Watch program and Dalhousie University. This tool also allows you to calculate the emissions associated with transporting the product to its final destination.   Most highly valued species such as shrimp, prawns, salmon, tunas, groundfish (e.g., cod, hakes, and haddocks), flatfish, seabass, and seabream are traded to the most prosperous markets, while less valued species are exported to developing countries. The US imports 98% of its Atlantic Salmon.  My favorite wild Alaskan Sockeye Salmon turns out to have a very high carbon cost associated with transport  

Since aquaculture provides over 50% of global seafood and the US imports the majority of its edible seafood, expect the supply of farmed seafood to continue to increase.  Hopefully, more of these products will be marketed with third party certification to assure responsible practices. Look for the logo for Best Aquaculture Practices Certification.  Watch for locally grown seafood from farms that use recirculating aquaculture technology and integrate aquaponics with fish production.  A land-based aquaponics farm, Superior Fresh, is expanding operations in Wisconsin on a 720-acre property producing fish and leafy green vegetables.  Superior Fresh is the first land-based Atlantic Salmon producer and the world’s largest aquaponics facility.  The goal is to producing seafood with a smaller environmental footprint than other options.  At a recent Wisconsin Aquaculture conference,  Greg Fischer, Manager of the Northern Aquaculture Demonstration Facility, predicted that Walleye “will be the next big food fish for aquaculture in the Midwest.”  This locally produced fish would reduce demand on wild stocks. 

References

Aguado, S.H., I.S. Segado, and T.J. Pitcher.  2016. Towards sustainable fisheries: A multi-criteria participatory approach to assessing indicators of sustainable fishing communities: A case study from Cartagena (Spain). Marine Policy 65:97-106.

Bakre, A.T. and thirteen coauthors. 2018.  Association between fish consumption and risk of dementia: a new study from China and a systematic literature review and meta-analysis.  Public Health Nutrition 21(10):1921-1932.

FAO. 1995. Code of Conduct for Responsible Fisheries. Rome.  Accessed 17 June, 2019 from http://www.fao.org/3/v9878e/v9878e00.htm

FAO. 2018. The State of World Fisheries and Aquaculture 2018 - Meeting the sustainable development goals. Food and Agriculture Organization of the United Nations, Rome, Italy.  227 pp.  Accessed 17 June, 2019 from http://www.fao.org/documents/card/en/c/I9540EN

Greenberg, P. 2011.  Four Fish: The Future of the Last Wild Food.    Penguin Books, 285 pp. 

Lam, M.E., and T.J. Pitcher. 2012.  The ethical dimensions of fisheries.  Current Opinion in Environmental Sustainability 4:364-373.

Marshall, S., and B. van der Meij. 2018.  Fish and omega-3 intake and health in older people.   Maturitas 115:117-118. 

McClenachan, L., S.T.M. Dissanayake, and X. Chen. 2016. Fair trade fish: consumer support for broader seafood sustainability.  Fish and Fisheries 17:825-838.

Monterey Bay Aquarium. 2018.  Monterey Bay Aquarium Seafood Watch Launches First-of-its-Kind Seafood Slavery Risk Tool.    Accessed 17 June 2019 from https://newsroom.montereybayaquarium.org/press/seafood-watch-launches-seafood-slavery-risk-tool

Nikiforuk, A. 2019.  Against ‘sustainability’ and other plastic words.  The Tyee  2 May. Accessed on 18 June at https://thetyee.ca/Opinion/2019/05/02/Sustainability-Plastic/

Roheim, C.A., S.R. Bush, F. Asche, J.N. Sanchirico, and H. Uchida. 2018. Evolution and the future of sustainable seafood market.  Nature Sustainability 1:392-398.