Is a seafood diet good for the planet?

Perhaps one of the most important ecological issues facing people who want to add more seafood to their diet is knowing which varieties of seafood are harvested in a sustainable manner. Fisheries can only endure when seafood is captured, grown, or collected in a manner that is, in the long term, not detrimental to the overall health of seafood populations and marine ecosystems. We all need to know that what we eat for dinner tonight isn’t going to compromise our ability to enjoy the same meal two years or twenty years from now.
More than half of the fisheries of the world are categorized as either “fully exploited” or “over exploited.” Essentially, too many fishermen in too many boats are fishing for too few fish. When this happens, fish populations are overfished and catches decline. In response to declining catches, boats often fish longer and try new sites or new methods. Increasing fishing efforts and using technologically advanced gear to locate and haul in catches both exacerbate the problem. Short-term increases in catch may be achieved, but eventually they result in even more devastating drops in fish populations.
At the present time it is clear that marine fishery resources are not limitless, as was once believed. For hundreds of years, man has fished various stocks to depletion and then moved on to repeat the process in a different location, or with a different species. The size of fish that are being caught has become progressively smaller. The important giant breeder fish have been removed from many stocks. Fishers have overfished the top predators and then continued fishing down the food web. It is clear that with the world population now over seven billion, we cannot expect business-as-usual fisheries to be able to provide enough seafood to satisfy world demand. Most fisheries are not sustainable. Yet, sustainable fisheries are the only hope we have to be able to enjoy seafood now and in the future without endangering seafood populations. In order to understand the importance of eating sustainable seafood in our diet, we need to consider the journey from the sea that ends as food on our plates.


Which fisheries are sustainable?

Species that grow rapidly and have large populations are better suited for sustainable fishing than slow-growing species. Small pelagic fish, i.e., fish that spend virtually their entire lives in the water column, continuously swimming in immense schools, are examples of fast-growing species that can be sustainably fished. Although industrial fisheries target many of these fish for processing into fish meal and oil, some make fine human food as well. These include herring, sardines, and anchovies.

The herring family (Clupeidae) consists of over 200 fish species of great ecological and economic significance, including alewife, herring, menhaden, pilchard, shad, and sardine species. Typically, clupeids are small, silvery, streamlined fish that feed on plankton. Some herring species feed as primary consumers, eating phytoplankton, and others feed as secondary consumers, eating zooplankton. Their biomass fuels many marine food chains, including as bait in lobster and salmon fisheries. Various herring species comprise roughly 50 percent of the annual global production of capture fisheries. Commercially important species include Atlantic herring (Clupea harengus), Baltic herring (Clupea harengus membras ), Pacific herring (Clupea pallasii), European pilchard (Sardina pilchardus), and Atlantic menhaden (Brevoortia tyrannus). Of these fish, only menhaden is not consumed as a human food. Herring is marketed in a variety of forms, including filleted, marinated, pickled, salted, smoked, and canned. Herring roe is considered a delicacy in Japan, and shad roe is considered a delicacy in the US. Norway, a country with a proud fishing tradition, serves herring in an incredible variety of preparations, at every meal, including breakfast buffets. Scandinavian smorgasbords can feature as many as 20 different preparations of herring. Even the British enjoy traditional breakfasts that feature kippers, i.e., salted, cold-smoked herring.