In 2013, Americans ate 14.5 pounds of fish and shellfish. About half of that was produced through aquaculture, also known as fish farming. In fact, if you've ever enjoyed fish like tilapia, you've probably eaten farmed fish. When you consider the declining numbers of wild-caught fisheries around the planet coupled with the fact that, globally, farmed-fish production recently topped beef production, it's clear that aquaculture is rapidly becoming the means by which fish will make it onto our plates.
Why is Fish Feed a Problem?
Maybe you're wondering, "What do farmed fish even eat?" The answer, of course, is other fish, just like fish in the wild - except there's a bit of processing involved. Fish feed comes in the form of pellets made of ground up smaller fish species - like anchovies, herring, menhaden, capelin, pilchard, sardines and mackerel - plus the scraps leftover from the fish made into steaks and fillets for our dinner plates.
The problem comes from the massive amounts of small fish that are turned into fishmeal for the farmed fish. According to The Marine Ingredients Organization, "In 2011 around 17 million tonnes of whole fish out of a total world catch of over 90 million tonnes of fish were used to produce fishmeal and fish oil. Of this..., around 12 million tonnes were used...in aquaculture feed for fish and shrimps." The other five million tons of fishmeal went to other farmed animals including pigs and poultry, or for fish oil for direct human consumption.
Menhaden in the Gulf of Mexico
The menhaden fishery in the US illustrates the problem with fishmeal. In 2014, the US was the fifth largest producer of fishmeal, producing 345,000 tons (Peru was top producer with 850,000 tons). Most of that came from menhaden caught off the east coast and in the Gulf of Mexico; the next largest component came from scraps produced in Alaska's seafood industry.
Over one billion pounds of menhaden are taken each year from the Gulf and the majority is ground into fishmeal or turned into fish oil. Not a problem, according to a recently released plan by the Gulf States Marine Fisheries Commission which concluded that the menhaden fishery in the Gulf is not overfished. But according to The Recirculating Farms Coalition (RFC), the plan doesn't address "taking too many fish from the water to fully provide the ecosystem-based services they can contribute over the long term."
Here's what that means.
Menhaden are near the base of the food chain for Gulf life, which makes them an important food source for marine mammals, seabirds and larger fish. They're also filter feeders that improve the local water quality. Taking too many fish out of the water without fully understanding the impact on water quality or the food situation for larger fish could impact Gulf fisheries that are already at risk from oil spills, dead zones and overfishing.
Global Impacts of Fishmeal
We eat a lot of farmed fish in the US, especially shrimp, salmon and tuna; however, we produce very little of what we're eating. Most of our farmed fish is produced in Asia, primarily in China. In 2012, China produced over 41 million tons of farmed fish. By comparison, the US produced less than 600,000 tons. Because the US imports most of its farmed fish we are, essentially, exporting the environmental impacts of our expanding appetites for high-value fish to other countries that have less stringent regulation of their aquaculture operations. Here's why.
Aquaculture consumes up to 80 percent of the fishmeal produced globally but it is an inefficient use, especially for carnivorous fish. This is because, pound for pound, there is an imbalance of feed required to produce fish. For example, the production of one pound of farmed salmon uses the fish oil from about five pounds of wild fish and the fishmeal from 1.3 pounds of wild fish. According to the Ocean Foundation, "[e]ating carnivorous fish such as tuna or salmon is like feeding cows to lions so we can eat the lions...Both the tuna and the salmon have to be fed a large volume of fish products to become a marketable size and flavor for the wealthy country markets where they are sold."
In order for aquaculture to become a more sustainable source of protein, producers will have to increasingly turn to more herbivorous fish like tilapia and catfish, which would require less fish-based feed. Alternative feed forms will also have to be developed. The soy industry has set its sights on aquaculture for major expansion. This is unfortunate, given the problems with soy production including dead zones caused by fertilizer runoff, the heavy use of mono-cropping, the reliance on GMO technology and inputs - not to mention deforestation done to clear the way for soy crops. Alternative feeds are being developed using marine algae and other plant products, with some promising results.
If, as predicted by the UN, we're going to increasingly turn to fish to meet the protein needs of our rapidly growing global population, aquaculture will have to play a significant role so we don't fish our oceans dry. Finding sustainable sources of fish feed is of paramount importance in the ability of the industry to produce fish in a way that is safe, plentiful and less damaging to the environment.