The Trend Toward Vegetarian Fish Farming

While there’s been some con­fu­sion over when exactly the world will be eat­ing more farm-raised seafood than wild caught — what’s not dis­putable is that our tra­jec­tory is pointed straight in that direc­tion. (The Food and Agriculture Organization first pre­dicted the mile­stone in 2009 [PDF], but has since revised it to 2015 [PDF].) Since then, the aqua­cul­ture indus­try has been in a race to develop more sus­tain­able and effi­cient feed for all types of farm-raised fish with wildly vary­ing nutri­tional needs — after all, a veg­e­tar­ian tilapia has dif­fer­ent require­ments than a car­niv­o­rous salmon. The trend, how­ever, is to move toward more plant-based options, in part as a way to put less bur­den on the sea.

Why turn to veg­e­tar­ian feed?

Until recently, the indus­try relied heav­ily on low-on-the-food-chain “for­age fish” (also called reduc­tion fish by the indus­try) like her­ring, men­haden, and anchovy. They’re caught by com­mer­cial fish­ing fleets and ren­dered into fish­meal or fish oil, then used to feed every­thing from farmed salmon to cod. (It’s also used in feed for hogs and chick­ens.) But the amount of for­age fish required to grow a pound of farm-raised fish has often been at an unsus­tain­able ratio. At the same time, the global price of fish­meal and fish oil began to rise.

“The price of fish­meal is up to almost $1,500 a ton. Ten or 15-years ago, it was $500,” says Anthonie Schuur, an aqua­cul­ture con­sul­tant and board mem­ber of the California Aquaculture Association.

Worldwide, the aqua­cul­ture indus­try is expected to grow from 65.8 mil­lion tons in 2008 to a whop­ping 100 mil­lion tons by 2030, with no end in sight. According to the USDA, “Over the next 20 years, aqua­cul­ture pro­duc­tion must increase by 500 per­cent.” Just like domi­noes, that growth spurs a greater demand for nutri­ent rich feed, which can trans­late into fur­ther global pres­sure on for­age fish — a prospect that wor­ries envi­ron­men­tal­ists. According to a report by Oceana, aqua­cul­ture con­sumes more than 81 per­cent of the for­age fish cap­tured and “reduced” to fish oil, and approx­i­mately half of those cap­tured for fishmeal.

But the tide is turning.

Protein by any other name will fat­ten a fish

“Five years ago, the farmed-salmon diet was 40-50 per­cent fish meal. Today, it’s in the teens some­where,” says Rick Barrows, lead sci­en­tist and nutri­tion­ist with the USDA Agricultural Research Service. “There are a lot of dif­fer­ent groups out there — the giant salmon indus­try, the shrimp indus­try — that want to get away from fish­meal and fish oil for eth­i­cal [and finan­cial] reasons.”

Those alter­na­tive feeds include a range of solu­tions — every­thing from fish­meal derived from fish pro­cess­ing scraps, to algae-based feeds, spent dis­tillers grains, and feeds pro­duced from ingre­di­ents like bar­ley, flax, and even insects.

The vari­ables are mind-boggling. A trout, a sea bass, and a yel­low­tail fed the same algae-based diet will all per­form dif­fer­ently, in part because of their own nutri­tional require­ments, but also because of vari­a­tions in the algae itself. Even fish­meal derived from for­age fish like sar­dines or men­haden can have incon­sis­tent nutri­tional val­ues depend­ing on the species, or even on the time of year they’re har­vested from the ocean. For the increas­ingly indus­trial aqua­cul­ture indus­try, reli­a­bil­ity of sup­ply is crucial.

Which explains why soy­beans seem to be the cur­rent indus­try dar­ling, in part because of their con­sis­tency, avail­abil­ity, and afford­abil­ity in com­par­i­son to fishmeal.

“Every aqua­cul­ture entity in the world is shift­ing their oper­a­tions to more soy­beans and less fish­meal,” says Schuur.

There are draw­backs to using con­ven­tional com­mod­ity soy­beans. Besides the fact that 94 per­cent of soy­beans are genet­i­cally mod­i­fied and off lim­its to many European coun­tries, many also con­tain unde­sir­able anti-nutritionals, and ounce per ounce they pro­vide less pro­tein than tra­di­tional fishmeal.

High-tech soy

Meanwhile, a non-GMO soy­bean designed specif­i­cally for use in aqua­cul­ture feed is being devel­oped by a sur­pris­ing source — geneti­cist John Schilinger, founder of eMerge Genetics. Schilinger is fre­quently referred to as the “father of GMO soy­beans” for his pre­vi­ous work at Monsanto. But when he launched Schilinger Genetics, Monsanto denied his request to use their patented soy­bean. Instead, he devel­oped his cur­rent line of soy­beans through breed­ing tech­niques, rather than genetic manip­u­la­tion. He has also become at least some­what crit­i­cal of genet­i­cally engi­neered food.

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