Study suggests that the ratio of “wild fish inputs” to “farmed fish outputs” – meaning the weight of wild-caught fishes killed and fed to farmed ones – is between 27 percent and 307 percent higher than previous estimates. In particular, protein “output” from carnivorous species such as salmon, trout, and eel is thought to require more than twice the “input” from wild fishes.
"Aquaculture" is the farming of fishes and other marine life -
Media Credit: Adobe Stock
A new study says that the impact of aquaculture on wild fishes is “greater than commonly cited,” further undermining the widely held belief that it can be part of a sustainable food system [while the English language usually refers to multiple fishes as “fish”, we use “fishes” to emphasize that they are individuals].
The research was led by scientists from the University of Miami’s
Rosenstiel School of Marine, Atmospheric, and Earth Science, Oceana,
and New York University, and was published in the journal Science
Advances earlier this week.
It suggests that the ratio of “wild fish inputs” to “farmed fish
outputs” – meaning the weight of wild-caught fishes killed and fed
to farmed ones – is between 27 percent and 307 percent higher than
previous estimates. In particular, protein “output” from carnivorous
species such as salmon, trout, and eel is thought to require more
than twice the “input” from wild fishes.
For the study, the researchers noted several previously overlooked
sources of wild-caught fishes in aquaculture feed. They also
incorporated data on “collateral fishing mortality,” which includes
seabirds, turtles, marine mammals, and invertebrates as well as wild
fishes.
In addition, the researchers listed abandoned gear and so-called
“processing collateral,” along with the spread of pathogens,
antibiotics, and pesticides to wild populations as additional
factors in the industry’s lack of sustainability. Widespread coastal
degradation and the likely underestimated greenhouse gas emissions
(GHGs) of farming fishes also contribute.
Is aquaculture sustinable?
According to the UK’s Sea Fish Industry Authority, aquaculture is
the fastest-growing food supply sector in the world, expanding more
than 600 percent between 1990 and 2020.
Adobe Stock Trillions of fish are eaten by humans every year, half
of which come from aquaculture
The farming of fishes has become a billion-dollar industry, and
aquaculture alone is responsible for about half of all fishes
consumed by humans. (Around 1.5 trillion individual animals per
year.) This also means aquaculture is complicit in many of the same
injustices – disease, cruelty, starvation, and death – rife in the
farming of terrestrial animals.
The authors of the new study note that more research is needed to
get a true picture of the industry’s impact on the environment and
biodiversity. Concluding, they suggest that all directives to
“expand this sector on sustainability grounds should be
reconsidered.”