36 | New Scientist | 13 February 2021
T
HE fish counter at my local supermarket
has a chalkboard displaying how many
different species are on sale on any
given day. It is usually in the 20s, though
sometimes creeps above 30. As well as staples
such as cod, salmon and mackerel, it often has
trout, sea bass, monkfish, langoustines, tuna,
scallops, squid, catfish and flatfish.
The chiller cabinet next door has more:
jellied eels and cockles in jars, mussels from
Ireland, crab from Indonesia, prawns from
Ecuador. In the canned goods section I can
also find oysters from South Korea, crab meat
from Vietnam, anchovies from the Pacific
Ocean, sardines from the north Atlantic
Ocean and tuna from the Indian Ocean.
The freezers have yet more.
This abundance makes my head swim. I
don’t eat mammal or bird meat, but I do eat
seafood, and I want to consume it as ethically
and sustainably as possible. But I worry about
overfishing and the environmental impacts of
salmon farms and shrimp ponds. Most of the
products on offer bear a label certifying that
they were caught or farmed sustainably, or at
least “responsibly”. What does that mean? Who
checks? Is it even possible? In other words, can
I eat fish with a clear conscience?
Seafood is big business. Every year we
collectively eat more than 155 million
tonnes, about half of it wild-caught and half
farmed. To put that in perspective, we eat
about 320 million tonnes of land-reared meat
a year. Yet consumption of fish is growing
faster than that of meat – around 3.1 per cent
a year versus 2.1 per cent. Since 1950, human
population has grown by about 175 per cent.
In that same time, the amount of fish we eat
has increased by 750 per cent.
This demand is sustained by a fleet of >Features
2.9 million motorised fishing vessels and a vast
and growing fish farming industry. More than
half of the world’s oceans by surface area are
now fished. Despite living on land, humans
are a top marine predator.
During recent Brexit negotiations, fishing
rights were a major sticking point, despite the
fact that this represents a relatively small part
of the economy, both in the European Union
and the UK. But the importance of the issue
underscores the way many feel about an
inherent right to the bounty of the sea.
To learn about the impact of our appetite
for fish, a good first port of call is a report
published every two years by the United
Nations’ Food and Agriculture Organization
(FAO). Called The State of World Fisheries and
Aquaculture (SOFIA), it is a monumental
undertaking. As soon as one edition is
finished work starts on the next.Sea half-empty
The picture that the latest report, published
last year, paints of the world’s wild marine
fisheries is surprisingly positive. Nearly
two-thirds of commercial stocks are classed as
sustainable. That means there are enough fish
to deliver the “maximum sustainable yield”,
which is the most fish that can be caught now
and in the future without the stock becoming
depleted. In other words, the annual catch is
equal to the annual increase in biomass
through growth and reproduction. The FAO
monitors just under 500 fish stocks, which
produce about 75 per cent of the global catch.
Stocks are delineated both by geography and
species, for example north-east Atlantic cod.
By this reckoning, at least half – two-thirds
of 75 per cent – of fish stocks are sustainable.Plenty more
fish in the sea?
As the world’s appetite for seafood explodes, is there
really a way to eat it sustainably, asks Graham Lawton
Let’s call this the “sea half-full” view.
Stocks of the top 10 most-caught marine
species, which together account for a third of
all the fish caught at sea, are more sustainable
than the average. By mass, 78.7 per cent of
seafood that ends up on the market comes
from stocks the FAO deems sustainable.
This rather upbeat assessment, however,
masks a messier situation beneath the waves.
“Many countries do not have research ships to
go to sea and monitor the stocks,” says Manuel
Barange, director of the FAO’s Fisheries and
Aquaculture Policy and Resources Division.
Even when they do, the science is challenging.
It requires an estimate of the total biomass of
a species within a huge geographical area, and
then an assessment of whether that is enough
to support the maximum sustainable yield.
The margin for error is so large that a stock
is considered sustainable even if it is 20 per
cent lower than needed for the maximum
sustainable yield.
Even with this wiggle room, the FAO says
that about a third of the fish stocks it monitors
are overfished, and hence on the road to
collapse if nothing is done to stop the plunder.
In 1974, when the FAO first started counting,
90 per cent of stocks were sustainable. Today,
just 65 per cent are. Even if the level of fishing
stays the same, stocks will continue declining.
This is the “sea half-empty” view. “We cannot
allow this to continue,” said Qu Dongyu, the
director general of the FAO, at the launch of
the latest SOFIA report.
The failure to stop or even slow the decline
in fish stocks has happened in spite of three
global commitments to do exactly that. The
first was signed by all 193 member states of
the FAO in 1995: the Code of Conduct for
Responsible Fisheries. Next came the Aichi