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Sustaining fish supplies for
food security in a changing climate
Edward H. Allison, The WorldFish Center, Penang, Malaysia; Manuel Barange, Plymouth Marine Laboratory, UK;
Nicholas K. Dulvy, Simon Fraser University, Department of Biological Sciences, Canada
W
hen we think of food security, we tend to think of
subsistence agriculture. Can a smallholder farming
family grow enough maize, rice, millet or wheat to
feed itself? Of course, food security is more complicated and
in a market economy even smallholder farmers in remote areas
buy some of their food by selling their surplus crops. Being food
secure also means more than just ingesting enough calories.
Nutritional balance and food quality are also important to chil-
dren’s development and to healthy adulthood.
Health advice in developed countries is to eat more fish and less red
meat. Fish is even more important to the food security of citizens of
developing countries, both as a source of income and as a component
of healthy diets. Currently, one-third of the world’s six billion people
rely on fish and other aquatic products for at least one-fifth of their
annual protein intake. In addition, catches by subsistence and arti-
sanal fisheries make up more than half of the essential protein and
mineral intake for over 400 million people in the poorest countries
in Africa and south Asia.
1
Fisheries and aquaculture directly employ
over 36 million people worldwide, 98 per cent of them in developing
countries. Overall, there are approximately 520 million people whose
lives depend on sustaining fisheries and aquaculture. The sector also
supports global trade worth over USD78 billion in 2008.
2
Sustaining these benefits is a critical challenge, as over half the
fish we eat is still caught in the wild. The other half comes from
fish farming, or aquaculture. A large proportion of wild-caught fish
not directly eaten is turned into fish oil and meal, which goes into
feeding farmed fish and livestock. These supplies, as of 2006 total-
ling 92 million tonnes from capture fisheries and 52 million tonnes
from aquaculture, are threatened by overfishing, pollution and now,
by climate change.
3
The potential impacts of climate change on fishing
communities and fish supplies
Climate change is accelerating and is already affecting marine ecosys-
tems and services. Both models and observations indicate that the
world’s oceans are warming and patterns in atmospheric variability
are changing – resulting in changes in currents, sea ice distribu-
tion and light supply to the surface ocean. Biological responses to
these changes are visible, but variable. Some waters may become
more productive, while others will fail to sustain fisheries at histori-
cal levels.
4
Always unpredictable, fishing may increasingly become
a lottery as migration routes and spawning and feeding grounds
change from those that fishers have learnt to harvest. More certain
are the impacts of rising sea temperatures on ‘bleaching’ of coral
reefs – a phenomenon which results in coral death,
erosion of reefs and reduction of their capacity to
support fish populations, as well as damaging one of
our natural defences against storm waves.
5
Climate change also directly impacts on fishing
and the lives of fisherfolk. Predictions for increased
frequency and severity of extreme climate events –
storms, floods, droughts – coupled with rising sea levels
and melting glaciers at the headwaters of major rivers,
will leave fishing communities, along both rivers and
coasts, increasingly vulnerable to disasters that damage
infrastructure and threaten human lives and health.
6
Climate change may thus profoundly affect fisheries
and aquaculture and their contribution to local liveli-
hoods, national economies and global trade-flows. The
future consequences for global fish supplies are uncertain
and subject to ongoing analysis. But what is certain is
that there will be winners and losers, and that the losers
will be those who don’t have much already. Every major
report on climate change published recently indicates
that the poorest people, living in climate change sensitive
areas such as floodplains and low-lying coastal areas, will
be the most adversely affected and least able to adapt.
7
This observation pertains to the fishery sector too.
In a recent analysis it was demonstrated that African
and southeast Asian countries are the most economi-
cally vulnerable to climate change impacts on fisheries
and aquaculture sectors.
8
This arises from a relatively
high reliance on fisheries combined with low levels of
societal capacity to adapt to anticipated temperature
increases. Of the 33 nations identified as being most
vulnerable, 19 are among the world’s least developed
countries, whose inhabitants are twice as reliant on
fisheries for food as those of more developed nations.
Not only are the most vulnerable countries highly
dependent on fish for protein, they also rely on fishery
products as a source of income, producing around 20
per cent of the total tonnage of global exports, worth
about USD6.2 billion.
African and southeast Asian nations face the double
jeopardy of high vulnerability to climate effects on both
their fisheries and agriculture sectors. By 2050, global
yield of rain-fed maize is forecast to decline by 17 per cent
and irrigated rice by a fifth as a result of climate change,
with sub-Saharan Africa and south Asia the worst hit.
9
T
he
I
mpacts
and
I
mplications
of
C
limate
C
hange
and
V
ariability