Actualité scientifique
Scientific news
N° 430
April 2013
Actualidad cientifica
Climate threatens the food security
of Pacific islands
© IRD / P. Laboute
Isolated in the middle of the
ocean, Pacific islands rely
closely on fishing for their
economy and food security. But
global warming could
considerably reduce their
accessible fish resources over
the coming decades. This is
what has been revealed in the
journal Nature Climate Change,
a study by the IRD, the
Secretariat of the Pacific
Community (SPC) and their
French, Australian and American
partners. According to IPCC
climate forecasts, the quantity of
coral reef fish, essential for the
inhabitants’ food, could drop by
20% by 2050.
Coral reefs are threatened by climate change.
Good to know
Fishing and fish sales are the first or
second source of revenues for 50% of
households in coastal areas of Papua New
Guinea for example.
Glossary
IPCC: intergovernmental panel on climate
change
Coral bleaching: loss of algae living in the
(white) calcium skeleton of coral, called
zooxanthellae, following stress (rise in
temperature, hurricane, etc.).
Tuna fleeing eastwards
Coral ecosystems threatened
The scientists studied the response of the fish
biomass to climate change in the Pacific, according
to the forecasts of the intergovernmental panel on
climate change (IPCC). Fishing for skipjack in particular, a fish in the tuna family making up 90% of
catches, will be seriously affected. According to the
models, the rise in surface water temperature, greater
in the western ocean, will lead to the migration of
tuna towards eastern Polynesia. Thus, catchment
areas will move away from the Melanesian coast, the
Salomon islands or Papua New Guinea. The exodus
of tuna from the territorial waters of these countries
will be a significant economic loss. Fishing rights
paid by major international fisheries are an important
source of revenue for these small insular Nations.
Along the coasts, the availability of coral fish is also
under threat. Forecast ocean warming will increase
coral bleaching leading to the death of numerous
reefs. Population growth in these territories,
preserved up to now, will also exert strong pressure
on coral ecosystems – exploitation, damage, pollution, etc. The recovery rate of coral reefs should fall
from 40% throughout the Pacific today, to 10 or 20%
in 2050. According to the study, this loss will reduce
by 20% the quantity of coral fish, an essential
resource for local populations.
Sectors to develop
Some Pacific islands could however turn to aquaculture and fresh-water fisheries. On land, it’s a
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Contacts
whole different scenario. The expected rise in rainfall, increasing the surface of lakes, rivers, etc. by
10% by 2050, could be beneficial to these activities. In their study therefore, the scientists are
encouraging the development of these sectors. To
make up for expected losses, they are inviting
governments to facilitate access of local fishermen
to tuna resources – for example by installing fish
aggregation devices, sorts of floating pontoons that
attract them, along the coast. Finally, other fish
resources still unexploited, could be drawn upon,
such as mackerel, anchovy, sardine, etc.
Minimising the risks by preserving reefs and maximising opportunities: a challenge that the public
authorities of these small Pacific Nations will have
to face in the coming decades to cope with climate
change and the increasing need of their growing
population for fish.
Johann Bell, CPS researcher
Tel: + 687 26 20 00
johannb@spc.int
Alexandre Ganachaud,
IRD researcher
Tel: + 33 (0)5 61 33 29 66
alexandre.ganachaud@ird.fr
Laboratory for space geophysical and
oceanographic studies – Legos (UMR
IRD / Cnes / CNRS / university
Toulouse 3)
Keywords
Aquaculture, Climate, Pacific, Fishing
Photos : www.indigo.ird.fr
Partners
CPS, IRD, CLS, UNSW, CSIRO, AIMS, AusAid
References
Bell J., Ganachaud Alexandre, Gehrke P., Griffiths S., Hobday A., Hoegh-Guldberg O., Johnson J., Le Borgne Robert, Lehodey P.,
Lough J., Matear R., Pickering T., Pratchett M., Sen Gupta A., Senina I. and Waycott M. Mixed responses of tropical Pacific fisheries
and aquaculture to climate change, Nature Climate Change, 2013. doi:10.1038/nclimate1838
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indigo@ird.fr
According to the IPCC predictions, skipjack should migrate eastward in the Pacific Basin, towards the French Polynesia (above), to the
detriment of the islands to the west as Melanesia, Solomon Islands, Papua New Guinea, etc..
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