7th SPC HOF meeting
Vulnerability of Aquaculture
to Climate Change
Tim Pickering
SPC Inland Aquaculture Officer
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One slide describing the main types of species examined
Brief description of the surface climate and/or ocean variables used in your assessment to estimate the direct effects of climate change
Projected changes to habitats that underpin the fishery used to show how indirect effects of climate change on stocks were assessed
Examples of how projected changes to climate, ocean and habitats are expected to affect diversity and abundance of the key
fish/invertebrate species
Projected changes in production of fish/invertebrates in 2035 and 2100 under B1 and A2 in summary table (with confidence and
likelihood ratings).
Management recommendations (adaptations)
Please present a summary table of relevant habitats and the expected percentage changes .
Freshwater fisheries (Chapter 7)
Aquaculture (Chapters 5,6,and 7)
Coastal Fisheries (Chapters 5, 6 and 4)
Oceanic fisheries (Chapter 4)
In addition to the key adaptation measures needed to reduce threats to catches, and harness the opportunities, provided by climate
change, please also include the main management measures needed for the habitats that support your fishery
Outline
• The main aquaculture commodities among PICTs
• Climate variables most likely to affect aquaculture
• How these variables could affect aquaculture
species
• Projected changes in production of aquaculture
commodities in 2035 and 2100 under B1 and A2
scenarios
• Management recommendations (adaptations)
Aquaculture commodities supporting
viable industries in PICTs
• Tilapia Oreochromis niloticus
• Freshwater prawn Macrobrachium rosenbergii
• Seaweed Kappaphycus alvarezii
• Blacklip pearl Pinctada margeritifera
• Marine ornamentals (Coral, live-rock, clam, etc.)
• Saltwater shrimp Penaeus monodon,
Litopenaeus stylirostris
Aquaculture commodities in research
or small-scale commercial phases
• Marine finfish, e.g Batfish Platax orbicularis, Rabbitfish
Siganus lineatus, Milkfish Chanos chanos, Barramundi Lates
calcarifer
• Sea cucumber e.g. Sandfish Holothuria scabra
• Giant clam, trochus, green snail for reef re-stocking
• Others: mud crab Scylla serrata, Pacific oysters, Bush prawn
Macrobrachium lar, Red-claw, Mabe pearl
Projected changes
to aquaculture environments
• Aquaculture in PICTs uses all of
terrestrial-freshwater,
brackishwater, coastal and open-sea
environments
• The projected changes to these
environments are the same as those
described in the presentations today
about Freshwater Fisheries, Coastal
Fisheries, and Oceanic Fisheries
Key climate variables
that could affect aquaculture
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Temperature
Rainfall (flooding, or drought)
Cyclones
Habitat alteration
Sea-level rise
Sea water acidification
How these variables
could affect aquaculture
Fish kill in tilapia cage-culture, Vanuatu
Temperature
• Some aquaculture species (coral,
seaweed) are already at the limit
of their thermal tolerance
• When corals get bleached by
“warm-pool” events,
Kappaphycus seaweed is also
affected
• Temperature and salinity
stresses lead to “ice-ice”and
Epiphytic Filamentous Algae
(EFA) outbreaks
Rainfall
• Patterns of rainfall will change,
leading to more rain in some
places and more drought in
others
• In the tropical Pacific rainfall is
expected to increase, improving
the potential for freshwater
aquaculture in much of
Melanesia
• Some areas may become more
prone to flooding
DFF (Fiji) Ltd Prawn Farm
Cyclone Mick, December 2009
Cyclones
• Cyclones may become
more intense, but less
frequent
• Aquaculture infrastructure
is put at risk by any
cyclone, including
structures and stock in
coastal waters and
installations like hatcheries
on beach fronts
Hunter Pearls hatchery, Fiji Islands
Storm surge during Cyclone Tomas,
February 2010
Habitat alteration
• Warming and acidification are
expected to progressively
degrade coral reefs. Coral
aquaculture depends upon
mother colonies as sources of
fragments for grow-out
• Degradation of coral reefs or
seagrass beds can reduce supply
of giant clam or sea cucumber
broodstock for hatcheries
Sea level rise
• Expected to cause major problems
for the shrimp industry, because
farming operations depend on the
ability to drain ponds quickly and
effectively.
• Sea-level rise threatens the
drainage of ponds, causes loss of
quality because: (1) shrimp harvest
is prolonged so stress is increased;
(2) pond soil cannot be tilled and
oxygenated between pond cycles
Sea water acidification
• Pearl oysters are likely to be
badly affected by long-term
declines in seawater pH
• decreases in calcification reduce
growth rates, lead to more
fragile shells, and may also
reduce pearl quality
• All species that form bones or
shells (finfish, shellfish, shrimp)
could be affected
Shell
defect
Some changes will be “positives”
• Warmer temperature and increased rainfall is
expected to benefit tilapia farming in Melanesia
• Farming of Black Tiger Shrimp Penaeus monodon
in New Caledonia may become practical
• Milkfish fingerlings for capture-based culture will
become available at higher latitudes
Some impacts are indirect
• Future price and availability of fish meal, a
resource itself impacted by climate change, will
affect the profitability of aquaculture that uses
formulated pellet feeds (tilapia, prawn, shrimp,
marine fin-fish)
• Increase in water temperature will increase the
prevalence of pathogens and fish disease in ways
that are hard to predict
Projected changes in production
Aquaculture for food security
• Tilapia, carp and milkfish aquaculture is expected
to benefit strongly from the projected increases in
temperature and rainfall, and to cope with other
changes to the environment even though some of
them are negative
• These projected benefits are expected to be
apparent by 2035, but well established by 2100,
especially under the A2 emissions scenario
• Farmable areas will expand to higher latitudes and
altitudes
Aquaculture for livelihoods
• This should also apply in 2035 to freshwater
prawns, however it may be reversed by 2100 due
to the temperature tolerance of freshwater
prawns and the effects of higher temperatures on
stratification of ponds.
• Most commodities dependent on coastal waters
for hatchery production and/or grow-out are
expected to incur losses of production, albeit at
low vulnerability rating to 2035
• By 2100, the effects of climate change and ocean
acidification on all livelihood commodities are
negative and their vulnerability increases.
• Under A2, seaweed farming and production of
marine ornamentals are expected to have a high
vulnerability, and the culture of pearls a medium
vulnerability.
• Shrimp farming, marine finfish farming and sea
ranching/pond culture of sea cucumbers are likely
to have a low-medium vulnerability
• Vulnerability does not necessarily imply that there
will be overall reductions in productivity of these
commodities in the future.
• Rather, it indicates that the efficiency of enterprises
producing the commodity will be affected (because
adaptation strategies will be needed)
• Total production could still increase if the operations
remain viable (albeit with reduced profit margins)
and more enterprises are launched
Pearl production
• The ‘medium vunerability’ assessment may well
need to be revised ‘downwards’, however, once
the results of research on the effects of reduced
aragonite saturation on the larvae and adults of
pearl oysters, and on pearl quality, are examined
in detail.
• There is little scope for adaptive strategies,
because pearl grow-out depends upon an opensea marine environment
Shrimp production
• Subject to adaptive strategies being adopted, the
goal to double the production of the shrimp
industry in New Caledonia to ~ 4000 tonnes per
annum and 1000 livelihoods could still be met. B
• Similarly, both Fiji and PNG should be able to
retain their potential to produce 1000 and 2000
tonnes per year, respectively, employing about
500 people.
Seaweed production
• Continued selection of more suitable farming
sites, farm methods, and seaweed varieties will be
required to reduce vulnerability of seaweed
culture.
• Production targets of around 500 tonnes per year
for both Fiji and Solomon Islands should still be
achievable until 2035, but not necessarily in the
same places or with the same industry
management methods practiced currently
Management recommendations
Freshwater aquaculture
• Promote the benefits of freshwater aquaculture,
based on tilapia, carp and milkfish, in per-urban
areas and for rural households, to supply fish to
growing human populations that do not have good
access to those coastal and freshwater fisheries
resources likely to be enhanced by climate change,
or to tuna at low cost.
Shrimp
• Identify which existing shrimp ponds can be
modified by elevating the walls and floor to
continue to function under rising sea levels, and
which ones will need to be abandoned in favour of
new ponds further landward at higher elevations.
• Assess which alternative commodities may be able
to be produced in those ponds that are no longer
suitable for shrimp.
• Intensify shrimp production, to better utilise the
reduced area of flat coastal land (sea level rise)
Cyclone-proofing, Pathogens
• Assess designs of equipment and infrastructure for
aquaculture and improve the resistance of these
components to the effects of stronger cyclones.
• Strengthen national capacity and regional
networks to adopt and implement aquatic biosecurity measures, including capacity for
monitoring, detection and reporting aquatic
animal diseases, using international protocols (OIE
2010), to prevent introduction of new pathogens.
Diversify the aquaculture sector
• Maintain a watching brief on advances in
aquaculture technologies in other regions to
identify opportunities to diversify the sector in
ways with potential to perform well under the
changing climate (e.g. marine microalgae for
biodiesel).
• Consider transfer of such technologies, with the
necessary biosecurity precautions, to increase the
resilience of the sector.
Fishmeal
• Reduce dependence on fishmeal (tilapia, carp,
milkfish, shrimp, freshwater prawns, marine
finfish) by: (1) progressively replacing fishmeal
with suitable local alternative sources of protein;
and (2) promoting Best Management Practice
(BMP) for feeding of farmed fish to increase feed
efficiency.
Carbon sinks
• Promote aquaculture systems that are carbon
sinks, like seaweed farming or pearls and edible
molluscs.
• Obtain official recognition of carbon capture by
such systems and then target the seafood industry
to purchase carbon offsets for such initiatives.
• Pursue investment in carbon offset schemes that
enhance the resilience of the coastal habitats on
which aquaculture ultimately depends, such as
mangrove planting and wetland conservation.
Aquaculture statistics
• A uniform system for collection of data on the
volumes of production, value, number of farms,
number and gender-balance of people employed,
exports vs. domestic, etc., is essential not only for
planning the development of the sector, but also
for monitoring the effectiveness of adaptations to
assist producers to optimise the opportunities
presented by climate change, and minimize the
adverse effects.
May fish be with you!