Projected changes to coastal aquaculture

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Projected changes to coastal aquaculture
Presented by Timothy Pickering
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Authors

• This presentation is based on Chapter 11
  Vulnerability of aquaculture in the tropical
  Pacific to climate change in the book
  Vulnerability of Tropical Pacific Fisheries and
  Aquaculture to Climate Change, edited by JD
  Bell, JE Johnson and AJ Hobday and published by
  SPC in 2011.
• The authors of Chapter 11 are Timothy Pickering,
  Ben Ponia, Cathy Hair, Paul Southgate, Elvira
  Poloczanska, Luc Della Patrona, Antoine
  Teitelbaum, Chadag Mohan, Michael Phillips,
  Johann Bell and Sena De Silva

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• Coastal aquaculture (mariculture) already makes a
  significant contribution to some Pacific
  economies
• It has unrealised potential in other PICTs
• But future plans could be derailed by projected
  climate changes

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Current and projected mariculture production
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Pearls
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Marine shrimp
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Seaweed (Kappaphycus)
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Marine finfish
Batfish (P. orbicularis)
Barramundi
Grouper (Serranidae)
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Other species
Mud crab
Edible Oysters
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Culture-based fisheries restocking
Sea cucumber
Giant clam
Trochus
Green snail
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Annual value of aquaculture

• Total value in 2007 was US 211 m
• Pearl farming in French Polynesia dominates
• Next is shrimp in New Caledonia
• Together, gt90 of total value

Annual value of aquaculture commodity production
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Livelihoods
Shrimp
Pearl
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Contribution of aquaculture to GDP

• Aquaculture provides 22 of fisheries
  contribution to GDP across the region

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Projected production

• Without considering the effects of cliamte
  change, aquaculture production is optimistically
  forecast to be to be worth USD 320 million by
  2025
• Growth mainly driven by expansion of existing
  commodities, and via adoption of these
  commodities by additional PICTs
• But note SPC report Opportunities for the
  Development of the Pacific Islands Mariculture
  Sector

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Vulnerability of mariculture
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Projected climate change
Source Lough et al. (2011), Ganachaud et al.
(2011)
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Ocean acidification
Source IPCC (2007), Ganachaud et al. (2011)
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Temperature
2035
2050
Spatial variation in temperature increase
2035
2100
Source Lough et al. (2011)
Based on B1 2100
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Projected impacts

• Mariculture faces major uncertainties
• Poor knowledge about effects of seawater
  acidification on shell formation
• Pearl aquaculture is more vulnerable to
  acidification than shrimp

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Acidification and pearls

• If projected changes in seawater pH adversely
  affect pearl oyster spat and adults, or pearl
  quality, then industry will be highly vulnerable

High-quality Fiji Pearls Poor lustre, defects
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Pearl farming
Hunter Pearls hatchery, Fiji Islands

• Vulnerable to cyclones but may benefit from
  sea-level rise

Storm surge during Cyclone Tomas, February 2010
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Shrimp farming
Now

• Industry faces both benefits and risks from
  climate change
• Climatic conditions for shrimp farming in
  subtropics are likely to improve, subject reduced
  temperature fluctuation

Future good
Future bad
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Shrimp farming

• The main threats to shrimp aquaculture stem from
• Acidification
• Sea-level rise
• Scarcity of fishmeal
• Pathogens

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Shrimp farming
Now crop in progress

• Sea-level rise will make ponds impossible to dry
  between crops

Now pond preparation
Future poor pond preparation
Future difficult to harvest
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Kappaphycus seaweed

• Seaweed is vulnerable to seawater temperature
  gt30oC
• Reduced salinity due to more rainfall stresses
  seaweed
• Cause ice-ice and Epiphytic Filamentous Algae
  (EFA) outbreaks
• Reduced nutrient supply will slow growth

Ice-ice
EFA
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Marine fish, shellfish

• Mariculture of fish and shellfish faces major
  uncertainties
• Possible effects of seawater acidification on
  larval fish
• and shells

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Aquatic animal diseases

• Higher temperatures caused increased prevalence
  of pathogens
• Nature and extent of future aquatic animal
  disease risks are not clear

White Spot Virus WSV
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Summary of vulnerability
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Summary of vulnerability
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Key responses and adaptations
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How should we adapt?

• Expect production losses from extreme events
  and unexpected causes
• Ensure that financial planning for enterprises
  can absorb such shocks

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How should we adapt?

• Grow pearls at greater depth for final nacre

Photo Leanne Hunter
Source Pickering et al. (2011)
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How should we adapt?

• Long term data collection to identify sites where
  conditions for nacre growth may be better
• Progressively switch to hatchery production

Photo Rusiate Vadiga
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How should we adapt?

• Build new shrimp ponds where drainage will not be
  affected by sea level rise

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How should we adapt?
Move shrimp ponds landward or to higher
ground Adopt more intensive farming methods
that use less land and water
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How should we adapt?

• Build up walls and floors of existing shrimp
  ponds

Suitable sediment for shrimp and meiofauna
Source Della Patrona et al. (2011)
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How should we adapt?

• Select sites for seaweed farms near upwelling
  areas and at low risk from increased freshwater
  runoff
• Use temperature- and salinity-tolerant strains to
  avoid ice-ice and EFA

Photo Gideon Tiroba
Photo George Steinmetz
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Outlook for mariculture
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Pearl farming

• Difficult to project production of pearls until
  more is known about effects of seawater
  acidification

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Shrimp farming

• New Caledonia could still double production (to
  4000 tonnes per year and 1000 livelihoods)
• Fiji could develop to 1000 tonnes in the medium
  term
• PNG could develop to 2000 tonnes
• But rofit margins will be lower

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Kappaphycus seaweed

• Medium-term targets of 1000 tonnes per year
  (engaging hundreds of households) for Fiji,
  Kiribati PNG and Solomon Islands , should still
  be achievable
• But not in the same places, by the same methods,
  or with the same varieties

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Other commodities

• Marine finfish, mud crab, corals, giant clam,
  trochus, and sea cucumber are fledgling
  industries

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Conclusion

• Mariculture has much scope for development
• Production efficiency is likely to be affected by
  climate change