Projected changes to coastal aquaculture Presented by Timothy

Projected changes to coastal aquaculture Presented by Timothy Pickering

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

• 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

Current and projected mariculture production

Pearls

Marine shrimp

Seaweed (Kappaphycus)

Marine finfish Batfish (P. orbicularis) Barramundi Grouper (Serranidae)

Other species Mud crab Edible Oysters

Culture-based fisheries: restocking Sea cucumber Giant clam Trochus Green snail

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, >90% of total value Annual value of aquaculture commodity production

Livelihoods Shrimp Pearl

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

Projected production • Without considering the effects of cliamte change, aquaculture production is optimistically forecast 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‘

Vulnerability of mariculture

Projected climate change Source: Lough et al. (2011), Ganachaud et al. (2011)

Ocean acidification Source: IPCC (2007), Ganachaud et al. (2011)

Temperature 2035 2050* Spatial variation in temperature increase 2035 * Based on B 1 2100 Source: Lough et al. (2011)

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

Acidification and pearls If projected changes in seawater p. H adversely affect pearl oyster spat and adults, or pearl quality, then industry will be highly vulnerable High-quality Fiji Pearls Poor lustre, defects

Pearl farming Hunter Pearls hatchery, Fiji Islands • Vulnerable to cyclones but may benefit from sea-level rise Storm surge during Cyclone Tomas, February 2010

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

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

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

Kappaphycus seaweed • Seaweed is vulnerable to seawater temperature >30 o. C Ice-ice • Reduced salinity due to more rainfall stresses seaweed • Cause “ice-ice” and Epiphytic Filamentous Algae (EFA) outbreaks • Reduced nutrient supply will slow growth EFA

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

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

Summary of vulnerability

Summary of vulnerability

Key responses and adaptations

How should we adapt? • Expect production losses from extreme events and ‘unexpected’ causes • Ensure that financial planning for enterprises can absorb such shocks

How should we adapt? • Grow pearls at greater depth for final nacre Photo: Leanne Hunter Source: Pickering et al. (2011)

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

How should we adapt? • Build new shrimp ponds where drainage will not be affected by sea level rise

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

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)

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

Outlook for mariculture

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

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

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

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

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