Projected changes to aquaculture

Based on…….

Outline

•Freshwater aquaculture (tilapia, milkfish, freshwater prawn)

•Vulnerability of freshwater aquaculture

•Coastal aquaculture/mariculture (giant clams, corals, trochus, sea cucumbers)

•Vulnerability of coastal aquaculture

• Lake restocking to replace Mossambique Tilapia with Nile Tilapia

• PNG 10-15,000 households with tilapia farms

TilapiaFood security

• Cage culture

• Semi-intensive ponds

• Aquaponics

• PNG - 10-15,000 households with tilapia farms

TilapiaLivelihoods

Tilapia•T

ilapia farming is expanding in the region

•Samoa has 35 farms

•Fiji produces 200-300 tonnes per year

•Solomon Islands has begun an Inland Aquaculture project to support emerging farmers

•A tilapia hatchery has been established in Vanuatu

Milkfish

Freshwater ponds Cage culture for food, tuna-bait

Brackish ponds

• 30 – 80 t per year in Guam• 5 – 15 t per year in Kiribati• Four farms in Palau• Capture-based culture trials in Fiji,

Solomon Islands and Tonga

• Hatchery-based culture Hatchery-based culture ((M. rosenbergii)

• Capture-based culture Capture-based culture ((M. lar)

Freshwater prawn Macrobrachium

• Fiji produces about 25 t per year

Vulnerability of freshwater aquaculture

Tilapia, freshwater prawn

•Likely to benefit from climate change

• Higher rainfall and warmer temperatures will allow farming in more places and at higher altitudes.

•Some areas with increased rainfall or cyclones may become more prone to flooding

DFF (Fiji) Ltd freshwater prawn Farm

Cyclone Mick, December 2009

Tilapia, freshwater prawn

•Stratification from higher temperatures causes de-oxygenation – aeration needed

Tilapia, freshwater prawn

Milkfish

•Increased temperatures will extend the geographical range and season of fry collection

•Risk from ocean acidification?

How should we respond?

•Build fish ponds to avoid more severe floods

Photo: Avinash Singh

How should we respond?

•Increase aeration to combat stratification

Conclusion•F

reshwater pond aquaculture is likely to be favoured by climate change

Source: Pickering et al. (2011)

Coastal aquaculture

Annual value

•Pearl and shrimp farming dominate

•Comprise >90% of total value

Livelihoods

Shrimp

Pearl

Sea cucumber

Giant clam Trochus Green snail

Restocking

Vulnerability of mariculture

Marine fish, shellfish•M

ariculture of fish and shellfish faces major uncertainties

•Possible effects of acidification on larval fish and shells Applies to giant clams and cultured corals

Aquatic animal diseases

•Higher temperature are likely to increase prevalence of pathogens

•The nature and extent of future disease risks are not clear White Spot Virus WSV

Adaptations

•Grow ornamentals at greater depth (cooler waters)

•Identify sites where CO2 is reduced

•Selective breeding for resilience to acidification

See Chapter 11 for vulnerability of pearl oysters, shrimp, seaweed

and other commodities

Conclusion• Mariculture has development potential in years ahead

• But production efficiency is likely to be progressively affected by climate change