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Projected changes to freshwater fish stocks. Presented by Peter Gehrke. Key messages. Freshwater fisheries are important in Fiji!!! Increased rainfall will increase freshwater habitats in tropical regions, less in subtropics Freshwater fish production increase by 5 – 20%
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Projected changes to freshwater fish stocks Presented by Peter Gehrke
Key messages • Freshwater fisheries are important in Fiji!!! • Increased rainfall will increase freshwater habitats in tropical regions, less in subtropics • Freshwater fish production increase by 5 – 20% • Disturbed catchments restrict production • Five adaptations to maximise positive outcomes and minimise negative effects
Freshwater fisheries in Fiji • Fijian catch > 4,000 t/y, total 24,000 t/y • 3% of wild catch value • Dominated by invertebrates • Subsistence and commercial value • Part of culture and language
Effects of altered rainfall Freshwater fish catches typically correlated to river flows
Temperature • Sex ratios • Growth rates • Larvae feed earlier (starvation?) • Muscle development • Pollutants increase sensitivity (lower temp tolerance)
Sea level Barriers (waterfalls, weirs, culverts) may block retreat of freshwater fish and clams
Adaptation recommendations • Improve habitat management to reduce exposure and sensitivity to climate change
Adaptation recommendations • Build capacity of local communities to manage habitats and fisheries resources
Adaptation recommendations • Adopt more efficient fishing methods and limit fishing effort
Adaptation recommendations • Manage threats from invasive species
Adaptation recommendations • Monitor catches and measure the success of management interventions
In summary … The outcomes of climate change for Fiji’s freshwater fisheries will be determined by the effectiveness of strategies to minimise human impacts at the catchment scale.