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Projected changes to freshwater fish habitats and stocks

Projected changes to freshwater fish habitats and stocks. Based on. Outline. Importance of flow Connectivity of freshwater habitats Effects of climate change Habitats Fisheries production Importance of catchment management. Freshwater fisheries in the region. Catch 24,000 tonnes per year

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Projected changes to freshwater fish habitats and stocks

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  1. Projected changes to freshwater fish habitats and stocks

  2. Based on.......

  3. Outline • Importance of flow • Connectivity of freshwater habitats • Effects of climate change • Habitats • Fisheries production • Importance of catchment management

  4. Freshwater fisheries in the region • Catch 24,000 tonnes per year • 4% of GDP derived from fisheries • Consumption up to 100 kg per year Photo Jacob Wani

  5. Diversity of freshwater habitats

  6. Flow – the Maestro

  7. Flow responses to rainfall Daily flow, Nabukavesi Creek, Fiji Episodic flow, Tontouta River, New Caledonia Seasonal flow, Ba River, Fiji

  8. Range of freshwater habitats

  9. Climate change effects

  10. Effects on freshwater are different! • Climate change will affect the quantity of freshwater habitat available to fisheries • Changes in water quality and habitat quality will be secondary to changes in flow

  11. Effects of altered rainfall

  12. Temperature and CO2 Photo: David Boseto • Increasing CO2 will promote growth of aquatic and riparian vegetation

  13. Sea level • Barriers (waterfalls, weirs, culverts) may block retreat of freshwater habitats

  14. Projected habitat changes

  15. Interactions in disturbed catchments Source: Google Earth

  16. Effects on fisheries Photo: Erin Michelle Smith

  17. Projected fisheries changes

  18. Adaptation recommendations • Maintain vegetation in catchments to avoid sediments and nutrients entering waterways Photo: Joanna Ellison

  19. Adaptation recommendations • Build capacity of local communities to manage habitats and fisheries resources Photo: Joanna Ellison

  20. Adaptation recommendations • Adopt more efficient fishing methods and limit fishing effort Photo: Boga Figa Photo: Boga Figa

  21. Adaptation recommendations • Manage threats from invasive species Photo: Boga Figa

  22. Adaptation recommendations • Monitor catches and measure the success of management interventions Photo: Jacob Wani

  23. Putting climate change in perspective ‘In tropical systems it is possible that the effects of global climate change will be overshadowed by other, larger disturbances such as deforestation and land-use changes.’ (Ficke et al. 2007) Photo: Jacob Wani

  24. Summary • Increased rainfall will increase freshwater habitats in tropical regions, less in subtropics • Freshwater fish production may increase by 5-10% • Disturbed catchments restrict production • Ridge to reef management is needed to maximise positive outcomes and minimise negative effects

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