Global Implications of ENSO Events on Inland Fisheries

Ian G. Cowx

INSERT PHOTOS

HERE

INSERT PHOTOS

HERE

IFM, York, 21 May 2109

UNIVERSITY OF

Hull International Fisheries Institute

HIFI

Outline

• Where are we with research on extreme climate events.

• Impacts of extreme events on inland fisheries– Case studies: UK, African

Great Lakes, Mekong • Adaptation strategies and

increasing resilience

Winter

Summer

Current emphasis on climate research

Temperature and precipitation to 2050 (IPCC 2007)

IPCC predictions for inland areas are increased temperatures and regional variation in precipitation

Current emphasis on climate research

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Marine Inland

Expanding research focussing on marine environment and changes in distribution and phenology of species

Are we missing the impacts of extreme events – especially those driven by natural processes, e.g. ENSO?

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Marine Inland

Enso eventsDisruption of upwelling events arising from southern oscillations

1972-73 1982-83 1997-98 2015-16

el Niño events

el Niño events – marine environment

el Niño – freshwater environment

1974-76 1988-90 1998-2000 2016-18

el Niño v la Niña

la Niña – freshwater environment

River Rivelin, UK – July 18

Extreme climate events

Extreme events shape ecosystems

From Webb

UK floods and droughts

River Dibb, UK – April 18

River Dibb, UK – July 18

UK – July 17

UK – July 18

River Ouse, Yorkshire UK – July 07

2015 winter floods - YorkshireBoxing Day floods some of the most severe on record

2015 winter floods - Yorkshiree.g. River Washburn

2015 – pre flood 2016 – post 1 in 100 year flood

2015 Winter floods – River Washburn

0+ brown trout

1+ brown trout

Similar response to trout populations across north of England – washout of spawning redds

African Great Lakes – fisheries yield

Prediction: Fisheries yield (kg/ha) dependent on seasonal relative lake level (Source Kolding et al. 2012)

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Malawi

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Lake level variability and el Niño

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Nile perch Dagaa Tilapias Haplochromines Others

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Water level variation in Lake VictoriaVictoria

Lake Victoria - la Niña periodVictoria – Mara wetland

Fisheries of the lower Mekong Basin

ðEstimated 2.5 million t/yr

ð200+ species; 30+ of high commercial importance

ð > 40% of total fish catch in LMB (about 1.3 million tonnes worth US$6 billion) dependent on migratory fish

ð Fish production dependent on fish migration (all seasons of year) and extent of flooding

Drivers of fish productionWater level and flooding• Water level and extent of

flooding key drivers of fish production

• Shifts in fisheries productivity due to changes in hydrological patterns

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meanannual

Annual Delta fishery

y = 47575x - 15010R² = 0.5366

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Catch rate

Water Level

Daily catch driven by water level in delta

Climate changePredicted effects of climate change in Lower Mekong Basin

Temperature Precipitation

Predicted alteration of flood cycleo Potential greater rainfall

in monsoon season in Viet Nam Highlands altering flooding magnitude, duration and extent in LMB

o More extreme flooding cycle.

o 3-10% increase in wet season flows

o 2-6% reduction in dry season flows

Predicted change in fish yield (t)

Mekong delta + 65,000Cambodian floodplain

+ 44,300

Tonle Sap + 30,200Total change + 139,500

Climate change – fish productionPredicted shift in daily discharge at Prek Kdam---- baseline---- Climate change scenario

= +10% increase in fish production

Lower Mekong Basin 2015 El NiñoAnnual water level in Tonle Sap, Cambodia –red indicates severe el Niño years

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Water level in Viet Nam Delta

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Floo

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Biomass (Tonnes) Flood index

Severe reduction in flood peak and durationTonle Sap dai fishery closed early in November (2015) rather than February/March

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Tonle Sap 2015 El Niño

Exposure Sensitivity

Potential ecological impact

Recovery potential

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Resource dependency

Potential social impact

Adaptive capacity

Social- Ecological Vulnerability

Ecological Vulnerability

Feedbacks

Ecological

Socio-economic

Adaptation strategies

Adaptation: A process that aims to generate resilience to external stressors (related to resource dependence) and capacity to use potential opportunities in a sustainable and ethical manner

UK adaptation to floods and droughts

FloodsDredging: improved discharge capacity of riversNatural flood risk management: tree planting, reconnecting floodplains and buffer zones

DroughtsFlow Regulation: reduced compensation flows and regulate abstractionHabitat restoration – narrowing channels

Based on household surveys

• Shift in livelihoods of fishing communities towards employment such as construction [but not agriculture]

• Shift is diets: Fish and OAAs contribute about 70% of animal protein intake but drops to 54%

• Fish farming as non-equitable solution• Diplomatic engagement with China to

release water from upstream dams

Adaptation strategies - Mekong

This project receives funding from the European Union’s Horizon 2020 research and innovation programme under grant

agreement No 678193.

CERESClimate change and European aquatic

RESources

Ian Cowx

IFM, York 21 May 2019

Hull International Fisheries Institute

CERESPROJECT.EU