potential impacts of climate change on piharau/kanakana ... · •need to address larval stage...
TRANSCRIPT
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Potential impacts of climate change on piharau/kanakana populationsCindy Baker, Jane Kitson, Allison Miller & Neil Gemmell
Outline• Piharau/kanakana biology• Impacts predicted from climate
change: • What do we know from
current research • What can we learn from
overseas species• What are the key knowledge
gaps
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A Living fossil
Adapted from Columbia River Inter-tribal Fish Commission
Spawning
Young Adult (450-750 mm)
Feeding on other fish and whales
Mature Adult (350-570 mm) Larvae (8-120 mm)
(ammocoetes)
Juvenile (100-120 mm)(macropthalmia)
Freshwater
Ocean
The lifecycle of piharau/kanakana
Rod Morris
Rod Morris
3-4 yrs1.5 yrs
3-4 yrs
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Current status of lamprey
• Lack of quantitative data• Stronghold in
Southland/Otago• Abundance declines with
distance north• Still good populations in
Canterbury and potentially the greater Wellington region• Key North Island rivers still
fished suggest serious decline (e.g. Mokau River, Whanganui River, rivers in the Taranaki region)
0 300 km
N
Key threats to piharau/kanakana populations
• Barriers to passage
• Habitat loss/alteration (e.g. land use change, channel maintenance)
• Water quality (e.g. temperature, dissolved oxygen, pH, ammonia, nitrate)
• Pollution (e.g. heavy metals, PAHs, PCBs)
• Predation (e.g. shags, tuna, trout, seals)
• Lamprey Reddening Syndrome
• Climate Change
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Increasing atmospheric CO2
concentration + other greenhouse gases
Effects on physiology
Climate Change• Increasing global mean temperature• Changes in patterns of precipitations• Changes in the frequency and severity of extreme
events
Changes in community structure and composition
Changes in species interactions
Effects on life cycle Effects on distributions Adaption in situ
Further shifts in distribution
Extinction of some species
Hughes 2000
Temp Annual Change 1995-2090 (oC) Precipitation Annual Change 1995-2090 (%)
MfE 2018 Climate Change Projections for NZ
• Further stress on North Island populations
• Pacific lamprey distribution already moving North (colder areas)
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Larval populations resident in streams and rivers
• Little information on larval piharau/kanakana in NZ• 28.3⁰C lethal temperature
piharau/kanakana larvae• Water temperatures >22-23⁰C
increase egg & larval mortality • Pacific lamprey larvae held at 22.5⁰C
has a metabolic rate 4x higher than those held at 13⁰C. Resulted in reduced length and fish halving in weight
Larval populations resident in streams and rivers
• Impacts on larvae from changes in water quality unknown• Impacts from increased water
abstraction pressures likely• Other impacts from land-use changes
and extreme weather events• Know very little about what impacts
larval growth and survival• A ‘black box’ for NZ
Age Photostock
54 larvae/m2 6 larvae/m2
2016 2018
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Migration cue for adult stream selection• Larval populations are thought one of the most important factors for drawing adults into
rivers
Find the pēpi
Up here!
• Nine sites (2015 – 2018)• Piharau/kanakana larvae sampled• Single-gene sequencing (Cytb)• Reduced representation genome
sampling – next generation sequencing (NGS)
Genetic analyses to examine adult migration and mixing in the ocean
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Genetic analyses to examine adult migration and mixing in the ocean• Results suggests a single
population for all New Zealand lamprey
• Single-gene sequencing (Cytb gene): suggests no genetic difference between individuals
• It is likely that lamprey from Te Ika-a-Māui and Te Waipounamu mix
Dim1 (1.2%)
Dim
2 (1
.1%
)
Why are adult piharau/kanakana unevenly
distributed between islands?
• A working hypothesis – larvae are less abundant in the North Island • Less migration cue = less adults• Climate change likely to
increase pressure on North Island larvae
0 300 km
N
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Potential impacts of climate change on adult piharau/kanakana
• Oceanic life stage another ‘black box’• Impacts of ocean acidification?• Changes in host species utilised?• Changes in host species distributions
and migration patterns?• Increased metabolic rate of adults –
larger piharau/kanakana. More impact on host?• Too little information is known to
determine impacts
J. Harbord
McDowall 1990
Where to from here?• Temperature
increases inevitable• Where possible
restoring rivers to near natural state (e.g. remove barriers, improve shading/vegetation water quality)
ü
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Where to from here?
• Current MBIE programme has 2 years to run• Continuing to
understand the spawning habitat and requirements of adult piharau/kanakana• “Love lofts” as artificial
spawning substrates
Where to from here?
• Understanding their climbing behavior and how best to create passage structures for getting adult piharau/kanakana past instream obstacles
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Where to from here?• Need to address
larval stage knowledge gaps• Artificial
propagation carried out for Pacific lamprey • Aim is to translocate
and enhance wild populations
Conclusions• Climate change likely to stress
piharau/kanakana populations, particularly in the North Island• Little is known about what impacts
larval growth and survival - a key knowledge gap for predicting climate change impacts • Internationally restoration activities
focus on:• Returning rivers to “natural state” (e.g.
removing barriers & revegetation) in preparation for temperature and flow changes
• Artificial propagation
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Piharau/kanakana are resilient!Climate change is a tiny piece of their 450+ million year existence
Adapted from Columbia River Inter-tribal Fish Commission
Acknowledgements
• Tangata whenua Marcus Tuwairua, Jeremy & Vincent Leith, Calvin Russell, Riki Parata, Stevie Blair, Steph Blair, Moana Grey, Aaron Leith, Dawn Wybrow, Gail Thompson, Tony Leith, Pani Finch, Sandy Young, Peter Stockman
• Zane Moss (Fish and Game)• Funded by Ministry of Business,
Innovation and Employment (MBIE) contract C01X1615 Habitat Bottlenecks
• NIWA staff Peter Williams, Emily White, Nicola Pyper, Kathryn Reeve
