Challenges in conserving critically-
endangered Freshwater Pearl Mussels;
advances over 10 years
Dr Ceri Gibson and Pearl Mussel team [email protected]
www.fba.org.uk
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1. Males release sperm which is inhaled by females.
2. Embryos develop into glochidia, which are released into the water.
3. Glochidia must encounter and attach to a suitable host fish for ~10months.
4. Mussels release from gills and burrow in the sediment.
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FPM LifecycleJuly / Aug
May / June
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Habitat requirements
Pristine water qualityStable clean gravelsPedal feeding juveniles dwell in interstitial sites
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Windermere
235km2 catchment
14.76km2 Lake
40.3m above sea level
• FPM wiped out of Leven in 19th
Century• 9 records for Brathay• Over 100 Brathay juveniles in
Ark
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FBA Ark timeline
2006• Concept of an Ark at FBA
2007
• Ark installed at Mitchell Wyke
• First adult mussels arrive on 18th April
2008• First successful excystment
2009
• Filters required to manage water supply efficiently
• Funded by Natural England & Environment Agency
...
• More adult mussels received
• Varying conditions / improved understanding
2015• Wider river improvement project starts
2017• Juveniles reintroduced to native rivers
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Regular cleaning / observation of tanks and trays
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Manipulating host fish
Essential to prevent salmon from smolting before glochidia excyst
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Windermere Reed beds
1902
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Windermere Reedbeds
1980
2001
Grassholme Island
Declining reed beds indicate changing water quality
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Windermere Surface Temperature –anomalies from 1961-90 mean
Period used to calculate IPCC mean
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First reintroduction - Still learning
Importance of local currents and sheer stress
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First reintroduction - Still learning
7cm
Herculean effort upstream and vertically up. Why?
Conclusions after 10 years
FBA breeding programme has shown considerable success
Improved understanding of the Ark system and mussels
Identification of suitable species of host fish
Application of WFD status is not ambitious enough for pearl
mussels
CEN standard agreed across 28 European countries which
underwrites the quality of water environment required for
protection of and successful reproduction of FPM
Currently we have not found any ideal sites for pearl mussel
reintroductions in the rivers examined
Engagement with all parts of the community is invaluable
Managing research and landscape-scale improvement with
annualised funding is a challenge!
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www.fba.org.uk
Thank you for listening
Any Questions?