Control of Aquatic Invasive Species and Restoration of Natural Communities in Ireland

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Control of Aquatic Invasive Species and
Restoration of Natural Communities in Ireland
Dr Joe Caffrey Central Fisheries Board
QUB, Belfast 7th April 2009
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Scope
High impact aquatic invasive species in Ireland
Case study Lagarosiphon major (Curly Waterweed)
Future work and funding
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High Impact Aquatic Invasive Species
Curly Waterweed Lagarosiphon major Nuttalls
Waterweed Elodea nuttallii Dace Leuciscus
leuciscus Zebra Mussel Dreissena polymorpha
New Zealand Pigmyweed Crassula helmsii Parrot
Feather Myriophyllum aquaticum Fringed Water
lily Nymphoides peltata Water Fern Azolla
filiculoides
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Potentially High Impact Aquatic Invasive Species
Chinese Mitten Crab Eriocheir sinensis Chub L
euciscus cephalus Bloody Red Shrimp Hemimysis
anomala Floating Pennywort Hydrocotyle
ranunculoides
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Lagarosiphon near Kilmeaden, Waterford 2005
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Nuttalls Waterweed (Elodea nuttallii) in
Carrigadrohid Reservoir
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New Zealand Pigmyweed (Crassula helmsii)
Emergent and submerged
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Parrots Feather (Myriophyllum aquaticum)
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Fringed Water lily (Nymphoides peltata)
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Water Fern (Azolla filiculoides)
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Azolla in River Barrow and Limerick Canal
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Chinese Mitten Crab (Eriocheir sinensis) - 2005
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Chub (Leuciscus leuciscus), River Inny 2006
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Bloody Red Shrimp (Hemimysis anomala)
Photo - Dan Minchin (2008)
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Floating Pennywort (Hydrocotyle ranunculoides)
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INVASIVE SPECIES CONTROL
Case Study Lagarosiphon major in Lough Corrib
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Curly Waterweed (Lagarosiphon major)
Submerged aquatic Oxygenating weed Artificial
watercourses Only natural habitat is Lough
Corrib
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Rinerroon Bay, Lough Corrib pre-Lagarosiphon
major
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Rinerroon Bay, Lough Corrib post-Lagarosiphon
major (2005)
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Why is Lagarosiphon a Problem?

• No natural enemies in Ireland
• Rapid growth rate
• Dispersal through fragmentation
• Actively grows in winter
• Canopy forming excludes indigenous macrophytes
• Alters macroinvertebrate community structure
• Creates improved conditions for coarse fish
• No legislation to prohibit its sale and
  distribution

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Lagarosiphon Control Methods Currently Employed

• Hand removal using Scuba
• Mechanical cutting and harvesting
• Herbicides
• Light exclusion
• Life cycle studies
• Biological control

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Hand Removal using Scuba
Lagarosiphon in low abundance - recently
colonised sites - edge of large stands -
following other treatment methods
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Herbicides for Lagarosiphon Control
Lough Corrib is a SAC and drinking water supply
!!!

• Only one approved herbicide to treat submerged
  weeds
• Lagarosiphon is susceptible to dichlobenil
• Applied locally in upper lake

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Mechanical Cutting in Lough Corrib

• Deep cut with trailing knives (V-blades)
• 10 infested sites treated in 2008
• 4,700 tonnes of Lagarosiphon removed
• 29.2 hectares of infested lake bed cleared

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Light Exclusion using Biodegradable Geotextile -
2008

• Trials commenced in August 2008
• 1,750 sq m at 4 sites treated
• Early indications positive

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Life Cycle Studies as an Aid to Lagarosiphon
Control
Little is known about the life cycle strategies
or adventive traits of Lagarosiphon under Irish
conditions
Less is known about the factors that influence
its growth in Irish waters
This information is vital if potential weak links
in Lagarosiphons life cycle are to be identified
and targeted for specific control
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Restoration of Natural Communities
Natural recolonisation of indigenous species from
spores, seeds, fragments Transplant indigenous
species Create conditions favourable for
indigenous species
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Funding Future Research

• Primary source of funding for 2009 - 2013 is
  Life (EU NPWS)
• 1.5 million
• 2 Projects Lagarosiphon control in Lough
  Corrib Invasive species in Grand Canal /
  Barrow corridor
• Worth approx. 180k per annum per project (vs
  c. 200k for 6 months on Lagarosiphon in 2008)

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Strategic Control of Lagarosiphon in 2009
Clearance of sites from all upstream sites
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Strategic Control of Lagarosiphon in 2009
Mechanical cutting of sites on north-western shore
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Strategic Control of Lagarosiphon in 2009
Apply geotextile to all sites in the middle lake
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Road Map for Lagarosiphon Control in Lough Corrib
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Road Map for Lagarosiphon Control in Lough Corrib
Biocontrol

• PhD to be funded commencing in summer 2009
• Collaboration with University of Grahamstown in
  SA
• No. of candidate species already identified

Photos J-R Baars
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Can We Eradicate Lagarosiphon in Lough Corrib?
Enormous task using traditional methods Best
expertise available will be utilised
Biocontrol may provide the silver bullet