Control of Aquatic Invasive Species and Restoration of Natural

Communities in Ireland

Dr Joe Caffrey

Central Fisheries Board

QUB, Belfast – 7th April 2009

Scope

High impact aquatic invasive species in Ireland

Case study Lagarosiphon major (Curly Waterweed)

Future work and funding

High Impact Aquatic Invasive Species

Curly Waterweed Lagarosiphon major

Nuttall’s 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

Chinese Mitten Crab Eriocheir sinensis

Chub Leuciscus cephalus

Bloody Red Shrimp Hemimysis anomala

Floating Pennywort Hydrocotyle ranunculoides

Potentially High Impact Aquatic Invasive Species

Lagarosiphon near Kilmeaden, Waterford 2005

Nuttall’s Waterweed (Elodea nuttallii) in Carrigadrohid Reservoir

New Zealand Pigmyweed

(Crassula helmsii)

Emergent and submerged

Parrot’s Feather

(Myriophyllum aquaticum)

Fringed Water lily

(Nymphoides peltata)

Water Fern

(Azolla filiculoides)

Azolla in River Barrow and Limerick Canal

Chinese Mitten Crab (Eriocheir sinensis) - 2005

Chub (Leuciscus leuciscus), River Inny – 2006

Bloody Red Shrimp (Hemimysis anomala)

Photo - Dan Minchin (2008)

Floating Pennywort (Hydrocotyle ranunculoides)

Case Study

Lagarosiphon major in Lough Corrib

INVASIVE SPECIES CONTROL

Curly Waterweed (Lagarosiphon major)

Submerged aquatic

‘Oxygenating weed’

Artificial watercourses

~ Only natural habitat is Lough Corrib

Rinerroon Bay, Lough Corrib pre-Lagarosiphon major

Rinerroon Bay, Lough Corrib post-Lagarosiphon major (2005)

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

Lagarosiphon Control Methods Currently Employed

Hand removal using Scuba

Mechanical cutting and harvesting

Herbicides

Light exclusion

Life cycle studies

[Biological control]

Hand Removal using Scuba

Lagarosiphon in low abundance

- recently colonised sites

- edge of large stands

- following other treatment methods

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

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

Light Exclusion using Biodegradable Geotextile - 2008

Trials commenced in August 2008

1,750 sq m at 4 sites treated

Early indications positive

Little is known about the life cycle strategies or adventive traits of Lagarosiphon under Irish conditions

Life Cycle Studies as an Aid to Lagarosiphon Control

Less is known about the factors that influence its growth in Irish waters

This information is vital if potential weak links in Lagarosiphon’s life cycle are to be identified and targeted for specific control

Restoration of Natural Communities

Natural recolonisation of indigenous species from spores, seeds, fragments

Transplant indigenous species

Create conditions favourable for indigenous species

Funding & Future Research

Primary source of funding for 2009 - 2013 is Life+ (EU & NPWS)

€1.5 million

2 ProjectsLagarosiphon 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)

Strategic Control of Lagarosiphon in 2009

Clearance of sites from all upstream sites

Strategic Control of Lagarosiphon in 2009

Mechanical cutting of sites on north-western shore

Strategic Control of Lagarosiphon in 2009

Apply geotextile to all sites in the middle lake

Road Map for Lagarosiphon Control in Lough Corrib

2009 Q2

2009 Q3

2009 Q4

2010 Q1

2010 Q2

2010 Q3

2010 Q4

2011 Q1

2011 Q2

2011 Q3

2011 Q4

Recruit & Train

Review & Report

Review & Report

Literature review

Report Report

2012 Q1

2012 Q2

2012 Q3

2012 Q4

2013 Q1

Final Report

BiocontrolControlled Experiments in Corrib

Research

Monitoring Program

Monitoring Program

Education and awareness

Education and awareness

Implementation Eradication

Eradication

Experiments in QuarantineControlled Experiments under

licence

Biocontrol

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

Can We Eradicate Lagarosiphon in Lough Corrib?

Enormous task – using traditional methods

Best expertise available will be utilised

Biocontrol may provide the ‘silver bullet’