Instream enhancement works in Ireland – what about lampreys?

After decades spent destroying thousands of kilometres of river channels in Ireland, the Office of Public Works (OPW) has recently embarked on a river enhancement programme. This programme is being undertaken in collaboration with Inland Fisheries Ireland (IFI) and has set out to try to repair some of the damage that has been done to our river ecosystems by arterial drainage schemes and their maintenance. However, this work is almost exclusively targeted at salmonids, and other species such as lampreys are rarely considered. Indeed these so called enhancement works can in themselves cause significant ecological damage.

These works on the River Nanny in Tuam are also in breach of Objective RT29 of the Tuam Local Area Development Plan

The photos below show the River Nanny in Tuam, Co Galway. When we undertook a catchment-wide survey of juvenile lampreys in the Corrib catchment on behalf of the National Parks and Wildlife Service (NPWS) in 2006 (O’Connor, 2007), this stretch of river had one of the highest densities of brook lamprey in the entire Corrib system. However, it is was modified recently under one of these river “enhancement” programmes and apparently no consideration has been given to its status as an important brook lamprey habitat. Brook lampreys are listed under Annex II of the EU Habitats Directive, and their protection outside SACs would come under the provisions of the Environmental Liabilities Directive.

We visited this site last year and found that all the ammocoete nursery habitat in the town stretch is being infilled with rock and gravel, in works that will clearly only benefit salmonids. There is no evidence that juvenile lampreys were moved out of the way before this work was undertaken and it is likely that thousands of lamprey ammocoetes are being killed as their silt and mud nursery habitats are covered over with rocks and gravel. There will be a permanent loss of nursery habitat for this European Protected Species. OPW machines also dredged the river and apparently tracked over stands of the non-native invasive species Japanese Knotweed Fallopia japonica, with no evidence of appropriate biosecurity measures in place at this site.

Brook lampreys spend most of their life burrowed in silt and mud and many people (including OPW and IFI staff)   do not even know they are there.

Brook lampreys spend most of their life burrowed in silt and mud and many people (including OPW and IFI staff apparently) do not even know they are there. They are important components of healthy stream ecosystems however and are of significant biodiversity value. They are a European Protected Species and outside of SACs their protection will come under the provisions of the Environmental Liabilities Directive.

These works on the River Nanny in Tuam are also in breach of Objective RT29 of the Tuam Local Area Development Plan. This Objective states that “Any agencies undertaking river works in the future shall include measures to protect brook lampreys and their remaining habitats in the River Nanny as appropriate“. In our opinion no measures to protect the remaining brook lamprey nursery habitat are in place, and indeed all the lamprey nursery habitats are being destroyed.

the current enhancement works undertaken by the OPW will potentially cause the loss of an Annex II species from this part of the Corrib catchment

When the works are complete habitats here may also not be any better for juvenile salmonids – due to the low gradient. In our opinion this area was already of significant biodiversity value, was one of the most important sites for brook lampreys in the Corrib catchment, and these lampreys were protected by an Objective in the Tuam Local Area Plan (not to mention the EU Habitats Directive). The River Nanny is a tributary of the River Clare which is part of the Lough Corrib candidate Special Area for Conservation. Brook lampreys are a key conservation of this SAC and the state agency charged with their protection in Ireland is, in our opinion, failing to do their job. Without nursery habitats brook lampreys will not be able to survive in this part of the River Nanny and there is an impassable barrier for lampreys downstream from here so this is an isolated population. In our opinion it is not just OPW flood protection schemes that destroy lampreys habitats – these ‘river enhancement schemes’ are also damaging.

River-Nanny-Tuam

This was the affected stretch of the River Nanny before the current works and encroachment by car park and basketball court developments. Exceptional densities of juvenile brook lampreys were recorded here during a NPWS funded survey in 2006.

River Nanny, August 2006, prior to extensive instream works and encroachment of development in the town centre

River Nanny, August 2006, prior to extensive instream works and encroachment of development in the town centre (from O’Connor, 2007)

Brook lampreys from the River Nanny in Tuam, August 2006 (from O'Connor, 2007).

Brook lampreys from the River Nanny in Tuam, August 2006 (from O’Connor, 2007). The bottom individual is fully ‘transformed’ and both of these individuals were likely to have spawned the following spring.

This deflector was previously installed on top of lamprey nursery habitats   immediately downstream of the current works.

This deflector was previously installed on top of lamprey nursery habitats immediately downstream of the current works. There are no habitats for juvenile lampreys now left in the River Nanny within Tuam town. This is despite the fact that in 2006 this stretch of river had the highest densities of this species recorded in the entire Corrib catchment.

It is noted that the destruction of juvenile lamprey habitats on the River Nanny in Tuam follows on from a range of other impacts on this river corridor since we visited this site in 2006. Since that time a new bridge has been built over the river, and a road, car park and basket ball courts have been constructed along its banks. This has destroyed the riparian zone and is also in breach of the Tuam Local Area Development Plan (LADP).

Objective NH1 of the LADP sought to ensure “that a minimum setback of 10 metres is maintained in any new development proposals along the River Nanny and its tributaries“. In Tuam both the car park, road and Presentation College basketball courts have all encroached onto the river with no setback whatsoever provided for the latter. This is all in breach of Objective NH4 in the aforementioned plan which aimed to “Enhance biodiversity richness by protecting all rivers/streams and water bodies within the plan area by reserving riparian zones/ecological corridors, maintaining them free from inappropriate development“. In Tuam none of this has been achieved; the last semi-natural areas in the town have been paved over, the River Nanny has been degraded and the current enhancement works undertaken by the OPW and IFI will potentially cause the loss of an Annex II species from the area.

References

PS: We are campaigning for better treatment of lampreys in Ireland, along with a more holistic approach to river management. The state agency charged with protecting lampreys in Ireland does not, in our opinion, consider their requirements appropriately on projects like this. It is also clear that Inland Fisheries Ireland have failed to protect the riparian areas of the River Nanny from encroachment by development in recent years. It is appreciated that the car park development may have been unauthorised according to the media report entitled “New Supreme Court appeal likely in relation to Tuam car park controversy“. However why the Presentation College was allowed to build basketball courts right to the edge of the river is unexplained. It is also clear that overall there have been significant breaches of the Tuam Local Area Plan and this should be independently investigated. It also clear that river works like this should consider all of the species that live in a watercourse. The blanket infilling of our rivers with rocks and gravel as is happening at the moment in the name of conservation will, in the future, come to be viewed as being as damaging as the original arterial drainage schemes these works sought to reverse.

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