Water quality requirement of lampreys

Lamprey are recognised as being sensitive to water pollution (Maitland, 2003) and compromised water quality. The larvae of all three species are rarely found in areas of stagnant water or eutrophic conditions; in addition heavy siltation and slow currents have been noted as unfavourable for larval lampreys (Kelly and King, 2001). Pollution events can have major impacts on all lamprey species by smothering both spawning gravels and nursery silts (Maitland, 2003). When instream works are undertaken during the lamprey spawning season (March to July), similar effects can occur as would occur if such works were undertaken during the salmonid spawning season (October to May). On Natura 2000 rivers designated for lampreys particular instream works should only take place during August and September, taking cognisance of the existing close seaosn for salmonids.

Eutrophication which is associated with lush growths of algae and bacteria associated with increased nutrients can also smother spawning gravels preventing spawning or killing eggs and creating anoxic conditions in nursery silts (Maitland, 2003).

The distribution of larvae is rarely affected by short-term low oxygen levels, as ammocoetes can tolerate low oxygen levels due to their low metabolic activity, their blood characteristics and branchial pumping ability (Maitland, 2003). The contributory factors leading to low oxygen levels, such as pollution and high temperatures, are more lethal to ammocoetes. Conversely adult lamprey do not have the same buffering with regard to oxygenation and adult Sea lampreys are known to have the same oxygen consumption as salmonids of comparable weight at various temperatures.

Although there is an apparent absence of legislation in relation to the avoidance of instream works during the lamprey spawning seaosn in Ireland, prosecutions are possible under European legislation and also the European Communities (Environmental Liability) Regulations 2008

Water temperature is an important regulatory factor for all three species of lamprey as it determines the onset of spawning and migration. The transformation of the larval stage to the macrophthalmia stage occurs over a very short period of three to four weeks and temperature may also be an influencing factor at this stage of development. Any developments directly or indirectly affecting the temperature within a river system must take consideration of the ecological requirements of lamprey species present.

Legislation

The key parameters in relation to water quality are set out in the European Communities Environmental Objective (Surface Waters) Regulations (2009 and Amendment Regulations 2012). However, there are no specific limits provided in these regulations for suspended solids, most often arising from the mobilisation of silt. Suspended solids are identified as a significant impact affecting both water quality and lamprey species directly and also indirect with siltation effectively blanketing spawning gravels and ova. The European Commission (Quality of Salmonid Waters) Regulations 1988 sets an annual average of ≤25mg/l for suspended solids in salmonid watercourses, this is considered an appropriate standard for lamprey with regard to the adult life stage and spawning requirements, where fluctuations may occur within this range. The primary legislation in the Irish context is therefore:

• S.I. No. 327 of 2012 European Communities Environmental Objectives (Surface Waters) (Amendment) Regulations 2012
• S.I. No. 272 of 2009 European Communities Environmental Objectives (Surface Waters) Regulations 2009
• E.C. (Quality of Salmonid Waters) Regulations 1988 (S.I. No. 293 of 1988)
• S.I. No. 547/2008 – European Communities (Environmental Liability) Regulations 2008

Guidance

The requirement with regard to the protection of watercourses during instream works are set out in guidance which includes details of the primary pollution control measures to be employed when working near water. These publications, in addition to the guidelines set out by the National Roads Authority are the principle guidance for instream works in Ireland. Instream works should never be undertaken during the lamprey spawning season, especially in Natura 2000 rivers. Although there is an absence of legislation in relation to this issue in Ireland, prosecutions are possible under European legislation and also the European Communities (Environmental Liability) Regulations 2008. There it would be advisable to take this issue into account when working in rivers, and schedule works outside sensitive times. For more information see ECOFACT (2012).  It is noted that this would also apply to state agencies.

• ECOFACT (2012) Ecology Survey and Mitigation Calendar. ECOFACT Environmental Consultants Ltd. Limerick, Ireland 
• Murphy, D (2004) Requirements for the Protection of Fisheries Habitat during Construction and Development Works at River Sites. Fisheries Protection Guidelines. Eastern Regional Fisheries Board, Dublin
• Kilfeather, P.K. (2007) Maintenance and protection of the Inland Fisheries resource during road construction and improvement works. Requirements of the Southern Regional Fisheries Board. Southern Regional Fisheries Board, Clonmel, Co. Tipperary.
• NRA (2008) Guidelines for the crossing of watercourses during the construction of National Road Schemes. National Roads Authority, Dublin

In Northern Ireland the Lough’s Agency have published guidance for the protection of water quality and fisheries, which, in addition to guidance published by the Northern Ireland Environment Agency; UK guidance published by the Scottish Environment Protection Agency and CIRIA guidance provides significant water quality protection measures for instream works which should be followed, taking specific regard to the differing requirements of Lamprey over salmonids.

• Loughs Agency (unknown) Guidelines for Fisheries Protection during Development Works (Foyle and Carlingford areas). Environmental Guidelines Series – No. 1.
• NIEA (2012) Road Schemes and the Protection of the Water Environment: A Water Management Unit Guidance Note. Northern Ireland Environment Agency, Department of the Environment Northern Ireland.
• SEPA (2010) Engineering in the Water Environment Good Practice Guide: River Crossings (2nd Edition). Scottish Environment Protection Agency.
• SEPA (2009) Engineering in the Water Environment Good Practice Guide: Temporary Construction Methods. Scottish Environment Protection Agency.
• Murnane, E., Heap, A., and Swain, A. (2006) Control of water pollution from linear construction projects. Technical guidance: C648. CIRIA, London, UK
• Design Manual for Roads and Bridges (2006) Surface and Sub-Surface Drainage Systems for Highways Vol. 4 Geotechnics and Drainage: Section 2 Drainage – Part 3 HD 33/06
• Design Manual for Roads and Bridges (2009) Vol. 11 Environmental Assessment – Section 2 Environmental Assessment Techniques. Part 10 HD 45/09.

General references

• Maitland P.S. (2003) Ecology of river, brook and sea lamprey. Conserving Natura 2000 Rivers Ecology Series No. 4. English Nature, Peterborough.
• Kelly, F.L. and King, J.J. (2001) A review of the ecology and distribution of three lamprey species, Lampetra fluviatilis (L.), Lampetra planeri (Bloch) and Petromyzon marinus (L.): A context for conservation and biodiversity considerations in Ireland. Biology and Environment: Proceedings of the Royal Irish Academy 101B (3), 165_/85.