Flowing Water Lecture 7

Overview of Freshwater Fish Regulatory Framework

• Focus on the legislative measures related to freshwater fish in the UK

• Importance of understanding effectiveness and challenges in fish protection

Freshwater Fish & Regulation

• Freshwater fish populations are monitored under various legal frameworks to ensure protection and sustainability.

• Recent data indicates a major fish kill incident in the UK involving over 1000 fish, raising questions about the efficacy of freshwater legislation.

Key Legislation

EU/UK Water Framework Directive

• Aims to protect aquatic ecosystems and ensures good water quality standards.

• Enforces responsibilities on water companies to supply wholesome water sustainably.

UK Water Resources Act 1991 and Environment Act 1995

• Establishes the National Rivers Authority’s duties to manage sustainable abstraction and monitor environmental standards.

• Transitioned to the Environment Agency, which enforces standards in land and air pollution, flood defence, and water abstraction licensing.

Water Licensing System and Abstraction

Abstraction Sensitivity Bands (ASB)

• ASB 3 (High Sensitivity): Salmon rivers or chalk streams; target for stringent protection.

• ASB 2 (Moderate Sensitivity): Rivers vulnerable to siltation and with sensitive fish populations.

• ASB 1 (Low Sensitivity): Naturally silty rivers with low ecological sensitivity.

Challenges in Water Licensing

• Issues concerning fair application of licence capping affecting small landowners disproportionately while benefiting larger companies.

• farmers renewal date 6-18 years vs water companies 50+ years

• Monitoring of water flows remains a critical area requiring improved methodologies to assess actual water availability.

• water gauging not undertaken for all waterbodies

• increased water demand and climate warming - strain on whole systems

Fish Species Sensitivity to Abstraction

Low Tolerance Species

• Salmon (Salmo salar)

• Brown and Sea Trout (Salmo trutta)

• Grayling (Thymallus thymallus)

• Lampreys and Bullhead (Cottus gobio)

Medium Tolerance Species

• Includes species like Barbel, Pike, and various Loach types, indicating varying sensitivity to environmental conditions.

High Tolerance Species

• Consists of resilient species such as Carp, Tench, and Roach, which can survive in harsher water quality conditions.

Impact of Water Abstraction on Fish

• Unsustainable abstraction leads to reduced stream volumes (shallower) and habitats suitable for larger fish populations.

• Effects include lower stream velocities, increased sedimentation, and a detrimental impact on fish spawning habitats.

• fish eggs smothered by sediment build up

• diversity and abundance of macroinverts. lower on silty beds.

• Observations suggest fish vacate areas heavily affected by abstraction.

• fish easily predated by birds in low flows

Environmental Challenges and Pollution

Ammonia Toxicity

• High ammonia levels from treated sewage effluents harm aquatic life, leading to respiratory failure and even mortality.

• Poorly treated effluents also result in decreased dissolved oxygen levels, further stressing aquatic ecosystems.

Impacts of Eutrophication

• Increased organic pollution leads to algae blooms, reducing oxygen in waterways and disrupting fish habitats

• anoxic conditions - rapid bacterial growth

Issues Involving Invasive Non-native Species (INNS)

• Examples include small species like topmouth gudgeon and larger species like Wels catfish, which threaten native fish through predation and competition.

Water Quality Monitoring and Ecological Assessment

• Regular assessments required to monitor ecological status of water bodies according to the EU Water Framework Directive.

• Challenges include establishing expected ratios of species presence versus absence in various aquatic environments.

Summary and Future Directions

• Despite existing regulations, fish assemblages still fail to meet diversity and ecological quality targets.

• Ongoing reviews and improvements in regulations, monitoring techniques, and pollution control measures are essential for enhancing the ecological health of UK freshwater systems.