All Wales Fisheries Monitoring Equipment Framework

Acoustically tagging fish allows detailed information to be gathered around fish behaviour and movements within the riverine environment, that can be used to prioritise actions and influence management of fisheries. Acoustic tagging allows detailed analysis of fish movements within river systems, through estuaries and in the marine environment. Tagging work has been ongoing on the river Dee for 5 years, but tagging projects are being expanded out across Wales. In addition, fish tagging will be a key monitoring activity for LIFEDeeRiver to understand impacts of improvement actions

Acoustically tagging fish allows detailed information to be gathered around fish behaviour and movements within the riverine, estuarine and marine environments that can be used to prioritise actions and influence management of fisheries.

Tagging technology has been used by fisheries scientists and managers in numerous studies - including investigation of migratory behaviour at fine and large scale, and enumeration of population size and related processes.

NRW has identified opportunities to apply this tagging technology to gather information on the temporal and spatial distribution and behaviour of migratory fish behaviour during both the freshwater and marine stages of their lifecycle.

PIT tagging technology has been used by fisheries scientists and managers in numerous studies including investigation of migratory behaviour at fine and large scale and enumeration of population size and related processes.

NRW has identified opportunities to apply this tagging technology as part of the index river (DSAP) monitoring programme for salmon and sea trout on the River Dee – principally to develop fishery independent and automated means of assessing returning stock size using mark-recapture methods. Other applications are envisaged within the LIFE Dee River project to evaluate the benefits, for various migratory fish species, of barrier removal and other interventions within the Dee catchment.

This project seeks to utilise automated fish counter technologies in narrow channel structures (e.g. fish passes up to ~0.5m) for the enumeration of migratory salmonids and other fish species (e.g. providing information of fish numbers, size, time and direction of passage, etc.).

For this purpose, two approaches are considered:

(i) Standalone counter deployment to evaluate passage of key fish species

(ii) Counter deployment integrated with PIT (Passive Integrated Transponder) tag detection to evaluate passage of both tagged and untagged individuals for mark-recapture purposes

NRW operates state of the art remote, non- intrusive multibeam monitoring sonars throughout Wales.

These sonars provide salmon stock assessments as well as supplying information of salmon behaviour at barriers.

In order to increase our capability and expand our fish counting network Natural Resources Wales is seeking to source additional multibeam sonars.

NRW undertakes a comprehensive programme of marine monitoring throughout Wales’ coastal waters and employs a variety of techniques to achieve this. NRW is committed to establishing a standardised approach to monitoring and to develop new methods, taking advantage of novel technology where appropriate. Side-scan sonar (SSS) combined with ground-truthing in the form of seabed photography and videography has been widely accepted as the most suitable approach for mapping many seabed habitats such as honeycomb worm reef in the subtidal zone.

In highly turbid environments, however, visibility at the seabed can be near-zero rendering optical-based ground-truthing redundant. Consequently, the true distribution and status of honeycomb worm reefs in some shallow subtidal areas around the UK remains unclear.

Acoustic Camera Imagery (ACI) collected in highly turbid waters using forward looking sonar acoustic cameras has been proven to be an effective method of ground truthing sidescan sonar in a similar manner to traditional optical video systems in clear water scenarios.

NRW operates state of the art remote, non- intrusive multibeam monitoring sonars throughout Wales.

These sonars provide salmon stock assessments as well as supplying information of salmon behaviour at barriers. Additional information: No Award