Results & Discussion

3. Results

WRT surveyed 41 semi-quantitative sites on the River Teign in August and September, a repeat of the 2021 program. In addition to four sites on the South Teign (for South West Water), a further five semi-quantitative surveys were funded by donations towards the River Teign electric fishing programme by the Woodland Trust. Survey conditions were challenging, with high air and water temperatures, and a degree of habitat fragmentation was recorded. It should be noted that summer 2022 was the driest since 1995 as well as the second hottest year on record. As with previous years, surveyors kept a close eye on river water temperatures to ensure surveying did not proceed if water temperatures exceeded 18°C, in accordance with Environment Agency guidance.

As in previous years, the 2022 catchment survey demonstrates that the Teign catchment supports excellent salmonid spawning and the importance of large, main river stem spawning sites for salmon reproduction. There were 13 excellent classification sites in 2022 for salmon fry, along with six good sites. Salmon fry were absent from 17 of the 49 sites (35%), with some of these sites being historically absent of salmon, mainly due to obstructions and poor habitat Trout numbers remain quite robust, there were 12 excellent classification sites for trout fry as well as ten good classification sites in 2022, with trout fry absent from nine of the 49 sites (18%). A total of 1184 salmon (fry and parr) and 767 trout (fry and parr) were caught across all 49 sites in the Teign catchment. The best performing sites for juvenile salmonids were; Sowton Mill on the main River Teign (203 salmon fry) and the Liverton Brook for trout fry (53) Although most of the salmon spawning occurs on the main river, some tributaries, such as the Blackaton Brook also produced strong scores (Table 2). Considering the prevailing conditions over summer, this slight increase in total catch is considered a positive outcome.

South Teign results are discussed as part of a separate report, as the surveys are associated with monitoring of the gravel augmentation and habitat improvements associated with the South West Water asset, Fernworthy Reservoir. However, notably salmon fry were recorded again at Yardworthy/Wonacott, this represents the farthest penetration of salmon through the River Teign catchment, approximately 45km from the tidal estuary.

Usually where salmon fry are absent from a riffle site, trout fry predominated Conversely, where large numbers of juvenile salmon are found, the brown trout are often outcompeted and ‘pushed out’ into other habitats such as smaller tributaries. Therefore, any sites where large numbers of salmon are recorded alongside low trout numbers should not be taken as a lack of trout, it is highly likely that the brown trout are not truly absent, but that the surveys did not locate them. Examples of such sites would be ‘Mill End’ , ‘Rushford Mill’ and ‘D/S Fingle Bridge’ in Table 2.

Figure 5 Total catch for salmon and trout fry, River Teign 2022

Figure 6 Salmon fry classifications, River Teign 2022

Figure 7 Trout fry classifications, River Teign 2022

The graph below helps to illustrate the long-term trends and variability of salmon and trout fry numbers in the Teign catchment. Individual trends in salmon and trout can be visualised, along with the combined average fry numbers for the river. Salmon data is shown to be more variable year to year, whereas trout data tends to be more stable, with

a general upward trend. This assessment suggests that average salmon and trout fry catch has increased since 2021 with more salmon than trout overall, as expected possibly due to a focus on salmon habitat sites. The average fry numbers were highest in 2013, followed by the lowest in 2014. However, number and location of sites do change year on year so although an average can be produced and aid in visualising salmonid density in the catchment there are several influential variables to consider.

In general, 2022 shows an improvement on the 2021 data for both salmon juveniles (Figure 8), brown trout juveniles (Figure 9) and the overall juvenile salmonid population (Figure 10) across the Teign catchment and its tributaries. Some exceptional sites were recorded on the main river for Atlantic salmon, with ‘Rushford Mill’ (128 fry), ‘D/S Clifford Bridge’ (116 fry), ‘D/S Clifford Bridge (149 fry) and ‘Sowton Weir’ (203 fry) (refer to Table 2). It has been considered that these high numbers may have been a result of condensed habitat due to low water. However, the author would submit that this is not the case, as the limiting factor in semi-quantitative surveying is time (5 minutes of fishing) and so the same fishing effort is delivered regardless of wetted area.

The results also elegantly illustrate the interspecific competition that occurs when high numbers of juvenile Atlantic salmon are present. For example, in the same exceptional sites above, trout were absent from all cited surveys apart from ‘Rushford Mill, where one brown trout was found (refer to Table 2). Furthermore, where Atlantic salmon juveniles were not present, strong numbers of brown trout were recorded. Examples from smaller tributaries and the main stem of the Teign include the ‘Rookery Brook’ (0 Atlantic salmon

– 42 brown trout), ‘Liverton Brook’ (0 - 53), ‘Beetor Bridge’ on the River Bovey (0 – 43) and at ‘Halls Cleave’ on the main River Teign (0 – 35) (refer to Table 2).

Overall, 2022 in comparison to previous years has shown positive results for the spawning production of both brown trout and Atlantic salmon.

4. Recommendations

The WRT EF surveys are undertaken to gain an understanding on annual recruitment of salmon and trout, but they have slightly different habitat preferences, and one species will often dominate over the other where the other has limited or no presence. There will be natural annual variations in populations, and this is to be expected depending on the success of the adult return numbers, winter river conditions and habitat limitations that may arise. Despite trout fry populations increasing in some areas, it is equally important that defence strategies are put in place to maintain good recruitment and to restore numbers elsewhere in the Teign. In areas where salmon have decreased, the repair strategy and appropriate actions should be implemented where funding allows. Therefore, management strategies need to be considered for each species, hence a conservation strategy for both salmon and trout.

The strategy for restoration and conservation of sites suggested here broadly follows the “Defend, Repair, Attack” (DRA) concept (Table 5) developed by Ronald Campbell of the Tweed Foundation, and has, in the past, been applied locally in the Exe catchment by the River Exe and Tributaries Association project. The fry productivity of the rivers is assessed by a combination of historic semi-quantitative electric fishing results. These results are then applied in context of existing plans (e.g. Salmon Action Plan, habitat walkover surveys and genetic data) to produce assessments and recommendations for each subcatchment of the river. These sub-catchments are classified according to three levels: Defend, Repair, and Attack.

Despite the DRA strategy being a useful tool to identify and prioritise works in catchments, the requirements of waterbodies can rarely be quite so clear cut. The coloured arrow in Table 5 represents the continuum of the three strategies and the goal for each waterbody; to move all the Teign sites from their current position to somewhere in the Defend category, or to ensure they remain in this status if fish stocks are already good.

Recommended works:

Gravel augmentation: Continue to conduct gravel augmentation on the South Teign and monitor gravel deposition through gravel audit surveys to determine requirement for future gravel augmentations.

Fencing: Riparian zones identified as receiving significant livestock access, with apparent habitat degradation, should be fenced to limit trampling and bank side poaching Precautions should be taken to ensure livestock can access drinking water supply. Effective buffer strips dependant on site characteristics is advised.

Coppicing: Targeted selective coppicing of woodland and abandoned riparian coppice adjacent to juvenile habitat riffles should be undertaken This will increase primary productivity and food source for juvenile fish. Shade should be maintained on deeper pools and runs for water temperature and adult fish habitat cover.

Erosion Control: Fencing and effective marginal habitat management will reduce erosion. However, where specific areas of high pressure and vulnerability are identified, erosion

protection measures such as woody debris installation, environmentally sensitive revetments, and strategic tree planting would be advantageous.

Fish Passage Assessment: Assessment of potential fish migration barriers using the Coarse Resolution Rapid Assessment technique developed by the Scottish and Northern Irish Forum For Environmental Research (SNIFFER). A standardised survey technique to assess impact of in-channel structures.

In-Channel Habitat Restoration: Installation and construction of habitat enhancing features, including woody debris introduction, flow manipulation with groins and kickers, bank reprofiling for marginal zonation, strategic tree planting, gravel introduction and riffle creation, and historic channel restoration. Advanced management usually applied post success of other recommended actions.

Modify flow regime: Where flows are impacted by storage reservoirs, liaise with service provider to discuss and inform of findings of EF surveys to determine management of flow regime from impoundments at appropriate times of years for fisheries benefit.

Walkover Surveys: Recording of habitat availability relating to ontogenetic stages of fish, including observed local land use and factors negatively impacting habitat quality. Often the starting point for work in an area following from poor fry index survey results. An important component of catchment management. Walkovers essentially build wide scale understanding of a catchment and allow forging of relationships with local landowners.

Interpretation: Sensitive spawning sites can be exposed to disturbance at key times of year. Interpretation boards can be used to inform of salmonid presence and advise on in river site avoidance.

Assess monitoring effort: By adapting survey effort, appropriate information can be gained according to strategic plans for the catchment based on current and historic data. It is recommended that redd observations be encouraged annually to coincide with fry index survey data. Continue with volunteer invertebrate monitoring e.g. Riverfly, and WRT recommended the Citizen Science Investigation (CSI) programmes run by WRT.

These works should be tailored to each sub catchment and prioritised according to the status of the river bodies. Table 7 displays the recommended works required in each waterbody to restore habitat and increase fry populations.

Gravel augmentation on the South Teign continued in 2022 with 96 tonnes of granite gravel introduced into the South Teign at two sites, below the dam wall and at Yardworthy Farm. Fisheries bank releases is currently under investigation on the South Teign and Fernworthy Dam SWW have recently begun a compensation flow release from the Kennick, Tottiford and Trenchford reservoirs. SWW is undertaking adaptive management trials on the Beadon Brook to improve the habitat for salmonids under an AMP7 (20202025) Water Industry National Environment Programme (WINEP) scheme to meet the Heavily Modified Water Body (HMWB) requirements to mitigate the impact of Kennick, Tottiford and Trenchford (KTT) reservoirs on the Beadon Brook. The first gravel

augmentation activities were carried out by WRT in 2022, with approximately 30 tonnes of granite gravel transferred to the brook. Monitoring is being carried out to determine success of this and scalability of the gravel augmentation for future years.

5. Acknowledgements

Thanks to all landowners involved for their kind permission and to the Environment Agency for providing consent for the surveys.

We would also like to thank the Teign Angling and Conservation Association, South West Water and the Woodland Trust for providing funding, donation and support for the 2022 surveys. Particular thanks go to TACA volunteer Neil Yeandle and River Teign Restoration Project Officers Geoff Stephens and Louise Davis for their efforts in making up the electric fishing team and to Roger Furniss for his involvement and efforts in planning these surveys.