River Plym SAP Consultation Item Type monograph Publisher Environment Agency Download date 02/10/2021 13:54:08 Link to Item http://hdl.handle.net/1834/27365 River Plym Salmon Action Plan – Consultation Document Table of Contents Table of Contents ....................................................................................................................... 1 List of Figures ............................................................................................................................ 2 List of Tables ............................................................................................................................. 2 EXECUTIVE SUMMARY ..................................................................................................... 4 PART 1. INTRODUCTION .................................................................................................... 6 PART 2. DESCRIPTION OF THE CATCHMENT ............................................................ 7 PART 3. DESCRIPTION OF THE FISHERY ................................................................... 14 3.1 SUMMARY OF THE RIVER PLYM FISHERY ......................................................... 14 3.1.1 The River Plym rod fishery..................................................................................... 14 3.1.2 Additional Legislation of Relevance to the Salmonid Fishery. .............................. 15 3.2 CATCHES AND CATCH EFFORT ............................................................................. 17 3.2.1 Salmon Rod Catches ............................................................................................... 17 3.2.2 Sea Trout Rod Catches............................................................................................ 22 3.3 PARTICIPATION AND FISHERY VALUE ............................................................... 23 3.3.1 Participation ............................................................................................................ 23 3.3.2 Economic Evaluation of the Salmon Fishery.......................................................... 24 3.3.3 Other Aspects of Economic Value .......................................................................... 25 3.3.4 Impact of the rod fishery on the economy .............................................................. 26 PART 4. DESCRIPTION OF STOCKS, CURRENT STATUS AND TRENDS ............ 26 4.1 STOCK MONITORING ................................................................................................ 26 4.1.1 Adults ...................................................................................................................... 27 4.1.2 Juveniles .................................................................................................................. 28 4.2 JUVENILE ABUNDANCE........................................................................................... 28 4.2.1 Salmon Fry Abundance........................................................................................... 29 4.2.2 Salmon Parr Abundance ......................................................................................... 30 4.2.3 Trout Fry and Trout Parr Abundance...................................................................... 31 4.2.4 Other Fish Species .................................................................................................. 32 4.3 DISTRIBUTION OF SPAWNING AND UTILISATION OF THE CATCHMENT ... 37 PART 5. ASSESSMENT OF STOCK AND FISHERY PERFORMANCE ..................... 39 5.1 CONSERVATION LIMITS .......................................................................................... 39 5.1.1 Historic Egg Deposition and Compliance Assessment ........................................... 41 5.2 FRESHWATER PRODUCTION .................................................................................. 42 5.3 DIVERSITY and FITNESS ........................................................................................... 43 PART 6. LIMITING FACTORS. ......................................................................................... 44 6.1 Fishery limiting factors for the River Plym ................................................................... 45 6.2 Biological limiting factors for the River Plym .............................................................. 45 6.3 Environmental limiting factors for the River Plym ....................................................... 45 6.4 Key Issues on the Plym Catchment ............................................................................... 46 PART 7. ISSUES AND ACTIONS ....................................................................................... 55 Factors Affecting Habitat and Limiting Salmon Stocks .................................................. 55 Monitoring of adult upstream migration .......................................................................... 56 Diminishing run size of salmon ....................................................................................... 56 Illegal fishing ................................................................................................................... 57 Exploitation of mixed salmon stocks in distant water fisheries ....................................... 57 Restrictions to upstream salmon migration...................................................................... 57 Potential mortalities due to in river abstractions.............................................................. 57 1 River Plym Salmon Action Plan – Consultation Document PART 8. FUNDING THE PLAN .......................................................................................... 58 8.1 THE FUNDING BACKGROUND................................................................................ 58 8.2 CURRENT ACTIONS .................................................................................................. 58 8.3 COLLABORATIVE FUNDING ................................................................................... 59 PART 9. THE CONSULTATION PROCESS .................................................................... 60 PART 10. APPENDICES ...................................................................................................... 61 APPENDIX (1) Setting Conservation Limits (CL) and Assessing compliance. ................. 61 APPENDIX (2) Limiting factors in the marine phase of the salmon life cycle .................. 64 PART 11. GLOSSARY .......................................................................................................... 67 PART 12. REFERENCES. .................................................................................................... 70 List of Figures Figure 1 - Map of River Plym catchment ................................................................................ 11 Figure 2 - Map of the River Plym and areas delimited by Estuarine and Coastal Fisheries Byelaws .................................................................................................... 16 Figure 3 - Declared rod catch of Salmon for the River Plym – 1959 to 2002 ......................... 17 Figure 4 - River Plym monthly total rod catch of Salmon - 1964 to 2002 .............................. 19 Figure 5 - Relative proportions of pre- and post- 1st June Salmon within the total declared rod catch - 1964 to 2002 ......................................................................................... 20 Figure 6 - November and December declared rod catches of Salmon as a percentage of the total post- 1st June rod catch - 1972 to 2002 ..................................................... 21 Figure 7 - Catch per Licence Day for rod caught Salmon on the River Plym ......................... 22 Figure 8 - Declared rod catch of Sea Trout for the River Plym - 1959 to 2002 ...................... 23 Figure 9 - 2002 FCS grades Salmon 0+ ................................................................................. 33 Figure 10 - 2002 FCS grades Salmon >=1+ ............................................................................ 34 Figure 11 - 2002 FCS grades Trout 0+ .................................................................................... 35 Figure 12 - 2002 FCS grades Trout >=1+................................................................................ 36 Figure 13 - 1995 River Meavy redd count data ....................................................................... 37 Figure 14 - 1999 River Meavy redd count data ....................................................................... 37 Figure 15 - Diagrammatic Stock Recruitment curve ............................................................... 39 Figure 16 - River Plym historic egg deposition compliance.................................................... 41 Figure 17 - Limiting factors impacting upon the salmon life cycle ......................................... 44 List of Tables Table 1 - RQO Summary – Review of Water Quality Compliance data for 2001 .................... 8 Table 2 - Licensed Abstractions within the River Plym Catchment ........................................ 12 Table 3 - Number of River Plym salmonid deaths reported due to UDN ................................ 21 Table 4 - Declared Salmon rod catch summary. ...................................................................... 22 Table 5 - Rod Fishery participation ......................................................................................... 23 Table 6 - Value of the River Plym Fishery to Fishery Owners (Market value)