Salmon population monitoring in England and Wales (E&W): Informing stock assessment and management

Salmon population monitoring in England and Wales (E&W): Informing stock assessment and management

Salmon population monitoring in England and Wales (E&W): Informing stock assessment and management Fisheries management (including monitoring) in England and Wales (E&W) is largely the responsibility of two public bodies: (i) Environment Agency (EA) (ii) Natural Resources Wales (NRW) Prior to 1 st April 2013, both jurisdictions (England and Wales) were covered by the Environment Agency. EA and NRW still retain similar approaches to working - including common systems supporting fisheries monitoring.

Extent of the resource: 80 rivers in E&W regularly support salmon. This includes 68 principal rivers all with Salmon Action Plans and Conservation Limits (CLs) Also 17 SAC (Special Areas of Conservation) rivers with salmon as a named feature.

Extent of the resource: All support salmon rod fisheries - latest 10-year mean catch ranging from 2 (Gwyrfai/Piddle) to ~4,000 (Tyne). Some also have net fisheries - mean catch ranging from 0 (27 fisheries) to ~6,000 (NE coast drift nets).

Monitoring activities:

Monitoring activities:

Monitoring activities: Collected via a licence return from all (~80) rivers (~275 net licences; 35,000 rod licences). National E&W rod licence in place since 1992 (regional licences before then). Long-term data sets (100+ years in some cases). Include sea trout as well as salmon. Catchment scale. Provide measures of stock as well as fishery performance.

Monitoring activities: Data: Catch (killed/released) Fishing effort (licences/days/tides) CPUE Timing (day/week/month) Fishing method Weight composition Socio-economics (e.g. demographics/expenditure) Local schemes (e.g. logbooks/scale sampling)

Monitoring activities:

Monitoring activities: Include all main salmon rivers. Provide measures of fry/parr abundance and distribution. Medium term data sets (30+ years in some cases). Include trout as well as salmon. Site/sub-catchment scale.

Monitoring activities: Include all principal salmon rivers (and other smaller National systems). programme with survey design common to E&W. Provide measures of fry/parr abundance. Most sites 30-50m long and fished semiquantitatively term data sets (single (30+ run/un-netted). years in some Medium cases). Summer sampling (~July-September). Include trout as well as salmon. Survey design includes sites fished Site/subcatchment annually/biannually scale. and 6-yearly to detect temporal and spatial changes (~600 sites per year).

Monitoring activities: Data: Abundance (count/density) Length composition Age composition (fry/parr) Site features (length/width/area/habitat)

Monitoring activities:

Monitoring activities: 8 counters currently provide Returning Stock Estimates (RSEs) for salmon. Time-series: 9-27 years. 4 of the above counters also produce RSEs for sea trout. Catchment scale.

Monitoring activities: Data: Run size (daily/monthly/annual) Run timing (daily/monthly/annual) Size composition (signal strength/video) Speciation (signal strength/video) Environmental variables (e.g flow/temperature)

Monitoring activities:

Monitoring activities: Primarily confined to the Index Rivers (Tamar; Dee; Lune) plus some others (e.g. Caldew,Taff). Collect biological information from returning fish (e.g. age and size composition) Combined with RSEs on the Index Rivers (RSEs on the Dee derived from trapping/mark-recapture). Time-series: 15-25 years. Include sea trout as well as salmon. Catchment scale.

Monitoring activities: Data: Run size (River Dee only - monthly/annual) Run timing (daily/monthly/annual) Age composition (sea/river) Size composition (length/weight) Sex (external characteristics) General condition (e.g. parasites/disease) Screening for tag returns (e.g CWTags) Environmental variables (e.g flow/temperature) Other (e.g. back-calculated freshwater/marine growth)

Monitoring activities:

Monitoring activities: Mainly confined to the Index Rivers (Frome; Tamar; Dee). Primary purpose to produce mark-recapture estimates of smolt output and return rate. Time-series: 11-21 years. Include sea trout as well as salmon. Catchment scale.

Monitoring activities: Data: Run size (annual) Run timing (daily/monthly) Return rates as adults ("marine suvival") Age composition (river) Size composition (length/weight) Environmental variables (e.g flow/temperature) Other (e.g. back-calculated freshwater growth)

Monitoring activities: All ~80 salmon rivers

Monitoring activities: All ~80 salmon rivers All ~80 salmon rivers

Monitoring activities: All ~80 salmon rivers Tyne Kent All ~80 salmon rivers Lune Dee 8 counted rivers producing salmon RSEs Fowey Tamar Frome Test and Itchen Hants Avon

Monitoring activities: All ~80 salmon rivers Tyne All ~80 salmon rivers 8 counted rivers producing salmon RSEs Lune Dee 4 adult trapping/tagging programmes associated with Index Rivers Tamar

Monitoring activities: All ~80 salmon rivers All ~80 salmon rivers Dee 8 counted rivers producing salmon RSEs 4 adult trapping/tagging programmes associated with Index Rivers 3 smolt trapping/tagging programmes associated with Index Rivers Tamar Frome

Application of monitoring data: Assessment procedures: Data from all sources are integrated and applied in wide variety of ways in stock and fishery assessments. This includes the use of generic stock assessment models applied nationally to adults (e.g. Conservation Limit compliance procedures) and juveniles (e.g. WFD fish classification of Water Body ecological status ). Additional information on stock biology and environmental factors is used alongside these standard assessment methods in reviewing stock status.

Application of monitoring data: Applications include: Annual assessment and reporting of salmon stock status and fishery performance to meet national (E&W) and international (ICES /NASCO) obligations. River Basin Management Planning (6-yearly cycle) to identify and address environmental issues on failing Water Bodies. Implementation and review of fisheries regulations and controls (e.g. Net Limitation Orders and byelaws). Tracking of long-term changes in stock abundance and composition to improve understanding of factors influencing change and to better inform fisheries and environmental management.

Example: Development and use of Conservation Limits Data: Procedure: Purpose/Application: Rod catch statistics Catch (number, weight composition, C&R) Fishing effort Spawning escapement/egg deposition estimates Conservation Limit development and compliance assessment Fry/parr abundance estimates Habitat variables Carrying capacity modelling 'Returning Stock Estimates' Exploitation rate modelling Biological characteristics Age-weight keys (e.g. age; size; sex) Other biological data Smolt output and return ('marine survival') Stock-recruitment modelling

Smolts Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Derived stock-recruitment curve for the River Severn Example: Development and use of 180,000 160,000 Conservation 140,000 Limits 120,000 100,000 80,000 Data: Procedure: 60,000 Purpose/Application: 40,000 Rod catch statistics Catch (number, weight composition, C&R) Fishing effort 20,000 Spawning 0 escapement/egg 0.00 10.00 20.00 30.00 40.00 deposition estimates Eggs (millions) Conservation Limit development and compliance assessment Fry/parr abundance estimates Carrying capacity modelling Habitat variables 'Returning Stock Estimates' Exploitation rate modelling Biological characteristics Age-weight keys (e.g. age; size; sex) Other biological data Smolt output and return ('marine survival') Stock-recruitment modelling

Smolts Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Derived stock-recruitment curve for the River Severn Example: Development and use of 180,000 160,000 Conservation 140,000 Limits 120,000 100,000 80,000 Data: Procedure: 60,000 Purpose/Application: 40,000 Rod catch statistics Catch (number, weight composition, C&R) Fishing effort 20,000 Spawning 0 escapement/egg 0.00 10.00 20.00 30.00 40.00 deposition estimates Eggs (millions) Conservation Limit development and compliance assessment Fry/parr abundance estimates Carrying capacity modelling Habitat variables 'Returning Stock Estimates' Exploitation rate modelling Biological characteristics Age-weight keys (e.g. age; size; sex) Other biological data Smolt output and return ('marine survival') Stock-recruitment modelling

Smolts Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Derived stock-recruitment curve for the River Severn Example: Development and use of 180,000 160,000 Conservation 140,000 Limits 120,000 100,000 80,000 Data: Procedure: 60,000 Purpose/Application: 40,000 Rod catch statistics Catch (number, weight composition, C&R) Fishing effort 20,000 Spawning 0 escapement/egg 0.00 10.00 20.00 30.00 40.00 deposition estimates Eggs (millions) Conservation Limit development and compliance assessment Fry/parr abundance estimates Carrying capacity modelling Habitat variables 'Returning Stock Estimates' Exploitation rate modelling Biological characteristics Age-weight keys (e.g. age; size; sex) Other biological data Smolt output and return ('marine survival') Stock-recruitment modelling

Example: Development and use of Conservation Limits Data: Procedure: Purpose/Application: Rod catch statistics Catch (number, weight composition, C&R) Fishing effort Spawning escapement/egg deposition estimates Conservation Limit development and compliance assessment Fry/parr abundance estimates Habitat variables Carrying capacity modelling 'Returning Stock Estimates' Exploitation rate modelling Biological characteristics Age-weight keys (e.g. age; size; sex) Other biological data Smolt output and return ('marine survival') Stock-recruitment modelling

Example: Development and use of Conservation Limits Data: Procedure: Purpose/Application: Rod catch statistics Catch (number, weight composition, C&R) Fishing effort Spawning escapement/egg deposition estimates Conservation Limit development and compliance assessment Fry/parr abundance estimates Habitat variables 'Returning Stock Estimates' Carrying capacity modelling Exploitation rate modelling Biological characteristics Age-weight keys (e.g. age; size; sex) Other biological data Smolt output and return ('marine survival') Stock-recruitment modelling Log10 Extant angling exploitation rate (%) 2.00 1.50 1.00 0.50 0.00 Salmon rod exploitation rates: All rivers ex Test and Itchen R2 = 04992 P= <0.0001 Frome Tamar Fowey Dee Lune Kent Tyne Hants Avon Leven Tamar Sea trout Fowey Sea trout Dee Sea trout Kent Sea trout 0 20 40 60 80 100 120 140 Angling effort per km fishery

Proportion of grilseby month Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Example: Development and use of Conservation Limits Data: Procedure: Purpose/Application: Rod catch statistics Catch (number, weight composition, C&R) Fishing effort 1.000 Spawning 0.500 escapement/egg 0.000 deposition estimates 1.000 June Conservation Limit development and compliance assessment 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 July 0.500 Fry/parr abundance estimates Carrying capacity modelling 0.000 1.000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 August Habitat variables 0.500 0.000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1.000 September 'Returning Stock Estimates' Exploitation rate modelling 0.500 0.000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1.000 October 0.500 0.000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Biological characteristics Age-weight keys (e.g. age; size; sex) Other biological data 1.000 0.500 0.000 November 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1.000 Decemeber Smolt output and return ('marine survival') Stock-recruitment modelling 0.500 0.000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Weight (Lbs)

Smolts Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Example: Development and use of Conservation Limits Data: Procedure: Purpose/Application: Rod catch statistics Catch (number, weight composition, C&R) Fishing effort 250,000 Spawning escapement/egg deposition estimates Conservation Limit development and compliance assessment River Dee: Egg-to-smolt Ricker S-R relationship Fry/parr abundance estimates Carrying capacity modelling 200,000 Habitat variables 150,000 'Returning Stock Estimates' Exploitation rate modelling 100,000 50,000 Biological characteristics Age-weight keys (e.g. age; size; sex) Other biological data 0 0 5 10 15 20 25 30 Eggs (millions) Smolt output and return ('marine survival') Stock-recruitment modelling

Run estimate Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Example: Long-term changes in stock abundance and composition 12,000 10,000 Salmon run estimate; River Dee 1992-2014 All sea ages 8,000 6,000 4,000 2,000 0 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Return year 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

% Return to homewaters Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Example: Long-term changes in stock abundance and composition 10.0 Salmon smolt return rates ; River Dee, 1993-2012 8.0 6.0 4.0 2.0 0.0 1990 1995 2000 2005 2010 2015 Smolt year

Sea age composition Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Example: Long-term changes in stock abundance and composition 100% Salmon sea age composition; River Dee, 1966-2014 80% 60% 40% 20% 0% 2014 2012 2010 2008 2006 2004 2002 2000 1998 1996 1994 1992 1990 1988 1986 1984 1982 1980 1978 1976 1974 1972 1970 1968 1966 1964 1962 1960 Return year Previous spawners 4SW fish 3SW fish 2SW fish 1SW fish

Mean smolt age Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Example: Long-term changes in stock abundance and composition 2.20 Mean smolt age; River Dee salmon, 1964-2013 2.00 1.80 1.60 1.40 1.20 1SW fish 2SW fish 1.00 1960 1970 1980 1990 2000 2010 2020 Smolt year

Mean Condition Factor Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Example: Long-term changes in stock abundance and composition Variation in Fulton's Condition Factor: River Dee salmon, all months, 1991-2014 1.160 1.140 1.120 1.100 1SW fish 2SW fish 1.080 1.060 1.040 1.020 1.000 0.980 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 Adult return year

Mean Condition Factor % Return to homewaters Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Example: Long-term changes in stock abundance and composition 12.0 10.0 8.0 6.0 4.0 2.0 R2 = 0.627 P =<0.001 1.160 1.140 0.0 1.120 1.040 1.050 1.060 1.070 1.080 1.090 1.100 1.100 Fulton's condition factor 1.080 Variation in Fulton's Condition Factor: River Dee salmon, all months, 1991-2014 1SW fish 2SW fish 1.060 1.040 1.020 1.000 0.980 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 Adult return year

Mean weight (g) Salmon population monitoring in E&W: Morfish conference, 3 rd March 2015 Example: Long-term changes in stock abundance and composition Variation in weight: River Dee Salmon, all months, 1991-2014 8000 7000 1SW fish 2SW fish 6000 5000 4000 3000 2000 1000 0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Adult return year