# Benchmarking the north atlantic salmon stock assessment: a new life cycle model to evaluate salmon mixed stock status and fisheries management scenarios across the north atlantic basin

Maxime Olmos, Remi Lemaire-Patin, Pierre-yves Hernvann, James Ounsley, Maud Queroue, Geir Bolstad, Peder Fiske, Gérald Chaput, Etienne Prévost, Marie Nevoux, et al.

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## To cite this version:

Maxime Olmos, Remi Lemaire-Patin, Pierre-yves Hernvann, James Ounsley, Maud Queroue, et al. Benchmarking the north atlantic salmon stock assessment: a new life cycle model to evaluate salmon mixed stock status and fisheries management scenarios across the north atlantic basin. ICES Scientific Reports, 2023, ICES Scientific Reports, 5 (112), 85 p. 10.17895/ices.pub.24752079. http://hal-04337713v2

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# Benchmarking the north atlantic salmon stock assessment: a new life cycle model to evaluate salmon mixed stock status and fisheries management scenarios across the north atlantic basin

Maxime Olmos, Remi Lemaire-Patin, Pierre-Yves Hernvann, James Ounsley, Maud Queroue, Geir Bolstad, Peder Fiske, Gérald Chaput, Etienne Prévost, Marie Nevoux, et al.

► To cite this version:

Maxime Olmos, Remi Lemaire-Patin, Pierre-Yves Hernvann, James Ounsley, Maud Queroue, et al. Benchmarking the north atlantic salmon stock assessment: a new life cycle model to evaluate salmon mixed stock status and fisheries management scenarios across the north atlantic basin. 2023. hal-04337713v4

HAL Id: hal-04337713

https://hal.inrae.fr/hal-04337713v4

Preprint submitted on 30 Oct 2025

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**Author(s):** Perälä, Tommi; White, Jonathan; Adams, Grant; April, Julien; Bárðarson, Hlynur; Ahlbeck Bergendahl, Ida; Bolstad, Geir; Breau, Cindy; Bull, Colin; Chaput, Gerald; Cooper, Anne; Dauphin, Guillaume; Erkinaro, Jaakko; Gillson, Jonathan; Gregory, Stephen; Jepsen, Niels; Kermoade, MacKenzie; Lebot, Clément; Legault, Chris; Maxwell, Hugo; McGinnity, Philip; Meerburg, David; Millane, Michael; Nadolna-

**Title:** Benchmark Workshop on Atlantic Salmon (Salmo salar) in the North Atlantic (WKBSALMON)

**Year:** 2023

**Version:** Published version

**Copyright:** © 2023 International Council for the Exploration of the Sea

**Rights:** CC BY 4.0

**Rights url:** https://creativecommons.org/licenses/by/4.0/

**Please cite the original version:**

Perälä, T., White, J., Adams, G., April, J., Bárðarson, H., Ahlbeck Bergendahl, I., Bolstad, G., Breau, C., Bull, C., Chaput, G., Cooper, A., Dauphin, G., Erkinaro, J., Gillson, J., Gregory, S., Jepsen, N., Kermoade, M., Lebot, C., Legault, C., ... Wennevik, V. (2023). Benchmark Workshop on Atlantic Salmon (Salmo salar) in the North Atlantic (WKBSALMON). International Council for the Exploration of the Sea. ICES Scientific Reports, 5:112.

https://doi.org/10.17895/ices.pub.24752079
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# Review of the Atlantic Salmon NAC Pre-Fishery Abundance (PFA) and Catch Advice Model for West Greenland

Gérald Chaput, Etienne Prévost

► To cite this version:

Gérald Chaput, Etienne Prévost. Review of the Atlantic Salmon NAC Pre-Fishery Abundance (PFA) and Catch Advice Model for West Greenland. 2023. hal-04337622

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# BENCHMARK WORKSHOP ON ATLANTIC SALMON IN THE NORTH ATLANTIC (WKBSALMON)

## VOLUME 5 | ISSUE 112

ICES SCIENTIFIC REPORTS

RAPPORTS
SCIENTIFIQUES DU CIEM

<figure><img src="image_3.png" /></figure>

ICES INTERNATIONAL COUNCIL FOR THE EXPLORATION OF THE SEA
CIEM COUNSEIL INTERNATIONAL POUR L'EXPLORATION DE LA MER
# Review of the Atlantic Salmon NAC Pre-Fishery Abundance (PFA) and Catch Advice Model for West Greenland

G. Chaput and É. Prévost¹

Fisheries and Oceans Canada, Moncton, Canada

¹ Institut national de recherche pour l'agriculture, l'alimentation et l'environnement, France

## TABLE OF CONTENTS

<table><tr><td>INTRODUCTION</td><td>2</td></tr><tr><td>PROGRESSION OF NAC PFA AND FORECAST MODELS USED AT ICES</td><td>3</td></tr><tr><td>NAC PFA MODEL</td><td>5</td></tr><tr><td>NAC REGION DISAGGREGATED PFA MODEL</td><td>6</td></tr><tr><td>Materials and Methods</td><td>7</td></tr><tr><td>Modelling the lagged spawners to 2SW returns</td><td>7</td></tr><tr><td>PFA to returns of 2SW fish to regions of North America</td><td>8</td></tr><tr><td>Regional apportioning of the 2SW catches in Newfoundland, Labrador and St. Pierre and Miquelon fisheries</td><td>10</td></tr><tr><td>FORECASTS AND CATCH OPTION SCENARIOS (ICES 2021)</td><td>10</td></tr><tr><td>RETROSPECTIVE ANALYSIS OF MODEL</td><td>11</td></tr><tr><td>RESULTS AND DISCUSSION</td><td>11</td></tr><tr><td>PFA TO LS PRODUCTIVITY</td><td>11</td></tr><tr><td>PFA ESTIMATES</td><td>11</td></tr><tr><td>Forecasts of productivity and PFA for PFA years 2021 to 2023</td><td>12</td></tr><tr><td>RETROSPECTIVE ANALYSIS OF MODEL</td><td>12</td></tr><tr><td>REFERENCES</td><td>13</td></tr><tr><td>TABLES</td><td>16</td></tr><tr><td>FIGURES</td><td>23</td></tr></table>
International Council for the Exploration of the Sea
Conseil International pour l'Exploration de la Mer

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Denmark

Telephone (+45) 33 38 67 00

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www.ices.dk

info@ices.dk

ISSN number: 2618-1371

This document has been produced under the auspices of an ICES Expert Group or Committee. The
contents therein do not necessarily represent the view of the Council.

© 2023 International Council for the Exploration of the Sea

This work is licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0). For
citation of datasets or conditions for use of data to be included in other databases, please refer to ICES
data policy.

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# INTRODUCTION

Atlantic salmon (*Salmo salar* L.) from anadromous populations of eastern North America can undertake extensive feeding migrations generally throughout the North Atlantic. Salmon from many different stock areas can aggregate at certain periods near Greenland and in the Norwegian Sea and these feeding aggregations attracted the attention of fishermen and resulted in fisheries on mixed-stocks during the first and second years at sea. Sampling of the fishery catches, analyses of biological characteristics, and recaptures of salmon originally tagged in homewaters indicated that the salmon in these fisheries originated from a large number of salmon producing areas in the North Atlantic, from both eastern North America and the northeast Atlantic areas (Saunders et al. 1965; Paloheimo and Elson 1974; Reddin et al. 2012). Recent genetic stock identification analyses of salmon of North American origin captured at West Greenland indicate the diverse regional contribution of salmon to these fisheries, including major (> 20%) contributions from three regional groups (Labrador, Quebec, Gulf) in eastern North America and minor (< 5% per) contributions from the three other regions (Bradbury et al. 2016b; Figure 1). The harvests were also predominantly of salmon in their second year at sea that had not previously spawned, and therefore represented recruitment to the spawning stock with the expectation that many of those that survived would have returned to homewaters as two-sea-winter salmon (ICES 2016).

There was sufficient concern regarding the impact of the Greenland mixed stock fishery on salmon populations in homewaters of both eastern North America (Paloheimo and Elson 1974) and in the northeast Atlantic that a regional fisheries management organisation (RFMO), called the North Atlantic Salmon Conservation Organization (NASCO), was formed by international convention in 1983 for the purpose of negotiating fishery agreements for the high seas Atlantic salmon fisheries. Signatories to the NASCO convention included parties from all salmon producing countries in the North Atlantic as well as parties (Denmark on behalf of Greenland and the Faroe Islands) that fished salmon in the high seas. Being strictly an RFMO, NASCO did not have the scientific structure to assess the status of salmon populations in the North Atlantic and consequently solicited scientific advice from an independent science body, the International Council for the Exploration of the Sea (ICES). ICES was formed in 1902, received full international status by international convention in 1964, and is an independent scientific body supported financially and professionally by countries in the North Atlantic, including North America. ICES, in its scientific mandate, was involved from the beginnings of NASCO in 1984, initially in the development of fishery monitoring programs and in the assessment of fishing practices at Greenland (ICES 1984).

The ICES Expert Group that addressed the questions from NASCO is called the Working Group on North Atlantic Salmon (WGNAS). This working group has convened annually since 1984, and twice annually in the earlier years. The reports prepared by ICES WGNAS contain a large amount of historical information on the characteristics of homewater and mixed stock fisheries and catches, on population specific indices of abundance including returns and spawning escapements, on indices of return rates of smolts and depending on the year, information on specific topics of interest related to emerging threats or innovations to Atlantic salmon conservation and management. The WGNAS reports have grown in volume over time as the questions from NASCO increased but also because the WGNAS reports are unique compilations of the historical and contemporary information on fisheries, status and trends of Atlantic salmon in the North Atlantic. Some of the information used by ICES to develop summaries of stock status (Chaput 2012), that describe the origin of salmon in mixed stock fisheries (Reddin and Friedland 1999; Reddin et al. 2012; Bradbury et al. 2016b), that describe approaches used to develop region and continent wide indices of abundance (Potter et al. 2004) and that document specific models for the provision of catch advice (Chaput et al. 2005) have been published in the primary literature.

The statistical treatment of data and the development of models have advanced from the initial approaches documented in ICES (1994). The changes in statistical modelling approaches represent a paradigm shift in the consideration of data inputs and the previous treatment of derived values as
# BENCHMARK WORKSHOP ON ATLANTIC SALMON IN THE NORTH ATLANTIC (WKBSALMON)

## Recommended format for purpose of citation:

ICES. 2023. Benchmark Workshop on Atlantic salmon in the North Atlantic (WKBSALMON). ICES Scientific Reports. 5:112. 85 pp. https://doi.org/10.17895/ices.pub.24752079

## Editors

Tommi Perälä • Jonathan White

## Authors

Grant Adams • Julien April • Hlynur Bárðarson • Ida Ahlbeck Bergendahl • Geir Bolstad • Cindy Breau • Colin Bull • Gerald Chaput • Anne Cooper • Guillaume Dauphin • Jaakko Erkinaro • Jonathan Gillson • Stephen Gregory • Niels Jepsen • MacKenzie Kermoade • Clément Lebot • Chris Legault • Hugo Maxwell • Philip McGinnity • David Meerburg • Michael Millane • Katarzyna Nadolna-Ałtyn • Maxime Olmos • James Ounsley • Rémi Patin • Stig Pedersen • Tommi Perälä • Etienne Rivot • Martha Robertson • Tim Sheehan • Tom Staveley • Andrew Taylor • Alan Walker • Vidar Wennevik • Jonathan White
equivalent to observations. In particular, the estimation of abundance by sea age group, modelling and catch advice components of the mixed stock fishery question have changed from disjoint and independent analysis components to a coherent inference and forecast approach that integrates all aspects of this dynamic into a sequential and related process from spawners, through survival, harvests in fisheries to returns to homewaters (Olmos et al. 2019; ICES 2021a). The most recent catch advice for the West Greenland fishery from ICES was provided for the fishing years 2021 to 2023 using the PFA forecast model that considered only the 2SW returns and 2SW spawners to six regions of NAC (ICES 2021b). The proposed version going forward, and which is reviewed in the ICES Benchmark process, is the life-cycle model (LCM) approach described by Massiot-Granier et al. (2014), Olmos et al. (2019), and ICES (2021a); the LCM has yet to be implemented by ICES for inference, forecasting and catch advice.

## PROGRESSION OF NAC PFA AND FORECAST MODELS USED AT ICES

For a number of years, ICES (e.g. 1994, 2015) provided catch advice for the West Greenland fishery using various models at the North American stock complex level to forecast PFA for the upcoming fishery year at Greenland based on the run-reconstruction approach and one or two continent-wide explanatory variables (Table 1).

A stock independent explanatory variable for PFA was proposed based on an association between catch rates of salmon at sea and sea surface temperature (SST). Using a demonstrated curvilinear relationship between catch rates (number of salmon captured per length of net and soak time) of salmon and SST, the habitat area favourable to salmon production was calculated based on SST values in an area north of 41ºN latitude and west of 21ºW longitude, an area encompassing 5.36 million km², that was considered to include most of the known locations at sea for salmon of North American origin. The relative index of the area suitable for salmon was developed by weighting the area within 2 deg squares at each temperature group by the catch rate for the same temperature group. Correlations between PFA values derived from run-reconstruction and time periods for the habitat index highlighted the winter period (January to March) in the PFA year as being the most strongly associated with reconstructed PFA.

For those initial years, absolute changes in PFA were related to absolute changes in the environmental variable, rather than the conventional approach of considering that the environment mediates survival (Table 1). This was later modified with models that considered both environmental and spawner indices as explanatory variables for PFA abundance and used the appropriate multiplicative error structure (ICES 2001) that takes into consideration that habitat acts on PFA through survival rather than on absolute abundance. A linear form of the model fitted the natural log of PFA relative to the natural log of spawners and habitat variables (Table 1). The retention of the habitat variable in the models that included a spawning stock explanatory variable was justified on the basis of studies showing synchrony over wide geographic areas of survival rates and that the winter period appeared to be a critical stage for post-smolt survival and maturation (Scarnecchia 1989; Reddin and Shearer 1987; Friedland et al. 1993; Friedland et al. 1998). The lagged spawner variable used was an incomplete index of the spawning stock, calculated as the sum of spawners from four of the six geographic areas of eastern North America and excluded the contribution of estimated spawners from a large area of eastern North America (Gulf) for the reason that inclusion of the entire spawner component of North America weakened the association between PFA and lagged spawners (ICES 2001).

ICES also reported on evidence of decline in productivity of salmon in the marine part of the life cycle as shown by declines in return rates of smolts to anadromous adults at a number of index sites in the North Atlantic and sustained declines in returns to homewaters despite important reductions in marine fisheries. As well, in the continent wide models that incorporated the habitat and lagged spawner indices as explanatory variables, the relative proportion of the explained variance in PFA due to the habitat variable was declining relative to that of the lagged spawner variable. In the 2001 assessment using the PFA time series from 1978 to 1999, the lagged spawner variable alone accounted for 79% of the variance of the log transformed PFA values whereas the habitat variable alone only accounted for
# Contents

<table><tr><td>i</td><td>Executive summary</td><td>iii</td></tr><tr><td>ii</td><td>Expert group information</td><td>iv</td></tr><tr><td>1</td><td>Introduction</td><td>1</td></tr><tr><td>2</td><td>Terms of Reference</td><td>3</td></tr><tr><td></td><td>2.1 WKBSALMON – Benchmark Workshop on Atlantic Salmon (Salmo salar) in the North Atlantic</td><td>3</td></tr><tr><td>3</td><td>North Atlantic salmon: stocks, countries, and management units</td><td>5</td></tr><tr><td>4</td><td>Data review</td><td>7</td></tr><tr><td></td><td>4.1 North East Atlantic Commission (NEAC) Data</td><td>7</td></tr><tr><td></td><td>4.1.1 Annual time-series data</td><td>8</td></tr><tr><td></td><td>4.1.2 Biological characteristics</td><td>9</td></tr><tr><td></td><td>4.1.3 Updates to the NEAC data</td><td>10</td></tr><tr><td></td><td>4.1.4 Conservation Limits for NEAC</td><td>10</td></tr><tr><td></td><td>4.2 North American Commission Data</td><td>12</td></tr><tr><td></td><td>4.2.1 Stock units for North American Commission Area (NAC)</td><td>12</td></tr><tr><td></td><td>4.2.2 Data inputs for the PFA forecast and LCM model</td><td>15</td></tr><tr><td></td><td>4.2.3 Differences in the run-reconstruction to derive the stock unit inputs for the PFA model and for the LCM</td><td>17</td></tr><tr><td></td><td>4.2.4 Changes to the LCM inputs from the previous version</td><td>18</td></tr><tr><td></td><td>4.2.5 Biological characteristics</td><td>19</td></tr><tr><td></td><td>4.2.6 Conservation Limits for NAC</td><td>20</td></tr><tr><td></td><td>4.3 Mixed stock marine fisheries</td><td>24</td></tr><tr><td></td><td>4.3.1 Marine fisheries affecting only NAC stock-units</td><td>24</td></tr><tr><td></td><td>4.3.2 Marine fisheries affecting NAC and NEAC stock-units</td><td>25</td></tr><tr><td></td><td>4.3.3 Faroes fisheries catches and splits</td><td>34</td></tr><tr><td></td><td>4.3.4 West Greenland fisheries catches and splits</td><td>38</td></tr><tr><td></td><td>4.4 New Stock-units</td><td>41</td></tr><tr><td>5</td><td>Life Cycle Model</td><td>43</td></tr><tr><td></td><td>5.1 Background</td><td>43</td></tr><tr><td></td><td>5.2 A new stock assessment framework</td><td>43</td></tr><tr><td></td><td>5.3 Bayesian life cycle model</td><td>47</td></tr><tr><td></td><td>5.3.1 LCM spatial structure</td><td>47</td></tr><tr><td></td><td>5.3.2 Stage structure and variability of life histories</td><td>47</td></tr><tr><td></td><td>5.3.3 Hypotheses to help partition the sources of temporal variability when estimating transition rates</td><td>48</td></tr><tr><td></td><td>5.3.4 Data flow</td><td>49</td></tr><tr><td></td><td>5.4 MCMC simulation using Nimble</td><td>51</td></tr><tr><td></td><td>5.5 Model diagnosis and sensitivity analysis</td><td>52</td></tr><tr><td></td><td>5.5.1 Convergence of MCMC simulations</td><td>52</td></tr><tr><td></td><td>5.5.2 Model diagnosis</td><td>52</td></tr><tr><td></td><td>5.5.3 Sensitivity analysis</td><td>53</td></tr><tr><td></td><td>5.6 Multiple years forecast and provision of catch advice</td><td>54</td></tr><tr><td></td><td>5.6.1 The LCM is a natural tool to forecast</td><td>54</td></tr><tr><td></td><td>5.6.2 Propagation of uncertainty in the forecasts</td><td>54</td></tr><tr><td></td><td>5.6.3 Risk analysis framework for the West Greenland and the Faroes fishery</td><td>55</td></tr><tr><td></td><td>5.7 Outputs of the LCM</td><td>57</td></tr><tr><td></td><td>5.7.1 Hindcasting – Fitting the LCM to the time series of data</td><td>57</td></tr><tr><td></td><td>5.7.2 Forecasting and risk analysis</td><td>61</td></tr><tr><td></td><td>5.8 Comparison with the PFA modelling framework and benefits of the LCM</td><td>64</td></tr></table>
15% the variance of the log transformed PFA values (ICES 2001). In the following year's assessment with data from 1978 to 2000, the habitat variable alone accounted for only 11% of the variance of the log transformed PFA values with an increasing association between PFA and lagged spawners (ICES 2002).

In the 2003 assessment, with the closure of the commercial fisheries in Labrador in 1999, alternate estimates of spawners for Labrador had not been developed and the lagged spawner index that included Labrador was not available. An alternate lagged spawner index that included the five other regions was developed and used in the regression model for PFA. When this new index was used in the regression model, the overall model that included the habitat index was not significant (ICES 2003). However, an analysis of the sequence of PFA and the revised lagged spawner index revealed a temporal structure within the data set that had not appeared previously and that could not be accounted for by the model used in previous years. Two states of Atlantic salmon production become evident with a transition state from 1988 to 1990 (ICES 2003; Chaput et al. 2005). To capture this dynamic, a model that incorporated a break into two time periods, termed phases, was fitted to the data. The position of the change between the high production phase and the lower more recent production phase was initially set to 1989 as this PFA year was perceived as the midpoint in the slide from a low spawner index and high PFA abundance to a high spawner index and unchanged PFA abundance (ICES 2003; Chaput et al. 2005). When the PFA, lagged spawner and habitat index variables were fit with a phase shift model, the habitat variable was not significant but the lagged spawner variable with an intercept shift in the mean PFA levels was highly significant, accounting for 82% of the variance in log transformed PFA. However, to be used in a forecast context, an indication of the phase of productivity for the forecast year was needed. ICES (2003) used an independent approach outside the lagged spawer to PFA model to make a forecast of the productivity phase. Specifically, ICES indicated that it seemed reasonable to expect that productivity for the 2003 PFA would be in the lower phase, as observed over the last ten years. The approach taken to estimate this probability was to examine the historical changes in PFA from year t to year t+2, the two-year lag was used because current year PFA (i.e. 2002) was not available due to its dependence upon 2SW returns in the next year. Historical observations were used to estimate the possible values of PFA in the predicted year from the reconstructed PFA two years earlier to determine the probability of being in each phase of the two-phase regression. Consequently for the 2003 forecast of PFA, the probability of being in the high phase was estimated at 4.8% and the probability of being in the lower productivity phase was estimated as 95.2% (ICES 2003). The predicted PFA was a weighted combination of the two possible PFA distributions from two regressions, with weights determined by the probability of being in each phase. The two phase model for analyzing PFA and forecasting abundance was used by ICES for the subsequent years to 2010, including for multi-year advice in which the forecasts for 2009 and 2010 PFA years were based on the same models used for the 2008 PFA forecast with the probability of being in the low phase in 2009 and 2010 assumed to be the same as in 2008.

Alternate models that considered temporal changes in the mean productivity were also examined (ICES 2008) including a dynamic model, as described by Prévost *et al.* (2005). There is no functional dynamic implied between PFA and LS in this model other than the temporal dynamic that production rate ($α_y$ synonymous with $PFA_y/LS_y$) in the year of interest would likely be similar to the previous year. The production rate ($α_y$) was modelled as either simple random walk or as an autocorrelated random shift between two productive states. In the exploration of these models, the mid-point values of PFA were modelled as a lognormal function of mid-point values of lagged spawners. The results confirmed the previous conclusions (Chaput et al. 2005) in inferring that there had been a decrease in the productivity (PFA/LS) for the North American complex, beginning in 1989, continuing to decline into 1997, and remaining low thereafter (ICES 2008).

Forecasts of PFA for the fishery year of interest were derived using variants of models that always considered PFA at the continental scale as equivalent to an observation (Table 2). Some level of uncertainty regarding the relationship between PFA and the explanatory variables was eventually incorporated in the catch advice portion of the model by generating a number of data sets of estimated
<table><tr><td>5.8.1</td><td>Expected differences in forecast and risk analysis between life cycle and PFA models</td><td>64</td></tr><tr><td>5.8.2</td><td>Comparison of outputs of the new LCM and PFA models</td><td>64</td></tr><tr><td>6</td><td>Transparent Assessment Framework (TAF)</td><td>69</td></tr><tr><td>7</td><td>Review</td><td>71</td></tr><tr><td>7.1</td><td>Reviewers' Report</td><td>71</td></tr><tr><td>7.2</td><td>Reviewers' Recommendations</td><td>72</td></tr><tr><td>8</td><td>Recommendations/Issue List</td><td>76</td></tr><tr><td>9</td><td>References</td><td>79</td></tr><tr><td>Annex 1:</td><td>List of participants and meeting attendance</td><td>82</td></tr><tr><td>Annex 2:</td><td>Working Documents list</td><td>85</td></tr></table>
returns of 2SW salmon to North America (NR2.tot), catches of 2SW salmon in North America (NL2.tot) and catches of non-maturing 1SW salmon at Greenland (WG1nm.tot) and in North America (NL1nm.tot) based on random draws assuming uniform distributions of the input variables defined by minimum and maximum ranges from the run reconstruction. These simulated values of PFA, and eventually lagged spawners for the catch advice year of 2000, were used to summarize the distribution of the predicted PFA values from regression models adjusted to each stream of simulated data. Incorporation of measurement errors particularly in the predictor variable increased the uncertainty of the forecast. This is understandable because as the predictive variables become less informative about PFA, the most probable value of the PFA approaches the mean of the series. But this component of including uncertainty was not included implicitly in the inference component of the model.

Initially, the forecast of PFA was compared to the 2SW conservation requirements for eastern North America, adjusting for the losses due to natural mortality that would occur from the time of the PFA assessment to returns to homewaters (11 months of mortality). The risks of meeting the overall conservation requirement were thus provided using a risk analysis framework that considered the uncertainties in the PFA forecast and uncertainties in the characteristics of the fish in the fishery harvests.

ICES (2000) recognized the inherent risks of managing a mixed stock fishery while not accounting for stock structure particularly when the status of the individual stocks differed greatly. Initial attempts to rectify this consisted of adjusting the overall spawning requirement to account for the risk of meeting conservation requirements simultaneously in the six regions of North America (ICES 2000; Chaput 2004). This adjustment was the most optimistic scenario and assumed that rates of production were similar in all six stock areas. The reality was quite different as the stock status differed greatly among the regions with the expected returns of salmon to the USA and Scotia Fundy areas of recent years to be severely below their respective conservation requirements. The majority of the non-maturing 1SW salmon in the Northwest Atlantic in 2001 were expected to return principally to the Quebec, Gulf, Labrador and Newfoundland (ICES 2001). Ignoring these differences in anticipated relative production among regions and focusing on total abundance over regions did not provide a realistic assessment nor a useful analysis for guiding fisheries management.

In an attempt to rectify this, ICES (2002) partitioned the complex wide PFA forecast into potential regional returns based on the regional proportions of lagged spawners for the return year and assessed these regional returns against the region specific conservation requirements for 2SW salmon. Under estimated levels of 2SW spawning escapements, the majority of the non-maturing 1SW salmon in the Northwest Atlantic in 2001 were expected to return principally to the areas of Quebec, Gulf, Labrador and Newfoundland with very likely near zero chance for the Scotia-Fundy stock and zero chance for the USA stocks of meeting their region-specific 2SW spawner requirements. The partitioning of PFA to regions and returns to regions was done outside the stock dynamic model structure and in its approach assumed implicitly that there was one overall productivity dynamic common to all stocks from eastern North America.

Ultimately, ICES recognized the need to move to an alternate stock model that treated regions as specific components of the stock and recruitment dynamic which could be incorporated in a more cohesive and implicit structure with region-specificities in productivities and uncertainties. The model would implicitly include in the assessment of catch options the risk of achieving region specific spawner objectives.

## NAC PFA MODEL

The onus to model region specific abundance relative to region specific spawning requirements initiated the reflection of incorporating implicitly the stock structure at the scale of regions within a single model. Also, it was recognized that PFA and lagged spawner inputs used in the complex wide models by ICES were not observations in the true sense, having been estimated from a number of other data
# i Executive summary

WKBSalmon reviewed the implementation of a Life Cycle Model (LCM) for wild anadromous Atlantic salmon (*Salmo salar* L.) covering their natal north Atlantic range. The LCM is a time iterative, Bayesian hierarchical model incorporating salmon records of fifteen countries at 25 stock-units. It tracks salmon of two explicit sea-age streams, namely, one-sea-winter (1SW) and multi-sea-winter (MSW), stock unit specific smolt ages, numbers of salmon returning to stock-units, proportions maturing, survival at sea by month and stock unit specific post-smolt survival rates and proportion maturing at 1SW. Mixed-stock catches at West Greenland and Fa-bores, as well as those in North America, are designated to stock-units based on observed historic tag data, genetic identification and assumed harvest distributions.

The LCM will replace three Pre-Fisheries Abundance (PFA) forecast models, aligned to three management units, one eastern North America and two Northeast Atlantic European complexes of stock-units. The LCM enables a more comprehensive and consistent approach, accounting for migration and maturation of salmon by stock-unit and a hierarchical (over stock-units) modelling of post-smolt survival and proportion maturing in the first year at sea.

The LCM uses outputs from two “Run Reconstruction” models, one for each of eastern North America and Northeast Atlantic origin salmon. These processes catch data and exploitation rates and / or returns at stock-unit spatial scales to estimate returning numbers and catches of salmon by sea-age group. The LCM model uses a similar sea-age group structure for all stock-units resulting in a harmonized life cycle for Atlantic salmon from the North Atlantic.

The LCM forecasts estimates of returning salmon by stock-unit based on the post-smolt survival and proportion maturing parameters, forecast forward as a random-walk, from the most recent observations and accounting for “banked” maturing and non-maturing salmon. Fore-cast returns to stock-units may be compared to Conservation Limit (CL) reference points and “Spowner Escapement Reserves” (SERs – reference points prior to any marine fishing activities) at national and international levels to quantify the risk to the salmon stocks under different mixed-fisheries catch levels.

The LCM was found to provide estimates of stock status and forecasts in line with perceptions and previously used modelling frameworks and to be robust to a range of settings and uncertainties.
sources, each with associated uncertainties, and generally these uncertainties were not included at the complex wide modelling scale (Table 2).

ICES (2008) suggested that consideration be given to implicitly linking dynamics of multiple stages within a Bayesian modelling framework which can accommodate observation errors and parameter uncertainties. The regionally disaggregated model differs from the model used by ICES until then in the way observations are considered, the procedure for model fitting, and in the way inferences are drawn on the variables of interest. (Table 2)

In the case of Atlantic salmon for the ICES context, the 2SW spawners and the 2SW returns are the closest inputs that could be considered observations. Intermediate observations include the catches which are modelled as covariates acting as controls on the abundance of salmon at different points at sea and ultimately on returns to homewaters. In the region-disaggregated model approach, the PFA (recruitment) is a latent variable. i.e. a variable conditioned by several components directly influencing its distribution (catches in the marine environment, returns to rivers, natural mortality) but which cannot be observed directly. The PFA stage is particularly problematic as there are no stage specific indices available which can be used to draw inferences on its value, and the observations that link to it are distant in time and space, either the spawners that produce it or the returns to homewaters that result from it. In the region-disaggregated model, it is the returns of 2SW salmon to regions that are treated as the observations, which in concert with fisheries catches at earlier stages at sea and assumptions on natural mortality post-PFA stage condition the estimates of abundance at the PFA stage. The region-disaggregated model structure is illustrated in Figure 2.

The recruitment rate dynamic between lagged spawners and returns is also modeled differently in the region disaggregated model from that previously used by ICES. The two phase model used by ICES (described by Chaput et al. 2005) considers that there have been (and will be) two levels of recruitment rate experienced by the North American salmon complex. When the populations are in the low phase, they will either remain in the low phase or move to the high phase, there is no possibility of a further decline in recruitment rate or intermediate levels of recruitment rate. The region disaggregated model with a dynamic structure on the productivity parameter provides a more flexible structure that allows for increases or decreases over time regardless of the previous states of the populations (Prevost et al. 2005) although abrupt changes are not adequately detected because the annual changes are smoothed and the magnitude constrained by the relative changes estimated from the past.

## NAC REGION DISAGGREGATED PFA MODEL

The NAC PFA forecast model used by ICES to 2021 builds on the previous work and expertise developed by the ICES North Atlantic Salmon Working Group (ICES 2009, 2012). The purposes of the model are to:

* retrospectively estimate the NAC PFA prior to the marine fisheries on Atlantic salmon at Greenland and in the Newfoundland and Labrador sea fisheries based on "observed" lagged spawners, catches and returns to rivers (after marine fisheries), and

* to predict PFA for providing catch advice for the Greenland and Newfoundland and Labrador sea fisheries based on realized lagged spawners.

The PFA includes future 2SW fish only, referred to as 1SW non-maturing fish, and refers to the abundance prior to any sea fishery. It links the 2SW (lagged) spawner abundances in each of six regions to the subsequent 2SW returns to rivers in each of six regions, PFA being an intermediate and unknown state (latent variable). In the latest use of the model by the ICES WGNAS in March 2021, abundance prior to the fisheries is predicted for three years 2021 to 2023. These predicted abundances are used to provide catch advice for the fishery at West Greenland on 1SW non-maturing salmon in 2021 to 2023 and for the potential fisheries in North America on 2SW salmon when they return to homewaters for the years 2021 to 2024. The risk analysis and catch advice procedures have been described previously (Chaput et al. 2005; ICES 2012) and are not presented here.
## ii Expert group information

<table><tr><td>Expert group name</td><td>Benchmark Workshop on Atlantic Salmon (Salmo salar) in the North Atlantic (WKBSALMON)</td></tr><tr><td>Expert group cycle</td><td>Annual</td></tr><tr><td>Year cycle started</td><td>2023</td></tr><tr><td>Reporting year in cycle</td><td>1/1</td></tr><tr><td>Chair(s)</td><td>Jonathan White (Ireland)<br/>Tommi Perälä (Finland)</td></tr><tr><td>Meeting venue(s) and dates</td><td>15–17 November 2022<br/>20–23 June 2023 (online)<br/>23–27 October 2023 (ICES HQ, Copenhagen, Denmark)</td></tr></table>
## Materials and Methods

The North American stock complex is partitioned into six regions (k; Figure 1):

1. Labrador,

2. Newfoundland,

3. Quebec,

4. Gulf of St-Lawrence,

5. Scotia-Fundy,

6. USA

Outputs from the run reconstruction model for 2SW returns and 2SW lagged spawners (Rago 2001) by stock unit are used as inputs to the PFA forecast model (Figure 2).

The 2SW lagged spawners ($LS_{i,k}$) represent the sum of smolt age adjusted annual 2SW spawners by stock unit (k) and year (i) that would be expected to contribute to the recruitment at sea prior to the fisheries (PFA) for year i (Figure 3). $LS_{i,k}$ are not directly observed but are estimated from the run-reconstruction submodel. The probability distributions of LS and returns of 2SW salmon by stock unit are used as likelihood functions expressing comparative degrees of belief given the data and a probability model not explicitly specified in the current model. The probability distributions were drawn from the run reconstruction Monte Carlo simulations and assumed normal with known mean (LS.m) and precision (1/variance) (tau.LS). The use of this distribution as a likelihood function is equivalent to assuming a pseudo-observation equal to LS.m issuing from a sampling distribution with mean and precision equal to LS and tau.LS (Michielsens et al. 2008).

$$LS.m_{i,k} \sim N(LS_{i,k}, tau.LS_{i,k})$$

The $LS.m_{i,k}$ (mean) and tau.LS$_{i,k}$ (precision) were derived assuming the lagged spawner values were issued from a normal distribution characterized by the mean and standard deviation statistics from the run reconstruction Monte Carlo simulations of spawners and lagged spawners (Figure 4). For stock unit 6 (USA), the run reconstruction does not provide a dispersion for the Lagged spawners; the precisions (tau.LS[,6]) were drawn from a normal distribution assuming a fixed coefficient of variation of 0.01.

Returns of 2SW salmon back to the rivers of North America (NR2$_{i,k}$) are not directly observed but estimated with uncertainty (Figure 5). The run reconstruction model provides a probability distribution of NR2 by region, taken as comparative degrees of credibility of NR2, conditional on observed data and expertise. The way this expertise is used to link NR2 to the observed data (e.g. river counts) is not included in the current model. The NR2 probability distributions from run reconstruction are used as likelihood functions assumed to be normal with known mean NR2.m and precision tau.NR2. The use of this distribution as a likelihood function is equivalent to assuming to have one pseudo-observation equal to NR2.m issuing from a sampling distribution with mean and precision equal to NR2 and tau.NR2 (Michielsens et al. 2008).

$$NR2.m_{i,k} \sim N(NR2_{i,k}, tau.NR2_{i,k})$$

The $NR2_{i,k}$ (mean) and tau.NR2$_{i,k}$ (1/variance) were derived assuming the returns were issued from a normal distribution characterized by the mean and standard deviation of the Monte Carlo simulations of returns. For stock unit 6 (USA), the run reconstruction does not provide a dispersion for the Lagged spawners or the 2SW returns. The precisions (tau.LS[,6] and tau.NR2[,6]) were drawn from a normal distribution assuming a fixed coefficient of variation of 0.01.

## Modelling the lagged spawners to 2SW returns

The years are modeled independently conditionally on the lagged spawners and yearly productivity parameters (Figures 2, 3). The lagged spawners to PFA ratios (productivity) are modeled dynamically,
# 1 Introduction

WKBSalmon was organized with the primary purpose of reviewing, checking and consolidating a Bayesian state-space Life Cycle Model (LCM) representation of wild anadromous Atlantic salmon (*Salmo salar* L.) stocks covering their geographic range across the North Atlantic. This model has been developed through activities of members of the ICES Working Group on North Atlantic Salmon (WGNAS) with its first notable developments in the form of a single country life cycle example model founded around collaboration of the EU FP7 project ECOKNOWS (2010-2014).

In forecasting stock status, the WGNAS has to date followed a series of processes. Regional data compilation, for groups of countries / stock-units, is standardised and submitted to the Working Group. Data are then processed through American (North American Commission; NAC) and northern and southern European (respectively N-NEAC and S-NEAC: North East Atlantic Commission) "Run Reconstructions" (RR), which provide standardised data of returns, spawners, lagged eggs or lagged spawners for two sea-age classes, namely one-sea-winter (1SW) and multi-sea-winter (MSW). These were then subsequently used in NAC, N-NEAC and S-NEAC "Pre-Fisheries Abundance" (PFA) forecast models to develop ICES advice on fishing opportunities, last implemented in ICES (2021). Implementation of the LCM will move the hindcasting and forecasting elements of the assessments away from three independent PFA models to a single unified model (Figure 1.1).

<figure><img src="image_5.png" /><figcaption>**Figure 1.1.** Representation of North Atlantic Salmon assessment framework with (top) independent Pre-Fisheries Forecast models and (bottom) single unified North Atlantic Life Cycle Model.</figcaption></figure>

The LCM replaces the three PFA models with a single North Atlantic-wide hindcasting (based on historical observations) and forecasting approach. This model tracks salmon across the three North Atlantic Salmon Conservation Organization (NASCO) commissions – NAC, NEAC and
i.e. assuming they are sequentially dependent within a region and attempts to take into account the most significant sources of uncertainty. The DAG for the model is shown in Figure 3.

PFA is assumed to be proportional to lagged-spawners (LS), with i.i.d. lognormal errors, and is modeled separately for each region (k = 6). The first year in the time series (t) is 1978 for lagged spawners (due to the range of smolt ages 1 to 6 for NAC and the start of the spawner time series in 1970) and the last year of lagged spawner data is for the 2023 PFA year. In ICES (2021b), the PFA was modeled for 1978 to 2019 (the last PFA year for which returns of 2SW salmon have been estimated back to rivers in 2020).

$$PFA_{i,k} = \text{LogN}(PFA_{i,k}, \sigma.PFA^2)$$

$$\overline{PFA}_{i,k} = \log(LS_{i,k}) + a_{i,k} + \varepsilon_{i,k}$$

iid

$$\varepsilon_{i,k} \sim N(0, \sigma.PFA^2)$$

The total PFA is calculated as the sum of the regional PFA's (k = 6). The proportion of the total PFA in each region is calculated directly as:

$$p.PFA_{i,k} = PFA_{i,k} / PFA.tot_i$$

A non-informative prior is assumed for $\sigma.PFA^2$ ($1/\sigma.PFA^2 \sim \text{gamma}(0.01, 0.01)$).

The proportionality coefficient (log) $a_{i,k}$ between $LS_{i,k}$ and $PFA_{i,k}$ for each region, also called the productivity parameter, is modeled dynamically as a random walk with a year and stock unit residual variation ($\eta_{i,k}$) assumed multivariate normal (MVN). The variance covariance matrix ($\Sigma$) allows for correlations among stock unit productivity values reflecting that the fish share a common marine environment during part of their life cycle and that there are regional specificities in the evolution of the freshwater or the marine coastal environment.

$$a_{i+1,k} = a_{i,k} + \eta_{i,k}$$

iid

$$\eta_{i,k} \sim \text{MVN}(0, \Sigma)$$

The common yearly evolution of $a_i$ is the mean of annual $a_i$ across regions:

$$a_i = \text{mean}(a_{i,k})$$

This parameterization of the covariance of the proportionality coefficient is similar to the version of the model used by ICES (2015, 2018). The correlation matrix of $a$ among the regions is calculated from the covariance matrix.

## PFA to returns of 2SW fish to regions of North America

The catches in the commercial fisheries of West Greenland and the Newfoundland and Labrador commercial and FSC fisheries (NG1.tot, NC1.tot and NC2.tot) are not directly observed but estimated with error. The catches are converted to numbers of 1SW non-maturing and 2SW fish based on biological characteristics of the fish in the catch (Table 3). Their (prior) probability distributions are obtained from catch statistics according to a formal structure included in the current model.

The West Greenland fishery has two components: a reported catch and an unreported catch:

$$\text{WGHarv.Est}_i = \text{WGHarv}_i + \text{WGUnHarv}_i$$

The catch in weight (t) is converted into numbers of fish based on a sampled mean weight (kg):

$$\text{WGN.Est}_i = \text{WGHarv.Est}_i * 1000 / \text{WGMeanWt}_i$$
West Greenland Commission (WGC). It includes mixing of stocks at West Greenland and the Faroes, the two mixed stock fishing areas considered by NASCO. It considers two sea-age class groups, 1SW and MSW. The MSW age class is strictly calculated as fish spending two years at sea (2SW), however it may be considered a "plus-group", concordantly combining salmon of two, three and older first-time spawning age groups and repeat spawners. Predominantly, numbers relate to 2SW salmon but will be referred to as MSW.

Outputs of the LCM are in line with the previously employed Pre-Fisheries Abundance (PFA) forecast models, providing for NEAC and NAC, by country and assessment units, assessment time-series and 5 years forecasts (the current and previous years – necessary to forecast owing to data requirements in back calculations of 2SW salmon – and forward three years) of total PFA, PFA maturing (1SW), PFA non-maturing (MSW), Productivity (post-smolt survival), Proportion maturing as 1SW, Returns of 1SW, Returns of MSW and eggs in returns/spawners of 1SW, MSW and all sea-age groups.

Advantages of the LCM are that it provides a single, unified assessment framework, data-
framework and workflow and links the productivity and maturation processes at sea
hierarchically among all stock-units. In addition, it provides a more realistic representation of
the life-cycles and interactions of salmon stocks and fisheries that share a common albeit large
marine environment and improved stock-unit biology (freshwater survival rates, biological
characteristics).

During the benchmark process data were reviewed and updates were incorporated as
appropriate.
Only a portion of the catch at West Greenland is of North American origin (pNAC.est) and of non-maturing 1SW salmon (p1SWNAC):

$$pNAC.est_i \sim \text{uniform}(\text{WGPropNACMin}_i, \text{WGPropNACMax}_i)$$

(for West Greenland fishery years 1978 to 1999, 2001; based on discriminant functions of continent of origin scale characteristics)

$$pNAC.est_i \sim \text{beta}(\text{WGSampleNAC}_i, \text{WGSampleNEAC}_i)$$

(for West Greenland fishery years 2000, 2002 to present; based on genetic sampling)

$$\text{NG1.tot}_i = \text{WGN.Est}_i * \text{pNAC.est}_i * \text{p1SWNAC}_i$$

For the Labrador and some of the Newfoundland fisheries (Table 4), 1SW salmon are present in the large salmon category, a portion of which are considered to be 1SW non-maturing. As well, it is assumed that some 1SW salmon in the small salmon catch category are also 1SW non-maturing.

For the fisheries in Labrador and SFA 3 to 7, the catch of 1SW non-maturing was estimated as:

$$\text{NC1.tot}_i = f_{\text{imm}} * (\text{LB\_Com\_Sm}_i + \text{NF3to7Com\_Sm}_i + (\text{LB\_Com\_Lg}_i + \text{NF3to7Com\_Lg}_i) * q) + af_{\text{imm}}*(\text{Nsm\_LBFSC}_i + \text{NLg\_LBFSC}_i * q)$$

with $f_{\text{imm}} \sim \text{uniform}(0.1 \text{ to } 0.2)$, $af_{\text{imm}} \sim \text{uniform}(0.05 \text{ to } 0.1)$, $q \sim \text{uniform}(0.1, 0.3)$.

For the fisheries in Newfoundland and Labrador (SFA 1 to 14B), the catch of 2SW salmon was estimated as:

$$\text{NC2.tot}_i = (\text{LB\_Com\_Lg}_i + \text{NF3to7Com\_Lg}_i + \text{NLg\_LBFSC}_i) * (1 - q) + \text{NF8to14A\_Lg}_i$$

with $q$ as above ~ uniform (0.1, 0.3)

Escapement (N1ᵢₖ) from the Greenland (NG1.totᵢ) and NFLD/Labrador (NC1.totᵢ) fisheries on non-maturing 1SW salmon are calculated by subtracting catches of non-maturing 1SW fish from the regional PFAs apportioned according to p.PFAᵢₖ (i.e. each region is exploited at the same rate).

$$\text{N1}_{i,k} = \text{PFA}_{i,k} - (\text{NG1.tot}_i + \text{NC1.tot}_i) * \text{p.PFA}_{i,k}$$

Exploitation rates of the regional stocks for any of the fisheries are estimated from the catch and the corresponding regional abundances at the time of the fisheries. Exploitation rate on 1SW non-maturing at West Greenland:

$$\text{ER.WG}_{i,k} = \text{NG1}_{i,k} / \text{PFA}_{i,k}$$

Exploitation rate on 1SW non-maturing salmon in North America:

$$\text{ER.C1}_{i,k} = \text{NC1}_{i,k} / \text{PFA}_{i,k}$$

Returns of 2SW fish (N2.1ᵢₖ) back to the coast of North America take into account natural mortality M1 over 10 months, the average delay between the Greenland and NFLD/Labrador fisheries on 1SW non-maturing fish and the arrival of the 2SW fish along the coast of North America. M1 is assumed to be iid across years according to a normal distribution with mean 0.03 and 95% interval [0.02, 0.04].

$$N2.1_{i,k} = N1_{i,k} * s_i$$

with $s_i = \exp^{-M1 * 10}$ and M1 ~ N(0.03, 2.5*10⁻⁵)

Without this narrowing of the potential range of variation of M1, there is a confusion between PFA and M1. This is a very strong a priori hypothesis that assumes no temporal variation in the average M1 such that all the temporal variation contained in the LS to 2SW returns must be accounted by the evolution over time of the $\alpha$ parameter. In addition, the smaller the value of $\alpha$ (a priori), the stronger the influence (a priori) of NC1 and NG1 on the returns to North America.
## 2 Terms of Reference

### 2.1 WKBSALMON – Benchmark Workshop on Atlantic Salmon (*Salmo salar*) in the North Atlantic

2022/2/FRSG47 A Benchmark Workshop on Atlantic salmon (*Salmo salar*) in the North Atlantic, chaired by External Chair Tommi Perälä (FI) and ICES Chair Jonathan White (IE) and attended by invited external experts Chris Legault (USA) and Grant Hanson (USA). The benchmark will be established as a series of workshops that will work to:

1. scope the work and create a workplan for the benchmark;

a) update the BWKSalmon ToRs with chairs and reviewer names, workshop dates for ToRs 2 and 3;

b) complete Table 1

2. compile data and evaluate quality;

3. develop the assessment and associated tools to provide advice;

4. document all methods and data used and agreed upon by the benchmark in the stock annex; and

5. develop recommendations for future improvements of the assessment methodology and data collection.

Re: ToR 1. BWKSalmon will meet at ICES HQ 15–17 November 2022 for a scoping workshop. This scoping workshop will work to identify not only the scope of work for the benchmark, but it will also lay out the work plan and schedule for subsequent ICES workshops that are part of this benchmark and identify relevant participants and external experts to contribute to this work. Dennis Ensing (UK) and Etienne Rivot (France) will chair this meeting.

Re: ToR 2. BWKSalmon will conduct a data evaluation workshop, which may include the publication of an ICES [data call](https://datacall.icespub.org/)<fnref n="1" /> to support this work. The workshop will be held 20th-23rd June 2023 online. This workshop will consider the quality of input data proposed for use in the assessment, make a proposal to the benchmark on the use and treatment of data for each assessment, including discards, surveys, life history, fishery-dependent, recreational, etc. Stakeholders are invited to contribute data (including data from non-traditional sources) and to contribute to data preparation and evaluation of data quality.

Re: ToR 3. A methods workshop will be held 23–27 October 2023 at ICES HQ in Copenhagen, with hybrid meeting access for all participants. In preparation for the methods workshop, working documents and input data should be delivered by the participants following the DEWK (data evaluation workshop) and at least 14 days in advance of the methods workshop. The methods workshop should agree to and thoroughly document the most appropriate method for conducting the stock assessment, the method and values for fisheries and biomass reference points that follow the best available science and are in line with ICES guidelines (see the latest Technical guidance on reference points).

As part of the methods workshop, knowledge about environmental drivers, including multispecies interactions and ecosystem impacts should be integrated in the methodology. A full suite of diagnostics (regarding data, retrospective behaviour, model fit, predictive power

<footnote n="1">¹ ICES (2023). WKBSALMON-2-2023: Data submission for ICES Benchmark Workshop on North Atlantic salmon stocks.. Data Calls. Report. https://doi.org/10.17895/ices.pub.23098502.v1</footnote>
## Regional apportioning of the 2SW catches in Newfoundland, Labrador and St. Pierre and Miquelon fisheries

Based on expert opinion, the exploitation rates of 2SW of the regional groups in North America differed within the fisheries of Newfoundland and Labrador. Specifically, the commercial and FSC fisheries of Labrador were assumed to exploit a higher proportion of Labrador origin 2SW salmon than would be the case based on the relative abundance of PFA to that time and those fisheries (Bradbury et al. 2015). The following assumptions were made to apportion the catches of 2SW salmon in these fisheries to each region.

The fisheries of Labrador (SFAs 1, 2, 14B; Table 4) were assumed to be comprised of the following proportions:

* $pLab_i \sim \text{uniform}(0.6, 0.8)$ for $i = 1971$ to 1997

* $pLab_i \sim \text{uniform}(0.9, 1.0)$ for $i = 1998$ to present

* the non-Labrador portions of the catches were apportioned as $pPFA'_k$ for the other five regions ($pPFA'_{i,k} = pPFA_{i,k} / \text{sum}(pPFA_{i,k}, \text{excluding Labrador})$

The commercial fisheries harvests of Newfoundland (Table 4) were assumed to be comprised of the following regional proportions:

* the commercial fisheries of Newfoundland in SFA 3 to 7 (northeast coast) were apportioned to the regions as $pPFA_{i,k}$ (i.e. including Labrador)

* the commercial fisheries of Newfoundland in SFA 8 to 14A (south and west coast) were apportioned to the regions as $pPFA'_{i,k}$ (i.e. no Labrador origin fish in these fisheries)

The estimated catches of large salmon from the St. Pierre and Miquelon fisheries (SPMC2; Table 3) were apportioned to the regions as $pPFA'_{i,k}$ (i.e. no Labrador origin fish in these fisheries) (Bradbury et al. 2016a).

Escapement from the North American coastal marine fisheries ($N2.2_{i,k}$) is obtained by subtracting the 2SW catch ($NC2_{tot_{i,k}}$) from the 2SW returns ($N2.1_{i,k}$).

$$N2.2_{i,k} = N2.1_{i,k} - NC2_{i,k} - SPMC2_{i,k}$$

Exploitation rates of the regional stocks for any of the fisheries are estimated from the catch and the corresponding regional abundances at the time of the fisheries.

Exploitation rate on 2SW salmon in North America (Newfoundland and Labrador) fisheries:

$$ER.C2_{i,k} = NC2_{i,k} / N2.1_{i,k}$$

Returns of 2SW salmon (NR2) back to the rivers of North America take into account natural mortality (M2) over 1 month, the average delay between the NFLD/Labrador fishery and the entry in rivers for the 2SW fish.

$$NR2_{i,k} = N2.2_{i,k} * s_i$$

with $s_i = \exp^{-M2 * 1}$ and $M2 \sim N(0.03, 2.5*10^{-5})$

## FORECASTS AND CATCH OPTION SCENARIOS (ICES 2021)

ICES (2021b) provided a forecast for the year 2020 (maximum lagged spawner year (2023) – 3) for which the lagged spawners, and the catches of 1SW fish in the Greenland and NFLD/Labrador fisheries have been observed but the catch in the NFLD/Labrador fishery and the river returns of 2SW have not yet been observed. This part of the model can be used to provide catch advice on 2SW salmon for the NFLD/Labrador fishery in the year 2021.
etc.) should be examined as a whole to evaluate the appropriateness of any model developed and proposed for use in generating advice.

Please note the work presented in ICES meetings WGNAS, WKSalModel, WKSalmon1 and WKSalmon2 that was done in preparation of this benchmark, originally named WKSalmon3; the ICES data call<fnref n="2" /> issued from work done in WKSalmon2 will thus be taken up as part of this benchmark.

Re: ToR 4. The method for conducting the short-term forecast and determination of fishing mortality and biomass reference points should also be included as part of this work. This can be done through the stock annex and in the Transparent Assessment Framework (TAF).

If additional time is needed to agree to reference points and the short-term forecast, the benchmark can agree to additional meeting days.

If no analytical assessment method can be agreed, then an alternative method (the former method, or following the ICES data-limited stock approach see WKLIFE X (https://doi.org/10.17895/ices.pub.5985) should be put forward by the benchmark.

The Benchmark Workshop will report for the attention of ACOM by 17 November 2023.

<table><caption>**Table 1.** The benchmark scope. To be completed by the WKBsalmon scoping meeting. Identify the people/institutes responsible for assessments and data as well as the objective of the benchmark for Atlantic salmon in each commission area. If the benchmark will not conduct work for Atlantic salmon in a commission area, it should be stated here.</caption><thead><tr><th>Salmon Assessment Areas</th><th>Stock leaders*</th><th>ICES stock category and assessment method</th></tr></thead><tbody><tr><td>Atlantic salmon (Salmo salar) from North America <a href="#">sal.nac.all</a></td><td><strong>Assessment:</strong> Institut Agro<br>DECOD/DFO Science<br><strong>Data:</strong> DFO Science/ NOAA<br>Other:</td><td>Category 1<br>Analytical model, run-reconstruction models and Bayesian forecasts, taking into account uncertainties in the data.<br>Benchmark objective to transition to LCM</td></tr><tr><td>Atlantic salmon (Salmo salar) in Northeast Atlantic and Arctic Ocean <a href="#">sal.neac.all</a></td><td><strong>Assessment:</strong> Institut Agro<br>DECOD/ NIAN/ Marine Institute/ Cefas<br><strong>Data:</strong> NIAN/ Marine Institute/ Cefas/ DFO Science/ NOAA<br>Other:</td><td>Category 1<br>Analytical model, run-reconstruction models and Bayesian forecasts, taking into account uncertainties in data<br>Benchmark objective to transition to LCM</td></tr><tr><td>Atlantic salmon (Salmo salar) in Subarea 14 and NAFO division 1 (east and west of Greenland) <a href="#">sal.wgc.all</a></td><td><strong>Assessment:</strong> Institut Agro<br>DECOD/ DFO/ NOAA Marine Institute/ Cefas<br>NIAN/ DFO/ Marine Institute/ Cefas<br><strong>Data:</strong> NIAN/ Marine Institute/ Cefas/ DFO Science/ NOAA<br>Other:</td><td>Category 1<br>Analytical model, run reconstruction models and Bayesian forecasts, taking into account uncertainties in the data.<br>Benchmark objective to transition to LCM</td></tr></tbody></table>

<footnote>* Note these classifications do not align with the assessment approach. Both “Assessment” and “Data” have been aligned to the primary organisations compiling data and running assessment elements to date and do not constitute a definitive list. Owing to the crossover of data and assessment, the application of RRs and the LCM is very much a team effort. Responsibilities will be detailed in the WGNAS 2024/2025.</footnote>

<footnote n="2">² ICES. 2023. Data call - WKSALMON-2023 Data submission for selected stocks in support of WKSalmon3, WKBSalmon and WGNAS. https://doi.org/10.17895/ices.pub.22274884</footnote>
Modelling for the years Y-2 (2021) to Y (2023), for which only the lagged spawners have been observed, is used to forecast PFA abundance by region and to provide catch advice for the Greenland and the NFLD/Labrador fisheries. River returns are predicted conditionally on a catch option for the Greenland fishery in year i and for the NFLD/Labrador fishery in the year i and i+1. Greenland catch options are expressed in weight (t) and a sharing arrangement for North America and West Greenland of 60:40 (effectively means that for any catch option examine for West Greenland, the catch used in the risk analysis is raised by 2.5 (WGcatch/0.4)).

Risk analysis is based on the management objectives being simultaneously achieved in the six regions (ICES 2021b). The biological characteristics of the salmon in the fishery at West Greenland are estimated based on the characteristics of the most recent five years (Table 3). Biological characteristics for the fishery are drawn independently from a uniform distribution between the minimum and maximum values of the recent five years.

## RETROSPECTIVE ANALYSIS OF MODEL

The forecast abundances for PFA and the productivity parameter for the forecast years 2018 to 2020 (from ICES 2018) were contrasted with the reconstructed values based on the 2SW returns to the six regions up to 2020. The comparison that was conducted by ICES (2021b) is presented in this section.

## RESULTS AND DISCUSSION

Lagged spawners overall for NAC have generally been less than half the 2SW conservation limit for NAC (Figure 4). The lowest lagged spawner values were estimated during the 2003 to 2013 PFA years, with a slight improvement in abundance for the 2015 to 2016 and higher values for the 2020 to 2023 PFA years. The improvements in 2SW spawners in Labrador during 2013 to 2017 are now accounted for in the lagged spawners and these are the major contributors to the increased number of lagged spawners for NAC in the 2020 to 2023 PFA years.

Estimates returns of 2SW salmon to each region and overall for NAC for the years 1971 to 2020 (PFA years 1970 to 2019) are shown in Figure 5. Returns of 2SW salmon to rivers (after marine fisheries) exceeded the region-specific 2SW CLs at various times in the past, with exception to Labrador for which returns have only exceeded 2SW CL since 2012. The returns of 2SW salmon to US have never exceeded the 2SW CL for the region (29,990s fish) but exceeded the management objective for 2SW salmon in a few years in the 1980s (Figure 5).

### PFA TO LS PRODUCTIVITY

The productivity coefficient (log of PFA to LS) was highest in most regions prior to 1990 (PFA year) and decreased in all regions to reach the lowest values in the mid 1990s and early 2000s (Figures 6 and 7). Productivity coefficient values near zero or negative (a value of zero means the number of fish produced at the PFA stage equals the number of lagged spawners that produced them whereas a negative value means the PFA estimate was less than the lagged spawners) were estimated for Labrador and Newfoundland in the early 2000s, for Gulf during 1998 to 2000, and for Scotia-Fundy during the 1990s and again in the mid-2010s PFA year. The most recent year values (2019 PFA year) are positive for all regions (Figures 6 and 7).

The productivity coefficient for NAC overall was negative in 2001 and improved from that point onward but remains at values less than half those estimated between 1978 and 1988 PFA years (Figures 7 and 8).

There are weak correlations between the regional productivity parameters (Table 5).

### PFA ESTIMATES

Estimated abundance at the PFA stage (August 1 of the second summer at sea) by region show similar temporal trends of higher abundance in the late 1970s through the 1980s, with a rapid decline in the
## 3 North Atlantic salmon: stocks, countries, and management units

Atlantic salmon (*Salmo salar* L.) is an obligatory freshwater spawner. Anadromous (populations with life stages that migrate to the marine environment for part of their life cycle) Atlantic salmon spawn and occupy more than 2400 rivers in countries bordering the North Atlantic. Juvenile salmon may reside in rivers for 1 to as many as 8 years before migrating to the ocean as smolts to complete their growth and maturation process. Smolt ages increase with latitude on both sides of the North Atlantic (Metcalfe and Thorpe 1990). Many salmon from the Northeast Atlantic migrate to feeding grounds off the Faroes and the Norwegian Sea, overwinter and either return as 1SW salmon or migrate to feeding grounds around West Greenland or the Irminger and Barents Sea returning after 2, 3, 4 and even up to 6 winters at sea. As with smolt ages, older sea-ages and repeat spawners (both consecutive and alternate repeat spawner strategies) are generally more common in northern rivers of origin. Salmon from the Northwest Atlantic undergo feeding migrations to the Labrador Sea, West Greenland and in some cases into the Northeast Atlantic into areas proximate to the Faroe Islands sea-age

Countries, management and assessment units are aligned with North America (NAC), southern Europe (S-NEAC) and northern Europe (N-NEAC) stock complexes used by ICES and NASCO and (Figure 3.1).

The 25 stock-units are grouped within three large stock complexes:

* 6 stock-units for the North American continental stock group (NAC): Labrador, Newfoundland, Quebec, Gulf, Scotia-Fundy, USA;

* 8 stock-units for the Southern European continental stock group (S-NEAC): France, UK England and Wales, Ireland, UK Northern Ireland - FO, UK Northern Ireland - FB, UK Scotland East, UK Scotland West, Iceland South-West;

* 11 stock-units for the Northern European continental stock group (N-NEAC): Iceland North-East, Sweden, Norway South-East, Norway South-West, Norway Middle, Norway North, Finland, Russia Kola Barents, Russia Kola White Sea, Russia Arkhangelsk Karelia and Russia River Pechora.

The N-NEAC is further separated in two sub-complexes to consider differences in the migration routes (which in particular results in different availability of the fishes at the Faroes fisheries):

* The southern part of the N-NEAC (NNEAC-south), that comprises Iceland North-East, Sweden, Norway South-East, Norway South-West and Norway Middle.

* The northern part of the N-NEAC (NNEAC-north), that comprises Norway North, Finland, Russia Kola Barents, Russia Kola White Sea, Russia Arkhangelsk Karelia and Russia River Pechora.

Note that Netherland, Germany, Spain and Portugal (all being part of the Southern European complex (S-NEAC) and Denmark (possibly S-NEAC but to be determined) are not considered in the current version of the assessment model because no complete series of data are currently available. Salmon stocks from the Inner Bay of Fundy (Canada) are also not considered within the current version of the assessment as these populations are assumed to not migrate to distant waters.
late 1980s to early 1990s (Figure 9), with exception of Newfoundland for which PFA estimated
abundance declined in the late 1990s to early 2000s. There is an increase in the PFA to 2014 for
Labrador resulting directly from the increased 2SW lagged spawners and increasing productivity but the
subsequent PFA abundance declined associated with a decline in the productivity (Figure 6). PFA
declined and remains near historical lows in all other regions (Figure 9).

The regional contributions to the overall NAC PFA were relatively stable over the period 1980 to 2008 with over 70% of total PFA contributed by Quebec and Gulf regions, followed by Labrador with over 20% of the overall PFA (Figure 10). The Scotia-Fundy region contributed as much as 20% of the PFA for the 1984 PFA year but through the 2000s, has represented less than 5% of the total PFA and the US has never represented more than a few percentage of the total (Figure 10). The proportion of NAC PFA has increased substantially for Labrador since 2012 (Figure 10).

Forecasts of productivity and PFA for PFA years 2021 to 2023

The productivity parameter used in the forecast is the value derived from the last year in the model, with increasing uncertainty for each year of the forecast.

The overall productivity estimate for NAC in the most recent year PFA (2019) increased to a high positive value (median = 0.65; 1.9 fish at the PFA stage per lagged spawner) equal to that estimated previously during the 2007 to 2009 PFA years (Figure 8). By region, the most recent year value for the productivity was improved relative to the previous decade for Quebec, Gulf, Scotia-Fundy and USA while it remained low for Labrador or equal to values from the previous decade for Newfoundland. In all regions, the productivity value is low but positive compared to the estimates of the 1980s (Figures 6 and 7).

For 2021 to 2023 PFA years, the 5th percentiles of the posterior distributions of the regional PFAs are less than the management objective reserves for Scotia-Fundy and USA. In addition, the 25th percentiles are below the objectives for Gulf (Figure 9). For NAC overall, the predicted values (25th percentile) for 2021 to 2023 are all substantially below the 2SW CL reserve (CL corrected for 10 months of M = 0.03 per month; Figure 8). The forecasts have very high uncertainty and the uncertainties increase as the forecasts move farther forward in time.

RETROSPECTIVE ANALYSIS OF MODEL

In 2018, the ICES Working Group provided forecasts of the regional productivity parameters and the
regional specific PFAs based on the regional lagged spawners. The productivity parameter used in the
forecast is the value derived from the last year in the model, with increasing uncertainty for each year
of the forecast. In the 2018 assessment, the productivity parameter used to forecast the 2018 to 2020
PFA years was negative for three regions (Gulf, Scotia-Fundy, USA), positive and at low values for
Quebec and Newfoundland, and high for Labrador (ICES 2018; Figure 11). The returns of 2SW salmon in
2018 to 2020 were slightly higher than expected in all regions except Labrador and the realized
productivity for the 2017 to 2019 PFA years was higher than predicted in 2018 (Figure 12). As a result
the estimated regional PFA values were lower in Labrador for the 2017 to 2019 PFA years and slightly
higher in all the other regions (Figure 13). The larger overestimate for Labrador relative to the other
regions resulted in a lower PFA value for NAC for those years than forecast in the 2018 assessment. Due
to the large uncertainty associated with the forecast values, the estimated PFA values for 2017 to 2019
were within the 95% confidence intervals of the forecast values.

The previous advice provided by ICES (2018) indicated that there were no mixed-stock fishery catch
options on the 1SW non-maturing salmon component for the 2018 to 2020 PFA years and the 2021
assessment confirmed that advice.
<figure><img src="image_6.png" /></figure>

Figure 3.1. The 25 stock-units considered in North Atlantic. Stock-units of North America: NFLD=Newfoundland, GF=Gulf, SF=Scotia-Fundy, US=USA, QB=Quebec and LB=Labrador; Stock-units of Southern Europe (S-NEAC): IR=Ireland, E&W=England&Wales, FR=France, E.SC=Eastern Scotland, W.SC=Western Scotland, N.IR=Northern Ireland FO (Foyle bassin) and FB (DAERA (Department of Agriculture, Environment and Rural Affairs) region; note the split between FO and FB is not represented on the map), IC.SW=South-West Iceland; Stocks units in Northern Europe (N-NEAC): FI=Finland, IC.NE=North-East Iceland, NO.MI=Middle Norway, NO.NO=North Norway, NO.SE=South-East Norway, NO.SW=South-West Norway, RU.AK=Russia Arkhangelsk Karelia, RU.KB=Russia Kola Barents Sea, RU.KW=Russia Kola White Sea, RU.RP=Russia River Pechora, SWD=Sweden. Germany, The Netherlands, Denmark, Spain and Portugal are not included in the model. Pink ellipses indicate the main fisheries at sea operating on mixed stocks: Faroes, West Greenland, Labrador and Newfoundland (LAB/NFLD) and Saint Pierre and Miquelon (SPM).
REFERENCES

Bradbury, I.R., Hamilton, L.C., Rafferty, S., Meerburg, D., Poole, R., Dempson, J.B., Robertson, M.J., Reddin, D.G., Bourret, V., Dionne, M., Chaput, G., Sheehan, T.F., King, T.L., Candy, J.R., Bernatchez, L. 2015. Genetic evidence of local exploitation of Atlantic salmon in a coastal subsistence fishery in the Northwest Atlantic. Canadian Journal of Fisheries and Aquatic Sciences, 72: 83-95.

Bradbury, I.R., Hamilton, L.C., Chaput, G., Robertson, M.J., Goraguer, H., Walsh, A., Morris, V., Reddin, D., Dempson, J.B., Sheehan, T.F., King, T., Bernatchez, L. 2016a. Genetic mixed stock analysis of an interceptory Atlantic salmon fishery in the Northwest Atlantic. Fish. Res. 174: 234-244.

Bradbury, I.R., Hamilton, L.C., Sheehan, T.F., Chaput, G., Roberton, M.J., Dempson, J.B., Reddin, D., Morris, V., King, T., and Bernatchez, L. 2016b. Genetic mixed-stock analysis disentangles spatial and temporal variation in composition of the West Greenland Atlantic Salmon fishery. ICES J. Mar. Sci. 73: 2311-2321.

Chaput, G. 2004. Considerations for using spawner reference levels for managing single and mixed-stock fisheries of Atlantic salmon. ICES Journal of Marine Science, 61: 1379-1388.

Chaput, G. 2012. Overview of the status of Atlantic salmon (*Salmo salar*) in the North Atlantic and trends in marine mortality. ICES Journal of Marine Science, 69: 1538-1548.

Chaput, G., Legault, C. M., Reddin, D. G., Caron, F., and Amiro, P. G. 2005. Provision of catch advice taking account of non-stationarity in productivity of Atlantic salmon (*Salmo salar*) in the Northwest Atlantic. ICES Journal of Marine Science, 62: 131-143.

Crozier, W.W., Potter, E.C.E., Prevost, E., Schon, P.J., and O'Maoileidigh, N. 2003. A coordinated approach towards the development of a scientific basis for management of wild Atlantic salmon in the North-East Atlantic (SALMODEL). Queens University of Belfast, Belfast.

ICES. 1984. Report of the Working Group on North Atlantic Salmon. ICES CM 1984/Assess: 16, 54 pp.

ICES. 1994. Report of the Working Group on North Atlantic Salmon. Reykjavik, 6-15 April 1994. ICES, Doc. CM 1994/Assess: 16, Ref. M, 182 pp.

ICES. 1995. Report of the North Atlantic Salmon Working Group. Copenhagen, 3-12 April 1995. ICES CM 1995/Assess:14, Ref. M.

ICES. 1996. Report of the Working Group on North Atlantic Salmon. Moncton, Canada. 10-19 April 1996. ICES CM 1996/Assess:11, 227 pp

ICES. 1997. Report of the Working Group on North Atlantic Salmon. ICES CM 1997/Assess:10.

ICES. 1998. Report of the Working Group on North Atlantic Salmon. Galway, Ireland, 1-10 April 2008. ICES CM2008/ACOM:18. 236pp.

ICES 1999/ACFM:14 Report of the Working Group on North Atlantic Salmon. Québec City, Canada, ICES CM 1999/ACFM:14, 288 p.

ICES. 2000. Report of the Working Group on the North Atlantic Salmon. ICES Headquarters, Copenhagen, April 3-13. ICES CM 2000/ACFM: 13. 301 pp.

ICES. 2001. Report of the Working Group on North Atlantic Salmon. Aberdeen, 2-11 April 2001. ICES CM 2001/ACFM: 15, 290 pp.

ICES. 2002. Report of the Working Group on North Atlantic Salmon. ICES Headquarters, Copenhagen, 3-13 April 2002. ICES CM 2002/ACFM: 14, 299 pp.

ICES. 2003. Report of the Working Group on North Atlantic Salmon. ICES Headquarters, Copenhagen, 31 March-10 April 2003. ICES CM 2003/ACFM: 19, 297 pp.
# 4 Data review

Atlantic salmon are native to the temperate and subarctic regions of the North Atlantic Ocean and there are over 2000 rivers draining into the North Atlantic that support the fish, about 1500 of which discharge into the Northeast Atlantic and 900 in the Northwest Atlantic. In this area, salmon distribution extends from northern Portugal (41.87°N), to Iceland, to north eastern Russia (71.06°N, Norway), while in the Northwest Atlantic, the species ranges from northeastern USA 41.29°N) to northern Canada (Ungava Bay; 58.78°N). Atlantic salmon from the North Atlantic are distinct from salmon populations of rivers of the Baltic Sea, are subject to different fisheries and are managed by different Regional Fisheries Management Organisations (RFMO); the North Atlantic salmon are of interest to the North Atlantic Salmon Conservation Organisation (NASCO).

Large rivers and their tributaries can support several genetically distinct populations; however, it is not always possible to demarcate clear population boundaries within a river and managing stocks and fisheries at this level of detail would be very complex. Thus, while there is a need to protect the sustainability of these units, the primary management unit (e.g. for reporting catch statistics and regulating fishing) is generally taken to be the river stock, comprising all fish originating from eggs laid within the river.

Atlantic salmon would, ideally, be assessed and managed on the basis of river-specific stock-units. In reality, a small proportion (generally < 25%) of the rivers with salmon populations in the North Atlantic are so assessed and consequently, stock status for NASCO is assessed at broader regional, national and subcontinental scales.

Data for assessment of North Atlantic Salmon by the WGNAS are provided by member countries. Data are provided aggregated to the level of stock-units (Figure 3.1) within countries by the national competent authorities.

The opportunity was provided through the Benchmark before the June 2023 meeting for National laboratories to review and update values prior to model implementation in 2023. This process also provided the opportunity to consider adding other country/ stock-units to the assessment.

## 4.1 North East Atlantic Commission (NEAC) Data

Data from the North East Atlantic Commission are aggregated to 19 stock-units across the N-NEAC and S-NEAC stock complexes (Table 4.1). A Run Reconstruction model is used to derive numbers of returns to each stock unit which, together with catches for each stock unit, comprise the main NEAC inputs to the LCM.

The RR model was originally used to provide inputs into the PFA forecasting model and is detailed in Potter et al. (2004). In addition to returns, the model derives PFA estimates and spawner abundance estimates, which are not required by the LCM. For stock-units that do not have nationally derived conservation limits (CLs), the RR model derives CLs through a 'pseudo' stock-recruitment relationship (Potter et al. 1998). The inputs to the RR model comprise annual time-series data and multi-annual data.
ICES. 2004. Report of the Working Group on North Atlantic Salmon. Halifax, Canada 29 March – 8 April. ICES CM 2004/ACFM:20. 286 pp.

ICES. 2005. Report of the Working Group on North Atlantic Salmon. Nuuk, Greenland 5 March – 14 April. ICES CM 2005/ACFM:17. 290 pp.

ICES. 2006. Report of the Working Group on North Atlantic Salmon. ICES Headquarters, Copenhagen, 4 April – 13 April. ICES CM 2006/ACFM: 23. 254 pp.

ICES. 2007. Report of the Working Group on North Atlantic Salmon. ICES Headquarters, Copenhagen, 11–20 April. ICES CM 2007/ACFM: 13. 253 pp.

ICES. 2008. Report of the Working Group on North Atlantic Salmon. Galway, Ireland 1–10 April. ICES CM 2008/ACOM: 18. 235 pp.

ICES. 2009. Report of the Working Group on North Atlantic Salmon. ICES Headquarters, Copenhagen, 30 March–8 April 2009. ICES CM 2009/ACFM: 06. 283 pp.

ICES. 2012. Report of the Working Group on North Atlantic Salmon (WGNAS), 26 March–4 April 2012, Copenhagen, Denmark. ICES CM 2012/ACOM: 09. 322 pp.

ICES. 2015. Report of the Working Group on North Atlantic Salmon (WGNAS), 17–26 March, Moncton, Canada. ICES CM 2015/ACOM:09. 462 pp.

ICES. 2016. Report of the Working Group on North Atlantic Salmon (WGNAS), 30 March–8 April 2016, Copenhagen, Denmark. ICES CM 2016/ACOM:10. 363 pp.

ICES. 2018. Report of the Working Group on North Atlantic Salmon (WGNAS), 4–13 April 2018, Woods Hole, MA, USA. ICES CM 2018/ACOM:21. 386 pp.

ICES. 2021a. Workshop for Salmon Life Cycle Modelling (WKSalModel). ICES Scientific Reports. 3:24. 20 pp.
https://doi.org/10.17895/ices.pub.7921

ICES. 2021b. Working Group on North Atlantic Salmon (WGNAS). ICES Scientific Reports. 3:29. 407 pp.
https://doi.org/10.17895/ices.pub.7923

Jensen, J. M. 1990. Atlantic salmon at Greenland. Fisheries Research, 10: 29–52.

Massiot-Granier, F., Prévost, E., Chaput, G., Potter, T., Smith, G., White, J., Mäntyniemi, S., and Rivot, E. 2014. Embedding stock assessment within an integrated hierarchical Bayesian life cycle modelling framework: an application to Atlantic salmon in the Northeast Atlantic. ICES Journal of Marine Science, 71: 1653–1670.

Michielsens, C.G.J., McAllister, M.K., Kuikka, S., Mäntiniemi, S., Romakkaniemi, A., Pakinen, T., Karlsson, L., and Uusitalo, L. 2008. Combining multiple Bayesian data analyses in a sequential framework for quantitative fisheries stock assessment. Can. J. Fish. Aquat. Sci. 65: 962–974.

Olmos, M., Massiot-Granier, F., Prévost, E., Chaput, G., Bradbury, I. R., Nevoux, M., and Rivot, E. 2019. Evidence for spatial coherence in time trends of marine life history traits of Atlantic salmon in the North Atlantic. Fish and Fisheries, 20(2), 322–342.

Paloheimo, J. E., and Elson, P. F. 1974. Reduction of Atlantic Salmon (*Salmo salar*) Catches in Canada Attributed to the Greenland Fishery. Journal of the Fisheries Research Board of Canada, 31: 1467–1480.

Potter, E.C.E., Crozier, W.W., Schön, P-J., Nicholson, M.D., Maxwell, D. L., Prévost, E., Erkinaro, J., et al. 2004. Estimating and forecasting pre-fishery abundance of Atlantic salmon (*Salmo salar* L.) in the Northeast Atlantic for the management of mixed-stock fisheries. ICES Journal of Marine Science, 61: 1359–1369.

Prévost, E., Crozier, W.W. and Schön, P.-J. 2005. Static versus dynamic model for forecasting salmon pre-fishery abundance of the River Bush: a Bayesian comparison. Fisheries Research, 73: 111–
## 4.1.1 Annual time-series data

For the majority of stock-units the annual data include reported catch numbers by sea-age, together with estimates of unreported catch and exploitation rates by sea age each with associated uncertainty. For these stock-units the number of returns is then derived by raising the catches (after accounting for unreporting) by the exploitation rate for each age class.

For stock-units where alternative derivations of return estimates are more appropriate, different data are provided:

* For UK (Scotland), returns are derived nationally and provided directly as inputs to the RR model.

* From 2021 onwards, UK (England) returns are modelled from rod catch and release numbers instead of (total) reported catch.

* From 2000 onwards, UK (Northern Ireland – DAERA) returns are derived from catches and (scaled) counts from the rivers Bush and Bann.

* For Russia, annual time series for all stock-units were not updated with data for the years 2021 and 2022. ICES agreed an approach for the 2023 assessment to account for this deficiency by constructing catch estimates using alternative data sources (ICES, 2023). Additionally, an adjustment is made to the returns estimates to account for the additional uncertainty in the catches. Alternative approaches for accounting for this deficiency were discussed by WKBSalmon but were ultimately rejected in favour of the established method used by the ICES Working Group on North Atlantic Salmon (WGNAS) in 2023.

The N-NEAC forecast time series runs comprehensively from 1983 to 2022 (Table 4.1). While data for many regions are available from 1971, Norwegian data begin in 1983 and with six smolt ages, plus a two year sea-age, giving a first reporting year of 1991. For the S-NEAC stock-units (Table 4.1) time series run from 1971 to present. With the oldest smolt age being five years, plus two year sea-ages, the first reporting year is 1978. Further details of the Run-Reconstruction model and its inputs are provided in the Stock Annex.

<table><caption>Table 4.1. Time series ranges of available data for Atlantic salmon by stock unit for the Northern European (N-NEAC) and Southern European (S-NEAC) complexes.</caption><thead><tr><th>Continental Stock Complex</th><th>Region</th><th>From</th><th>To</th></tr></thead><tbody><tr><td rowspan="10">Northern Europe (N-NEAC)</td><td>Finland</td><td>1971</td><td>Present</td></tr><tr><td>Iceland North-east</td><td>1971</td><td>Present</td></tr><tr><td>Norway - North</td><td>1983</td><td>Present</td></tr><tr><td>Norway - Southeast</td><td>1983</td><td>Present</td></tr><tr><td>Norway Mid</td><td>1983</td><td>Present</td></tr><tr><td>Norway - Southwest</td><td>1983</td><td>Present</td></tr><tr><td>Russia - Archangel -Karelia</td><td>1971</td><td>Present</td></tr><tr><td>Russia - Kola Barent</td><td>1971</td><td>Present</td></tr><tr><td>Russia - Kola-White</td><td>1971</td><td>Present</td></tr><tr><td>Russia - Pechora River</td><td>1971</td><td>Present</td></tr></tbody></table>
122.

Rago, P. J. 2001. Index measures and stock assessment in Atlantic salmon. In Stock, recruitment and reference points: assessment and management of Atlantic salmon. pp. 137-176. Ed. by E. Prévost and G. Chaput. INRA Editions, Paris.

Rago, P.J., Reddin, D.G., Porter, T.R., Meerburg, D.J., Friedland, K.D., and Potter, E.C.E. 1993. A continental run reconstruction model for the non-maturing component of North American Atlantic salmon: analysis of fisheries in Greenland and Newfoundland-Labrador, 1974-1991. ICES C.M. 1993/M:25. 33 p.

Reddin, D.G., and Friedland, K.D. 1999. A history of identification to continent of origin of Atlantic salmon (*Salmo salar* L.) at west Greenland. Fisheries Research (Amsterdam), 43: 221-235.

Reddin, D.G., and Shearer, W.M. 1987. Sea-surface temperature and distribution of Atlantic salmon in the Northwest Atlantic Ocean. American Fisheries Society Symposium on Common Strategies in Anadromous/Catadromous Fishes, 1: 262-275.

Reddin, D. G., Hansen, L. P., Bakkestuen, V., Russell, I., White, J., Potter, E. C. E., Dempson, J. B., et al. 2012. Distribution and biological characteristics of Atlantic salmon (*Salmo salar*) at Greenland based on the analysis of historical tag recoveries. ICES Journal of Marine Science 69: 1589-1597.

Saunders, R. L., Kerswill, C. J., and Elson, P. F. 1965. Canadian Atlantic salmon recaptured near Greenland. Journal of the Fisheries Research Board of Canada, 22: 625-629.
<table><tr><td></td><td>Sweden</td><td>1971</td><td>Present</td></tr><tr><td rowspan="10">Southern Europe (S-NEAC)</td><td>England & Wales</td><td>1971</td><td>Present</td></tr><tr><td>France</td><td>1971</td><td>Present</td></tr><tr><td>Iceland South-west</td><td>1971</td><td>Present</td></tr><tr><td>Ireland</td><td>1971</td><td>Present</td></tr><tr><td>Northern Ireland - DAERA*</td><td>1971</td><td>Present</td></tr><tr><td>Northern Ireland - Foyle</td><td>1971</td><td>Present</td></tr><tr><td>Scotland - East</td><td>1971</td><td>Present</td></tr><tr><td>Scotland - West</td><td>1971</td><td>Present</td></tr></table>

## 4.1.2 Biological characteristics

In addition to time series of catches, exploitation rates and counts of fish, a set of biological characteristics are required as input to the lifecycle model. For most stock-units, fixed values are used. The exceptions are UK (England & Wales) and UK (Scotland), which provide time-series of fecundity (number of eggs per female) and proportion of females.

<table><caption>Table 4.2. Biological characteristics and average annual number of spawners for each stock unit. Fecundity is the expected number of eggs produced per female. Return month is the mid-month of return (since Jan. 1). Sex ratio is proportion of females. Spawners are given in number of fish and are included because they are used to convert between CLs in terms of eggs and fish and to split total CL of eggs into a 1SW and a MSW component (Table 4.3). Biological characteristics are the averages for the last 10 years (when provided as time-series).</caption><thead><tr><th>Stock unit</th><th>Return month 1SW</th><th>Return month MSW</th><th>Sex ratio 1SW</th><th>Sex ratio MSW</th><th>Fecundity 1SW</th><th>Fecundity MSW</th><th>Spawners 1SW</th><th>Spawners MSW</th></tr></thead><tbody><tr><td colspan="9">S-NEAC:</td></tr><tr><td>France</td><td>8.5</td><td>8.5</td><td>0.450</td><td>0.800</td><td>3 485</td><td>5 569</td><td>11 922</td><td>5 168</td></tr><tr><td>UK(E & W)</td><td>8.0</td><td>6.0</td><td>0.458</td><td>0.702</td><td>4 080</td><td>7 043</td><td>35 657</td><td>90 301</td></tr><tr><td>Ireland</td><td>8.0</td><td>5.0</td><td>0.600</td><td>0.850</td><td>3 400</td><td>7 000</td><td>168 899</td><td>18 405</td></tr><tr><td>UK(N. Ireland) FO</td><td>6.5</td><td>5.0</td><td>0.570</td><td>0.600</td><td>3 459</td><td>6 781</td><td>21 558</td><td>2 336</td></tr><tr><td>UK(N. Ireland) FB</td><td>7.0</td><td>5.5</td><td>0.570</td><td>0.600</td><td>3 459</td><td>6 781</td><td>13 953</td><td>1 950</td></tr><tr><td>UK(Scotland) EA</td><td>8.0</td><td>5.0</td><td>0.495</td><td>0.714</td><td>3 274</td><td>6 177</td><td>168 936</td><td>172 934</td></tr><tr><td>UK(Scotland) WE</td><td>8.0</td><td>7.0</td><td>0.495</td><td>0.714</td><td>3 282</td><td>6 179</td><td>35 337</td><td>12 870</td></tr><tr><td>Iceland SW</td><td>7.0</td><td>6.0</td><td>0.420</td><td>0.570</td><td>5 954</td><td>10 787</td><td>21 118</td><td>2 765</td></tr></tbody></table>

<footnote>* DAERA (Department of Agriculture, Environment and Rural Affairs) region</footnote>
TABLES

<table><caption>Table 1. Progression of North American stock complex level models for PFA used by ICES.</caption><thead><tr><th>Model</th><th>Explanatory variables</th></tr></thead><tbody><tr><td>PFA<sub>y</sub> = α + β Hab<sub>y</sub> + ε; ε ~ N(0, σ<sub>ε</sub><sup>2</sup>)</td><td>- Habitat index (March) (ICES 1994)<br>- Habitat index (sum of indices of January to March) (ICES 1995, 1996)</td></tr><tr><td>PFA<sub>y</sub> = α + β Hab<sub>y</sub> + γ LS<sub>y</sub> + ε; ε ~ N(0, σ<sub>ε</sub><sup>2</sup>)</td><td>- Habitat index (February)<br>- Lagged spawners (sum of Labrador, Newfoundland, Quebec, Scotia-Fundy, excluding Gulf and USA) (ICES 1996, 1997, 1998, 1999, 2000)</td></tr><tr><td>PFA<sub>y</sub> = LS<sub>y</sub><sup>γ</sup> e<sup>α + β Hab<sub>y</sub> e<sup>ε</sup></sup>; ε ~ N(0, σ<sub>ε</sub><sup>2</sup>)<br>fitted as<br>ln(PFA<sub>y</sub>) = α + β Hab<sub>y</sub> + γ ln(LS<sub>y</sub>) + ε</td><td>- Habitat index (February)<br>- Lagged spawners (sum of Labrador, Newfoundland, Quebec, Scotia-Fundy, excluding Gulf and USA)<br>- Incorporated uncertainty in PFA and LS variables as derived random draws from inputs to derive PFA and LS<br>- ICES (2001, 2002)</td></tr><tr><td>PFA<sub>y</sub> = e<sup>α + β Ph<sub>i</sub></sup> LS<sub>y</sub><sup>γ</sup> e<sup>δ Hab<sub>y</sub> e<sup>ε</sup></sup>; ε ~ N(0, σ<sub>ε</sub><sup>2</sup>)<br>fitted as<br>ln(PFA<sub>y</sub>) = α + β Ph<sub>i</sub> + γ ln(LS<sub>y</sub>) + δ Hab<sub>y</sub> + ε<br>With Ph an indicator variable of a phase in productivity represented by two time periods over 1979 to 2001<br>Ph<sub>i</sub> = {0 for y = 1979 to 1988; 1989<br>1 for y = 1990 to 2001; 1989</td><td>- Habitat index (February) (not significant)<br>- Lagged spawners (sum of Newfoundland, Quebec, Gulf, Scotia-Fundy, USA, excluding Labrador)<br>- Phase shift with 1989 year considered transitional and alternatively placed in either the upper phase or lower phase periods.<br>- Incorporated uncertainty in PFA and LS variables as derived random draws from inputs to derive PFA and LS<br>- ICES (2003)</td></tr><tr><td>PFA<sub>y</sub> = e<sup>α + β Ph<sub>i</sub></sup> LS<sub>y</sub><sup>γ + δ Ph<sub>i</sub></sup> e<sup>ε</sup>; ε ~ N(0, σ<sub>ε</sub><sup>2</sup>)<br>fitted as<br>ln(PFA<sub>y</sub>) = α + β Ph<sub>i</sub> + (γ + δ Ph<sub>i</sub>) ln(LS<sub>y</sub>) + ε<br>Nested models including two without phase shifts and five models with phase shifts and with eight possible break year points (1986 to 1993) for each model.</td><td>- Lagged spawners (sum of Newfoundland, Quebec, Gulf, Scotia-Fundy, USA, excluding Labrador)<br>- Phase shift with eight candidate break years (1986 to 1993)<br>- Incorporated uncertainty in PFA and LS variables as derived random draws from inputs to derive PFA and LS.<br>- For each random data set, most parsimonious model was selected using Akaike's Information Criterion and the selected model was used to generate a value for the probability density for the forecast year of interest.<br>- ICES (2004, 2005, 2006, 2007, 2008, 2009)</td></tr><tr><td>PFA<sub>i,k</sub> = LogN(PFA<sub>i,k</sub>, σ.PFA<sup>2</sup>); PFA<sub>i,k</sub> = log(LS<sub>i,k</sub>) + a<sub>i,k</sub> + ε<sub>i,k</sub><br>a<sub>i+1,k</sub> = a<sub>i,k</sub> + η<sub>i,k</sub>; η<sub>i,k</sub> ~ MVN(0, Σ)</td><td>- Region disaggregated lagged spawners and 2SW returns<br>- Bayesian model<br>- ICES (2009, 2012, 2015, 2018, 2021)</td></tr></tbody></table>
<table><thead><tr><th colspan="9">N-NEAC:</th></tr></thead><tbody><tr><td>Iceland NE</td><td>7.0</td><td>6.0</td><td>0.330</td><td>0.630</td><td>5 982</td><td>11 666</td><td>9 529</td><td>3 734</td></tr><tr><td>Sweden</td><td>8.3</td><td>7.5</td><td>0.310</td><td>0.610</td><td>3 113</td><td>7 625</td><td>3 786</td><td>5 292</td></tr><tr><td>Norway SE</td><td>8.0</td><td>5.0</td><td>0.362</td><td>0.682</td><td>2 449</td><td>7 250</td><td>30 545</td><td>43 300</td></tr><tr><td>Norway SW</td><td>8.0</td><td>5.0</td><td>0.362</td><td>0.682</td><td>2 449</td><td>7 250</td><td>5 712</td><td>14 925</td></tr><tr><td>Norway MI</td><td>8.0</td><td>5.0</td><td>0.464</td><td>0.673</td><td>2 262</td><td>7 619</td><td>49 928</td><td>52 423</td></tr><tr><td>Norway NO</td><td>8.0</td><td>5.0</td><td>0.175</td><td>0.710</td><td>2 571</td><td>9 399</td><td>20 932</td><td>28 877</td></tr><tr><td>Finland</td><td>6.0</td><td>6.5</td><td>0.120</td><td>0.770</td><td>5 000</td><td>13 000</td><td>12 646</td><td>8 912</td></tr><tr><td>Russia AK</td><td>7.5</td><td>8.0</td><td>0.100</td><td>0.800</td><td>4 500</td><td>12 000</td><td>3 515</td><td>5 021</td></tr><tr><td>Russia KW</td><td>8.5</td><td>7.5</td><td>0.600</td><td>0.400</td><td>4 500</td><td>10 500</td><td>55 091</td><td>7 684</td></tr><tr><td>Russia KB</td><td>7.0</td><td>6.5</td><td>0.100</td><td>0.800</td><td>3 500</td><td>12 500</td><td>6 943</td><td>5 312</td></tr><tr><td>Russia RP</td><td>8.0</td><td>8.0</td><td>0.100</td><td>0.700</td><td>4 500</td><td>15 000</td><td>1 439</td><td>10 793</td></tr></tbody></table>

### 4.1.3 Updates to the NEAC data

The following data was updated for the benchmark. UK (England & Wales) updated proportion of females and eggs per female from static values to time series (1971 – present). France updated their static values of proportion of females and eggs per female. Sweden updated all their static values, which includes proportion of females, eggs per female, smolt age distribution and mid-months of returns.

### 4.1.4 Conservation Limits for NEAC

River-specific Conservation Limits (CLs) have been derived for salmon stocks in most countries in the NEAC area (France, Ireland, UK – England and Wales, UK – Northern Ireland, UK – Scotland, Finland, Norway and Sweden) and these are used in national assessments. In these cases, CL estimates for individual rivers are summed to provide estimates at the national level for these countries. For Ireland, national CLs are provided in numbers of 1SW and MSW spawners, while for the other aforementioned countries, CLs are provided in total number of eggs for each stock unit. During the benchmark, France, UK – England and Wales and Sweden have updated their CLs and biological characteristics.

River-specific CLs have also been derived for several rivers in Russia and Iceland, but these are not yet used in national assessments. An interim approach has been developed for countries that do not use river-specific CLs in their national assessment. This approach is based on the establishment of pseudo-stock-recruitment relationships for national salmon stocks; further details are provided in the Stock Annex (Annex 5).

The updated CLs in their various forms (number of eggs or fish) are presented in Table 4.3. To convert between CLs in number of fish and number of eggs for age group *x* (1SW or MSW) the following relationship has been used:

$$CL_{\text{eggs}}(x) = CL_{\text{fish}}(x) \times \text{SexRatio}(x) \times \text{Fecundity}(x),$$
<table><caption>Table 2. Comparison of the structure and assumptions of the North American stock complex level model used by ICES to 2010 and the region-disaggregated model used since 2012.</caption><thead><tr><th>Feature</th><th>ICES North American complex model</th><th>Region-disaggregated model</th></tr></thead><tbody><tr><td>Input variables</td><td>Lagged spawners and PFA are generated from run-reconstruction and treated as observations, at the scale of NAC<br>PFA<sub>y</sub>|LS<sub>y</sub>, α, β, Ph<sub>i</sub>, σ</td><td>Distributions of lagged spawners and returns of 2SW salmon to regions are generated from run-reconstruction and treated as pseudo-observations in the model.<br>Ret2sw<sub>k,y+1</sub>|LS<sub>k,y</sub>, α<sub>k,y</sub>, WG1nm<sub>k,y</sub>, NL1nm<sub>k,y</sub>, NL2<sub>k,y+1</sub>, SPM2<sub>k,y+1</sub>, σ<sub>k</sub>, n<sub>k,y</sub></td></tr><tr><td>Spatial scale</td><td>Aggregated at the scale of North America</td><td>By six regions in North America</td></tr><tr><td>PFA period</td><td>August 1 of the second summer at sea for 1SW non-maturing salmon</td><td></td></tr><tr><td>Model dynamic</td><td>Incorporates possibility of two phases of productivity between lagged spawners and PFA. Recruitment rate parameter is an aggregate estimate of the productivity for NAC that can take one of two levels.</td><td>Random walk that models region specific recruitment rates in year i+1 as a function of region specific recruitment rate in year i, variance-covariance structure on recruitment rate</td></tr><tr><td>Consideration of uncertainty</td><td>Uncertainty in LS and PFA are incorporated by generating multiple data sets of LS and PFA using Monte Carlo simulations, used for selecting the parsimonious model for each simulation and generating a predicted PFA value for each simulated data set and model fit.</td><td>Uncertainty in lagged spawners and returns of 2SW salmon to regions are introduced as priors and can be updated. Posterior distributions of PFA and returns to regions are inferred from the model fitting.</td></tr><tr><td>Forecast capacity</td><td>Forecasts are based on lagged spawner values available for three years beyond the last observed 2SW return year and an estimate of the likelihood of being in the high phase or the low phase of productivity. Forecast values take one of two levels of recruitment rate.</td><td>Same forecast capacity as Working Group model excluding the need to estimate the probability of being in a high or low phase. Forecasts are based on estimated lagged spawners and the recruitment rate from the last observed year with variance from the entire time series.</td></tr><tr><td>Risk analysis of catch options</td><td>Assume characteristics of the catches will be similar to the range of values observed during previous five years. Catch options scenarios are explored.</td><td></td></tr></tbody></table>
where SexRatio(x) is the proportion female for age group x and Fecundity(x) is the average number of eggs per female for age group x.

To split the total CL in number of eggs (CL<sub>total</sub>) into the sea-age groups:

$$CL_{\text{eggs}}(x) = CL_{\text{total}} \frac{\text{Eggs}(x)}{\sum_{x} \text{Eggs}(x)}$$

where Eggs(x) is the average annual number of eggs produced by age group x in the last 10 years given by:

$$\text{Eggs}(x) = \text{Spawners}(x) \times \text{SexRatio}(x) \times \text{Fecundity}(x),$$

where Spawners(x) is the average number of annual spawners in the last 10 years. The biological characteristics used for these translations are given in Table 4.2. CL estimates for all individual stock-units can be summed to provide estimates at the country level and for the Northern and Southern NEAC stock complexes. Note that for UK – England and Wales, CL<sub>total</sub> was split into its age components nationally and directly provided to the working group and Ireland provided their CLs in numbers of 1SW and MSW fish. For all other stock-units, the CLs are provided as CL<sub>total</sub>.

These data are also used to estimate the Spawner Escapement Reserves (SERs; the CL increased to take account of natural mortality between the recruitment date of 1st January in the first sea winter and return to home waters).

$$\text{SER}(x) = CL_{\text{fish}}(x) \times e^{m \times t(x)},$$

where e denotes Euler's number, m = 0.03 is monthly marine mortality and t(x) the number of months between Jan. 1 of the first winter at sea and returns to rivers for sea-age x. SERs are estimated for maturing (1SW) and non-maturing (MSW) salmon for each stock unit (Table 4.3).

<table><caption>Table 4.3. Conservation limits for each stock unit in numbers of eggs and fish and the spawning escapement reserve (SER) in number of maturing (mat.) and non-maturing (non-mat.) 1SW fish.</caption><thead><tr><th>Stock unit</th><th>CL eggs total</th><th>CL eggs 1SW</th><th>CL eggs MSW</th><th>CL fish 1SW</th><th>CL fish MSW</th><th>SER mat.</th><th>SER non-mat.</th></tr></thead><tbody><tr><td colspan="8"><strong>S-NEAC:</strong></td></tr><tr><td>France</td><td>77 676 434</td><td>34 809 471</td><td>42 866 963</td><td>22 196</td><td>9 622</td><td>28 644</td><td>17 796</td></tr><tr><td>UK(E & W)</td><td>262 754 562</td><td>104 570 366</td><td>158 184 196</td><td>55 961</td><td>31 994</td><td>71 140</td><td>54 871</td></tr><tr><td>Ireland</td><td>710 711 690</td><td>431 400 840</td><td>279 310 850</td><td>211 471</td><td>46 943</td><td>268 832</td><td>78 174</td></tr><tr><td>UK(N. Ireland) FO</td><td>665 00 000</td><td>54 347 548</td><td>12 152 452</td><td>27 565</td><td>2 987</td><td>33 500</td><td>4 974</td></tr><tr><td>UK(N. Ireland) FB</td><td>273 00 000</td><td>21 189 166</td><td>6 110 834</td><td>10 747</td><td>1 502</td><td>13 258</td><td>2 539</td></tr><tr><td>UK(Scotland) EA</td><td>426 323 670</td><td>112 611 215</td><td>313 712 455</td><td>69 486</td><td>71 131</td><td>88 334</td><td>118 454</td></tr><tr><td>UK(Scotland) WE</td><td>13 4749 652</td><td>67 745 481</td><td>67 004 171</td><td>41 700</td><td>15 187</td><td>53 011</td><td>26 855</td></tr><tr><td>Iceland SW</td><td>51 606 484</td><td>39 038 779</td><td>12 567 705</td><td>15 611</td><td>2 044</td><td>19 259</td><td>3 508</td></tr><tr><td colspan="8"><strong>N-NEAC:</strong></td></tr><tr><td>Iceland NE</td><td>23 473 523</td><td>9 546 304</td><td>13 927 219</td><td>4 836</td><td>1 895</td><td>5 966</td><td>3 252</td></tr></tbody></table>
<table><caption>Table 3. Non-Canadian marine fisheries input data for the inference model.</caption><thead><tr><th>Year of fishery</th><th>West Greenland Reported Harvest (t)</th><th>West Greenland Unreported Harvest Estimate (t)</th><th>Mean weight (kg) in the fishery</th><th>Number of samples of NAC origin fish (DNA)</th><th>Number of samples of NEAC origin fish (DNA)</th><th>Min. prop. NAC from Scale Discrimination</th><th>Max. prop. NAC from Scale Discrimination</th><th>Prop. of NAC fish 1SW nonmat</th><th>St.Pierre & Miquelon large salmon harvest (number)</th></tr></thead><tbody><tr><td>1978</td><td>984</td><td>0</td><td>3.35</td><td>0</td><td>0</td><td>0.47</td><td>0.57</td><td>0.945</td><td>0</td></tr><tr><td>1979</td><td>1395</td><td>0</td><td>3.34</td><td>0</td><td>0</td><td>0.48</td><td>0.52</td><td>0.945</td><td>0</td></tr><tr><td>1980</td><td>1194</td><td>0</td><td>3.22</td><td>0</td><td>0</td><td>0.45</td><td>0.51</td><td>0.945</td><td>0</td></tr><tr><td>1981</td><td>1264</td><td>0</td><td>3.17</td><td>0</td><td>0</td><td>0.58</td><td>0.61</td><td>0.945</td><td>0</td></tr><tr><td>1982</td><td>1077</td><td>0</td><td>3.11</td><td>0</td><td>0</td><td>0.6</td><td>0.64</td><td>0.945</td><td>0</td></tr><tr><td>1983</td><td>310</td><td>0</td><td>3.1</td><td>0</td><td>0</td><td>0.38</td><td>0.41</td><td>0.945</td><td>348</td></tr><tr><td>1984</td><td>297</td><td>0</td><td>3.11</td><td>0</td><td>0</td><td>0.47</td><td>0.53</td><td>0.945</td><td>348</td></tr><tr><td>1985</td><td>864</td><td>0</td><td>2.87</td><td>0</td><td>0</td><td>0.46</td><td>0.53</td><td>0.925</td><td>348</td></tr><tr><td>1986</td><td>960</td><td>0</td><td>3.03</td><td>0</td><td>0</td><td>0.48</td><td>0.66</td><td>0.951</td><td>290</td></tr><tr><td>1987</td><td>966</td><td>0</td><td>3.16</td><td>0</td><td>0</td><td>0.54</td><td>0.63</td><td>0.963</td><td>232</td></tr><tr><td>1988</td><td>893</td><td>0</td><td>3.18</td><td>0</td><td>0</td><td>0.38</td><td>0.49</td><td>0.967</td><td>232</td></tr><tr><td>1989</td><td>337</td><td>0</td><td>2.87</td><td>0</td><td>0</td><td>0.52</td><td>0.6</td><td>0.923</td><td>232</td></tr><tr><td>1990</td><td>274</td><td>0</td><td>2.69</td><td>0</td><td>0</td><td>0.7</td><td>0.79</td><td>0.957</td><td>218</td></tr><tr><td>1991</td><td>472</td><td>0</td><td>2.65</td><td>0</td><td>0</td><td>0.61</td><td>0.69</td><td>0.956</td><td>135</td></tr><tr><td>1992</td><td>237</td><td>0</td><td>2.81</td><td>0</td><td>0</td><td>0.5</td><td>0.57</td><td>0.919</td><td>269</td></tr><tr><td>1993</td><td>0</td><td>12</td><td>2.73</td><td>0</td><td>0</td><td>0.5</td><td>0.76</td><td>0.946</td><td>342</td></tr><tr><td>1994</td><td>0</td><td>12</td><td>2.73</td><td>0</td><td>0</td><td>0.5</td><td>0.76</td><td>0.946</td><td>398</td></tr><tr><td>1995</td><td>83</td><td>20</td><td>2.56</td><td>0</td><td>0</td><td>0.65</td><td>0.72</td><td>0.968</td><td>97</td></tr><tr><td>1996</td><td>92</td><td>20</td><td>2.88</td><td>0</td><td>0</td><td>0.71</td><td>0.76</td><td>0.941</td><td>182</td></tr><tr><td>1997</td><td>58</td><td>5</td><td>2.71</td><td>0</td><td>0</td><td>0.75</td><td>0.84</td><td>0.982</td><td>173</td></tr><tr><td>1998</td><td>11</td><td>11</td><td>2.78</td><td>0</td><td>0</td><td>0.73</td><td>0.84</td><td>0.968</td><td>268</td></tr><tr><td>1999</td><td>19</td><td>12.5</td><td>3.08</td><td>0</td><td>0</td><td>0.84</td><td>0.97</td><td>0.968</td><td>270</td></tr><tr><td>2000</td><td>21</td><td>10</td><td>2.57</td><td>344</td><td>146</td><td>0</td><td>0</td><td>0.974</td><td>263</td></tr><tr><td>2001</td><td>43</td><td>10</td><td>3.00</td><td>1</td><td>1</td><td>0.67</td><td>0.71</td><td>0.982</td><td>250</td></tr><tr><td>2002</td><td>9.8</td><td>10</td><td>2.90</td><td>338</td><td>163</td><td>0</td><td>0</td><td>0.973</td><td>227</td></tr><tr><td>2003</td><td>12.3</td><td>10</td><td>3.04</td><td>1212</td><td>567</td><td>0</td><td>0</td><td>0.967</td><td>348</td></tr><tr><td>2004</td><td>17.2</td><td>10</td><td>3.18</td><td>1192</td><td>447</td><td>0</td><td>0</td><td>0.970</td><td>196</td></tr><tr><td>2005</td><td>17.3</td><td>10</td><td>3.31</td><td>585</td><td>182</td><td>0</td><td>0</td><td>0.924</td><td>351</td></tr><tr><td>2006</td><td>23.0</td><td>10</td><td>3.24</td><td>857</td><td>326</td><td>0</td><td>0</td><td>0.930</td><td>469</td></tr><tr><td>2007</td><td>24.8</td><td>10</td><td>2.98</td><td>917</td><td>206</td><td>0</td><td>0</td><td>0.965</td><td>218</td></tr><tr><td>2008</td><td>28.6</td><td>10</td><td>3.08</td><td>1593</td><td>260</td><td>0</td><td>0</td><td>0.974</td><td>442</td></tr></tbody></table>
<table><tr><td>Sweden</td><td>14 085 976</td><td>1 820 594</td><td>12 265 382</td><td>1 887</td><td>2 637</td><td>2 420</td><td>4 733</td></tr><tr><td>Norway SE</td><td>85 098 198</td><td>9 554 841</td><td>75 543 357</td><td>10 778</td><td>15 278</td><td>13 701</td><td>25 442</td></tr><tr><td>Norway SW</td><td>35 828 123</td><td>2 300 646</td><td>33 527 477</td><td>2 595</td><td>6 781</td><td>3 299</td><td>11 292</td></tr><tr><td>Norway MI</td><td>230 635 712</td><td>37 626 794</td><td>193 008 918</td><td>35 850</td><td>37 641</td><td>45 574</td><td>62 682</td></tr><tr><td>Norway NO</td><td>92 459 310</td><td>4 308 112</td><td>88 151 198</td><td>9 575</td><td>13 210</td><td>12 172</td><td>21 997</td></tr><tr><td>Finland</td><td>104 274 286</td><td>8 173 744</td><td>96 100 542</td><td>13 623</td><td>9 600</td><td>16 310</td><td>16 723</td></tr><tr><td>Russia AK</td><td>59 969 694</td><td>1 905 397</td><td>58 064 297</td><td>4 234</td><td>6 048</td><td>5 303</td><td>11 020</td></tr><tr><td>Russia KW</td><td>158 641 870</td><td>130 358 477</td><td>28 283 393</td><td>48 281</td><td>6 734</td><td>62 305</td><td>12 087</td></tr><tr><td>Russia KB</td><td>81 292 441</td><td>3 556 157</td><td>77 736 284</td><td>10 160</td><td>7 774</td><td>12 535</td><td>13 542</td></tr><tr><td>Russia RP</td><td>92 985 618</td><td>528 303</td><td>92 457 315</td><td>1 174</td><td>8 805</td><td>1 492</td><td>16 044</td></tr></table>

## 4.2 North American Commission Data

In the Northwest Atlantic anadromous Atlantic salmon (*Salmo salar* L.) ranges from northeastern USA (State of Connecticut; 41.29°N, 72.34°W) to northern Canada (Ungava Bay; 58.78°N 70.25°W). There are 900 anadromous Atlantic Salmon rivers in the northwest Atlantic area, 855 rivers in eastern Canada and 45 anadromous Atlantic Salmon rivers in the USA (NASCO rivers database).

### 4.2.1 Stock units for North American Commission Area (NAC)

There are no changes in the stock-units for NAC from those originally defined for the ICES PFA forecast and modelling approach.

The ICES run reconstruction, PFA forecast model and the Life Cycle Model aggregate individual river abundances into six stock-units for North America: the USA and the five main provincial / jurisdictional regions in eastern Canada comprising Labrador, Newfoundland, Quebec, Gulf and Scotia-Fundy (Figure 4.1). The stock-units reflect the jurisdictional boundaries of the Fisheries and Oceans Canada, the province of Quebec and the USA. For Canada, the stock-units are aggregates of management areas, termed Salmon Fishing Area (SFA) and Quebec management zones (Q) (Figure 4.1; Table 4.4). The stock-units correspond in large part to the geographic structure of sea-age and life history characteristics of anadromous salmon in eastern Canada (Porter *et al.*, 1986; O'Connell *et al.*, 2006). The compilations of data on stocks within each jurisdiction are of importance to regional / national managers.

Recently, Bradbury *et al.* (2021; and earlier work) reported on the identification of genetically discrete reporting groups of Atlantic salmon. The latest iteration reported in Bradbury *et al.* (2021) and used by ICES (2023) uses a panel of 96 Single Nucleotide Polymorphism (SNPs) to jointly distinguish 30 stock-units in the North Atlantic, 21 for NAC (including a NAC aquaculture group) and 10 for NEAC.

Five of the six NAC stock-units used to date by ICES each encompass several genetic reporting groups; the exception being USA which has a single reporting group (Table 4.4). With few exceptions, each individual genetic reporting group is contained within a single stock unit. Exceptions to this occur along boundaries of the stock-units, particularly between the Quebec
<table><thead><tr><th>Year of fishery</th><th>West Greenland Reported Harvest (t)</th><th>West Greenland Unreported Harvest Estimate (t)</th><th>Mean weight (kg) in the fishery</th><th>Number of samples of NAC origin fish (DNA)</th><th>Number of samples of NEAC origin fish (DNA)</th><th>Min. prop. NAC from Scale Discrimination</th><th>Max. prop. NAC from Scale Discrimination</th><th>Prop. of NAC fish 1SW nonmat</th><th>St.Pierre & Miquelon large salmon harvest (number)</th></tr></thead><tbody><tr><td>2009</td><td>28.0</td><td>10</td><td>3.50</td><td>1484</td><td>138</td><td>0</td><td>0</td><td>0.934</td><td>408</td></tr><tr><td>2010</td><td>43.1</td><td>10</td><td>3.42</td><td>991</td><td>249</td><td>0</td><td>0</td><td>0.982</td><td>470</td></tr><tr><td>2011</td><td>27.4</td><td>10</td><td>3.40</td><td>888</td><td>72</td><td>0</td><td>0</td><td>0.939</td><td>1031</td></tr><tr><td>2012</td><td>34.5</td><td>10</td><td>3.44</td><td>1121</td><td>252</td><td>0</td><td>0</td><td>0.932</td><td>156</td></tr><tr><td>2013</td><td>47.7</td><td>10</td><td>3.35</td><td>938</td><td>211</td><td>0</td><td>0</td><td>0.949</td><td>1272</td></tr><tr><td>2014</td><td>70.4</td><td>10</td><td>3.32</td><td>660</td><td>260</td><td>0</td><td>0</td><td>0.913</td><td>611</td></tr><tr><td>2015</td><td>60.9</td><td>10</td><td>3.37</td><td>1337</td><td>337</td><td>0</td><td>0</td><td>0.970</td><td>410</td></tr><tr><td>2016</td><td>30.2</td><td>10</td><td>3.18</td><td>864</td><td>438</td><td>0</td><td>0</td><td>0.935</td><td>286</td></tr><tr><td>2017</td><td>28.0</td><td>10</td><td>3.49</td><td>734</td><td>252</td><td>0</td><td>0</td><td>0.925</td><td>78</td></tr><tr><td>2018</td><td>39.0</td><td>10</td><td>2.97</td><td>814</td><td>165</td><td>0</td><td>0</td><td>0.974</td><td>214</td></tr><tr><td>2019</td><td>28.3</td><td>10</td><td>2.96</td><td>766</td><td>305</td><td>0</td><td>0</td><td>0.959</td><td>182</td></tr><tr><td>2020</td><td>30.9</td><td>10</td><td>3.19</td><td>60</td><td>20</td><td>0</td><td>0</td><td>0.953</td><td>214</td></tr></tbody></table>
and Gulf stock-units, the Gulf and Scotia-Fundy stock-units and to a lesser extent between Quebec and Labrador stock-units (Table 4.4; Figure 4.1).

For several stock-units, it would be possible to reconstruct returns and spawners to the finer scale genetic reporting groups beginning in 1984 and from 1971 to present for the regional reporting groups of Newfoundland, Gulf, Scotia-Fundy and USA. The exceptions are:

* The Quebec estimates prior to 1984 are presently available only at the scale of the province.

* For Labrador, the reconstruction of returns and spawners from 1971 to 1998 is based on the commercial catches from the Labrador region, estimates of exploitation and assumptions on the proportion of the harvests of Labrador origin (see run reconstruction details). It would not be possible with the current run reconstruction data to assess the three Labrador reporting groups defined in Bradbury *et al.* (2021).

Additional data would be required to partition into the regional reporting groups the coastal commercial fishery harvests from Quebec and the Maritime provinces prior to 1984, rather than attributing the commercial harvests from the coastal area of a region to the stock unit or regional group. There is also no information with which to partition the harvests in the Newfoundland (1971 to 1991) and Labrador (1971 to 1997) commercial fisheries to either the ICES stock-units or the finer scale regional reporting groups. In the PFA forecast and catch advice model, it is assumed that the stock unit contributions of these fisheries correspond to the proportions of the returns to the stock-units (see commercial fisheries harvest attributions). These issues may be resolvable using genetics and historical scale samples and could be considered based on future needs of life cycle modelling and catch advice for NASCO.

<table><caption>Table 4.4. Reconciliation of ICES North American stock-units to management areas and genetic reporting groups based on microsatellites (Bradbury *et al.*, 2014) and on a 96 SNP baseline (Bradbury *et al.*, 2021; ICES, 2023).</caption><thead><tr><th rowspan="2">ICES stock unit</th><th rowspan="2">Management area</th><th colspan="2">ICES regional reporting group</th></tr><tr><th>Micro-satellites</th><th>SNP</th></tr></thead><tbody><tr><td>US</td><td>US</td><td>US</td><td>US</td></tr><tr><td rowspan="4">Scotia-Fundy</td><td>SFA 23</td><td>Gulf of St. Lawrence</td><td>Outer Bay of Fundy</td></tr><tr><td>SFA 22</td><td>Inner Bay of Fundy</td><td>Inner Bay of Fundy</td></tr><tr><td>SFA 21</td><td rowspan="2">Nova Scotia</td><td rowspan="2">Nova Scotia</td></tr><tr><td>SFA 20</td></tr><tr><td rowspan="6">Gulf</td><td>SFA 19</td><td rowspan="4">Gulf of St. Lawrence</td><td rowspan="4">Gulf of St. Lawrence</td></tr><tr><td>SFA 18</td></tr><tr><td>SFA 17</td></tr><tr><td>SFA 16</td></tr><tr><td>SFA 15</td><td></td></tr><tr><td rowspan="9">Quebec</td><td>Q1</td><td rowspan="3">Gaspe</td><td rowspan="3">Gaspe</td></tr><tr><td>Q2</td></tr><tr><td>Q3</td></tr><tr><td>Q5</td><td rowspan="3">Quebec</td><td rowspan="3">Quebec</td></tr><tr><td>Q6</td></tr><tr><td>Q7</td></tr><tr><td>Q8</td><td rowspan="2">Quebec / Labrador South</td><td rowspan="2">Quebec</td></tr><tr><td>Q9</td></tr></tbody></table>
<table><caption>Table 4. Canadian marine fisheries input data for the inference model to 2020.</caption><thead><tr><th>Year of fishery</th><th>Labrador Commercial Harvest of Large</th><th>Labrador Commercial Harvest of Small</th><th>Newfoundland Commercial Harvest of Large in SFA 3 to 7</th><th>Newfoundland Commercial Harvest of Small in SFA 3 to 7</th><th>Newfoundland Commercial Harvest of Large in SFA 8 to 14A</th><th>Labrador FSC Harvest Small</th><th>Labrador FSC Harvest Large</th></tr></thead><tbody><tr><td>1978</td><td>91473</td><td>33656</td><td>64073</td><td>68747</td><td>37653</td><td>0</td><td>0</td></tr><tr><td>1979</td><td>52238</td><td>45714</td><td>29936</td><td>140844</td><td>29122</td><td>0</td><td>0</td></tr><tr><td>1980</td><td>124955</td><td>103479</td><td>86941</td><td>186648</td><td>54307</td><td>0</td><td>0</td></tr><tr><td>1981</td><td>112334</td><td>114680</td><td>98672</td><td>174222</td><td>38663</td><td>0</td><td>0</td></tr><tr><td>1982</td><td>83243</td><td>79449</td><td>46076</td><td>143445</td><td>35055</td><td>0</td><td>0</td></tr><tr><td>1983</td><td>60212</td><td>49441</td><td>48218</td><td>116592</td><td>28215</td><td>0</td><td>0</td></tr><tr><td>1984</td><td>43202</td><td>25590</td><td>44540</td><td>98184</td><td>15135</td><td>0</td><td>0</td></tr><tr><td>1985</td><td>33995</td><td>47359</td><td>36975</td><td>131360</td><td>24383</td><td>0</td><td>0</td></tr><tr><td>1986</td><td>58565</td><td>71396</td><td>48996</td><td>151275</td><td>22036</td><td>0</td><td>0</td></tr><tr><td>1987</td><td>79170</td><td>89454</td><td>67072</td><td>192308</td><td>19241</td><td>0</td><td>0</td></tr><tr><td>1988</td><td>49598</td><td>83109</td><td>36449</td><td>115375</td><td>14763</td><td>0</td><td>0</td></tr><tr><td>1989</td><td>47743</td><td>56486</td><td>37576</td><td>116375</td><td>15577</td><td>0</td><td>0</td></tr><tr><td>1990</td><td>27487</td><td>33027</td><td>31847</td><td>71761</td><td>11639</td><td>0</td><td>0</td></tr><tr><td>1991</td><td>13465</td><td>26768</td><td>25792</td><td>62331</td><td>10259</td><td>0</td><td>0</td></tr><tr><td>1992</td><td>32341</td><td>24249</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>1993</td><td>17096</td><td>17074</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>1994</td><td>15377</td><td>8640</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>1995</td><td>11176</td><td>7980</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>1996</td><td>7272</td><td>7849</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>1997</td><td>6943</td><td>9753</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>1998</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>2988</td><td>2269</td></tr><tr><td>1999</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>2739</td><td>1084</td></tr><tr><td>2000</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>5323</td><td>1352</td></tr><tr><td>2001</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>4789</td><td>1721</td></tr><tr><td>2002</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>5806</td><td>1389</td></tr><tr><td>2003</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>6477</td><td>2175</td></tr><tr><td>2004</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>8385</td><td>3696</td></tr><tr><td>2005</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>10436</td><td>2817</td></tr><tr><td>2006</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>10377</td><td>3090</td></tr><tr><td>2007</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>9208</td><td>2652</td></tr><tr><td>2008</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>9834</td><td>3909</td></tr><tr><td>2009</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>7988</td><td>3344</td></tr></tbody></table>
<table><tbody><tr><td rowspan="4">Labrador</td><td>SFA 14B</td><td>Labrador South</td></tr><tr><td>SFA 2</td><td rowspan="2">Labrador Central</td><td>Central Labrador</td></tr><tr><td>SFA 1B</td><td>Northern Labrador</td></tr><tr><td>SFA 1A</td><td>Ungava / Northern Labrador</td><td>Ungava</td></tr><tr><td rowspan="2">Quebec</td><td>Q11</td><td rowspan="2">Anticosti</td><td>Anticosti</td></tr><tr><td>Q10</td><td></td></tr><tr><td rowspan="12">Newfoundland</td><td>SFA 14A</td><td>Northwest Newfoundland</td></tr><tr><td>SFA 3</td><td rowspan="4">Newfoundland</td><td>Newfoundland 1</td></tr><tr><td>SFA 4</td><td></td></tr><tr><td>SFA 5</td><td></td></tr><tr><td>SFA 6</td><td></td></tr><tr><td>SFA 7</td><td rowspan="3">Avalon</td><td>Avalon</td></tr><tr><td>SFA 8</td><td></td></tr><tr><td>SFA 9</td><td></td></tr><tr><td>SFA 10</td><td>Burin Peninsula</td></tr><tr><td>SFA 11</td><td rowspan="3">Newfoundland</td><td>Fortune Bay</td></tr><tr><td>SFA 12</td><td>Newfoundland 2</td></tr><tr><td>SFA 13</td><td>Southwest Newfoundland</td></tr></tbody></table>
<table><thead><tr><th>Year of fishery</th><th>Labrador<br>Commercial<br>Harvest of Large</th><th>Labrador<br>Commercial<br>Harvest of<br>Small</th><th>Newfoundland<br>Commercial Harvest<br>of Large in SFA 3 to<br>7</th><th>Newfoundland<br>Commercial Harvest<br>of Small in SFA 3 to<br>7</th><th>Newfoundland<br>Commercial Harvest<br>of Large in SFA 8 to<br>14A</th><th>Labrador FSC<br>Harvest Small</th><th>Labrador FSC<br>Harvest Large</th></tr></thead><tbody><tr><td>2010</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>9867</td><td>3725</td></tr><tr><td>2011</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>11138</td><td>4451</td></tr><tr><td>2012</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>9977</td><td>4228</td></tr><tr><td>2013</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>7185</td><td>6479</td></tr><tr><td>2014</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>8958</td><td>3994</td></tr><tr><td>2015</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>8923</td><td>6146</td></tr><tr><td>2016</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>7638</td><td>5598</td></tr><tr><td>2017</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>6868</td><td>6193</td></tr><tr><td>2018</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>8780</td><td>4078</td></tr><tr><td>2019</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>7061</td><td>5793</td></tr><tr><td>2020</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>7558</td><td>6155</td></tr></tbody></table>
<figure><img src="image_7.png" /><figcaption>Figure 4.1. A) Salmon Fishing Areas (SFA) and Quebec management zones (Q) for eastern Canada. B) Stock units for North American Atlantic Salmon used by ICES and the corresponding baseline samples of rivers and their attribution to genetic reporting groups based on SNPs (Bradbury *et al.*, 2021; ICES, 2023).</figcaption></figure>

### 4.2.2 Data inputs for the PFA forecast and LCM model

The run-reconstruction model developed by Rago *et al.* (1993) was originally intended to estimate the pre-fishery abundance (PFA) of non-maturing 1SW salmon of North American origin (beginning in 1971) for the purpose of providing forecasts of potential 2SW salmon abundance and advice for the West Greenland fishery. The focus on the non-maturing 1SW salmon component was because the West Greenland fishery exploits predominantly (>95%) 1SW non-maturing salmon (destined to return primarily as 2SW salmon). The other fish taken in the fishery represent 2SW and older non-maturing salmon and previous spawners (ICES 2023).

Subsequently, there was an increased interest in estimating returns, spawners and PFA for all sea-age groups (1SW maturing, 1SW non-maturing, 2SW) and the two reporting size groups (small salmon, large salmon). This allowed the presentation of stock status domestically and internationally and in the evolution of the models used by ICES to summarize stock status and provide catch advice for the West Greenland and potential Faroes fisheries.

The run-reconstruction concepts developed by Rago *et al.* (1993) were applied to these sea-age and size groups. ICES defined the two size groups as follows:

* Small salmon: in the recreational and subsistence fisheries refer to salmon less than 63 cm fork length. In historic commercial fisheries small salmon refer to fish less than 2.7 kg whole weight. The majority of the salmon in this size group are 1SW first time spawning salmon with a small proportion, depending upon geographic area, comprising other age groups including 2SW first time spawning salmon and repeat spawners. The small salmon category is used synonymously with 1SW (maturing) salmon.

* Large salmon: generally in recreational and subsistence fisheries are greater than or equal to 63 cm fork length. In historic commercial fisheries large salmon refer to fish greater than or equal to 2.7 kg whole weight. Salmon in this size category comprise a diverse sea-age and spawning history structure but in most geographic areas they are comprised of a high proportion of 2SW and 3SW (very small proportions of older first-time spawning age groups) first time spawners and varying proportions of repeat spawners. In some
<table><caption>Table 5. Correlation matrix (median, 2.5 to 97.5 percentile range) of the productivity parameter among regions.</caption><thead><tr><th></th><th>LAB</th><th>NF</th><th>QC</th><th>GF</th><th>SF</th></tr></thead><tbody><tr><th>NF</th><td>0.355<br>(-0.10 to 0.636)</td><td></td><td></td><td></td><td></td></tr><tr><th>QC</th><td>0.243<br>(-0.92 to 0.521)</td><td>0.176<br>(-0.155 to 0.477)</td><td></td><td></td><td></td></tr><tr><th>GF</th><td>0.170<br>(-0.203 to 0.496)</td><td>0.054<br>(-0.304 to 0.406)</td><td>0.344<br>(0.035 to 0.581)</td><td></td><td></td></tr><tr><th>SF</th><td>0.194<br>(-0.206 to 0.528)</td><td>0.188<br>(-0.208 to 0.532)</td><td>0.459<br>(0.165 to 0.677)</td><td>0.588<br>(0.247 to 0.756)</td><td></td></tr><tr><th>USA</th><td>0.215<br>(-0.153 to 0.529)</td><td>0.268<br>(-0.88 to 0.570)</td><td>0.473<br>(0.208 to 0.678)</td><td>0.400<br>(0.095 to 0.632)</td><td>0.536<br>(0.237 to 0.743)</td></tr></tbody></table>
areas of Newfoundland, the large salmon comprise a very high proportion of repeat spawners that first spawned as 1SW fish. In the Labrador commercial fisheries, the large salmon category was considered to include a proportion of 1SW non-maturing salmon, destined to have become 2SW salmon or older in the following year had they not been captured. These 1SW non-maturing salmon are included in a catch vector that is incorporated within the PFA and LCM models.

In contrast to the data inputs for the run reconstruction in the NEAC area, the inputs that are used to reconstruct returns and spawners for the six stock-units of NAC are provided as ranges of returns and spawners by jurisdictional experts, at sub-stock unit geographic scales. The returns in these assessment units were derived by applying a variety of methods to data available for individual river systems and management areas. These methods included counts of salmon at monitoring facilities, population estimates from mark-recapture studies and the application of angling and commercial catch statistics, angling exploitation rates and measurements of freshwater habitat to raise returns to assessment areas (Table 4.5; Stock Annex).

The run reconstruction of returns to the six stock-units of NAC represent stock unit abundances after the marine fisheries of Newfoundland, Labrador and Saint Pierre and Miquelon. Historically, the fisheries of Labrador (to 1997) and Newfoundland (to 1991) harvested salmon from all stock-units of eastern North America; the contemporary fishery of Saint Pierre and Miquelon (ongoing) harvests salmon from most regions of North America (ICES, 2023).

The time series of returns by size group and sea-age group for the six stock-units extend from 1970 (1971 for USA) to present. Descriptions of the input data by sub-stock unit used in the run reconstruction of returns and catches (spawners for the PFA models used by ICES) for the six stock-units of North America are summarized in Table 4.5 and summarized below. Details are provided in the NAC Stock Annex.

* USA: estimates of returns are provided for the stock unit as midpoint only for small salmon, large salmon and for 2SW salmon (subset of large salmon). These estimates of returns are derived from counts at fishways and from redd/spawner counts in smaller rivers. A narrow range of uncertainty (0.99 to 1.01 of midpoint) is added to give a minimum (min) to maximum (max) range for the stock unit. The time series extend from 1971 to present.

* Scotia-Fundy: return estimates are provided for two geographic areas (SFA 19-21, SFA 23). For SFA 19-21, returns to a monitored river are raised by ratio of recreational catches in the monitored river to catches in all SFA 19-21. For SFA 23, returns to the monitored river(s) are raised by habitat area of rivers in SFA 23. The SFA specific estimates of returns include the commercial harvests that occurred in the SFA. The time series extend from 1970 to present.

* Gulf: return estimates, with uncertainty range, are provided for 4 SFAs. The returns in each SFA are obtained from returns to SFA specific monitored rivers, raised by either ratios of recreational catches by SFA or by ratio of habitat area (SFA 16). The SFA specific estimates of returns include the commercial and Indigenous fisheries harvests that occurred in the SFA. The time series extend from 1970 to present.

* Quebec: return estimates to the stock unit are derived differently for two time periods. For 1970 to 1983, total returns to rivers, based on one of six categories of assessment, uncertainty are provided to which are added the commercial harvests and other losses outside the river returns. For 1984 to present, river-specific estimates of returns, with uncertainty ranges, are provided. An uncertainty range for each management zone (10 in total) is calculated as the sum of respective min to max ranges of rivers within each zone. Annual commercial harvests and other losses outside the river are added to the annual stock unit total range. The time series extend from 1970 to present.
FIGURES

<figure><img src="image_3.png" /><figcaption>Figure 1. The six regions in North America used to model the dynamics between 2SW lagged spawners and 2SW returns to rivers.</figcaption></figure>
* Newfoundland: Estimates of returns to rivers are provided for each of the 11 SFAS in Newfoundland (SFA 3 to 14A). Returns are estimated from reported/estimated recreational fishery harvests of small salmon, raised by annual exploitation rates of small salmon harvests derived from rivers with monitoring facilities. Large salmon returns are estimated from the ratios of large salmon to small salmon at monitoring facilities, applied to estimated returns of small salmon. A non-parametric bootstrap with replacement is used to derive a min to max exploitation rate range and ratios of large to small salmon with the 95% confidence interval range used as the minimum and maximum estimates of returns. The time series extend from 1970 to present. Commercial harvests in the Newfoundland fishery are excluded from the estimates of returns to the Newfoundland stock unit.

* Labrador: For 1970 to 1997, estimates of returns were derived from the commercial harvests of salmon in the Labrador fishery adjusted by the estimated exploitation rate of the Labrador commercial fishery and with assumed proportions of Labrador origin salmon in the fishery harvests. For 2002 to present, returns to rivers of Labrador are derived based on returns to 3 or 4 monitored rivers, raised by ratios of watershed areas of monitored rivers to all salmon rivers of Labrador. For 1997 to 2001, as the commercial fishery was eventually closed and in the build-up of the monitoring rivers, returns were estimated from recreational fishery catches and exploitation rates in the recreational fishery of the years 2002 to 2008. The time series extend from 1970 to present. Commercial harvests of Labrador origin salmon in the Labrador fishery are excluded from the estimates of returns to the Labrador stock unit. A review of the run-reconstruction coding to derive returns to rivers of Labrador for 1SW and MSW sea-age groups should be done to ensure the reconstructions are consistent for the entire time-series.

### 4.2.3 Differences in the run-reconstruction to derive the stock unit inputs for the PFA model and for the LCM

The ICES WGNAS report (see ICES 2023 for example) presents and uses annual estimates of returns and spawners for small salmon, large salmon and 2SW salmon to characterize the stock status. PFA abundance estimates from run reconstruction were also presented for the corresponding size / sea-age groups for the NAC area. Spawners for each stock unit were derived using the run reconstruction model and sub-stock unit inputs of spawners provided by jurisdictional experts, using similar approaches described for the returns (see Table 4.5). Spawners are returns minus all losses in fisheries and include losses due to mortality of inriver caught and released salmon in recreational fisheries.

The PFA forecast model used by ICES until 2021 used estimates of returns and lagged spawners of the 2SW salmon component for each of the six stock-units, lagged to the pre-fishery abundance year (PFA of August 1 of the second summer at sea). The 2SW returns and spawners are a component of the large returns and these were derived using the sea-age composition of one or more indicator stocks. Lagged spawners, defined as spawners that would contribute recruitment at the PFA stage based on the proportion of the river age expected in each stock unit, are derived within the run-reconstruction model based on stock unit inputs of the expected smolt age proportions for an egg deposition year (see biological characteristics Section 4.2.5).

The LCM model does not require inputs of lagged spawners or eggs. The spawners are estimated from the returns and harvests inputs for each stock unit and their attribution to the year of PFA abundance occurs within the model based on the proportion smolt age vector or annual matrix provided for each stock unit.
<figure><img src="image_4.png" /><figcaption>Figure 2. Summary of flow of data from run reconstruction to the NAC PFA inference and forecast model for 2SW returns.</figcaption></figure>
The LCM model does require an input of harvests by size / sea-age group for each stock unit, which was previously not required from the run reconstruction for the PFA model. For NAC, sub-stock unit inputs continue to be in terms of returns and spawners. From these, harvests (total losses in fisheries) are derived as the difference between returns and spawners; the run reconstruction code has been modified to do this calculation and point estimates of the harvests are derived as the difference of the medians of the MCMC distributions of returns and spawners.

For the USA stock unit, spawners may exceed returns in some years due to hatchery programs. An additional input to the LCM is a vector of stocked spawners that accounts for the contribution of captive-reared salmon released to the wild to spawn.

### 4.2.4 Changes to the LCM inputs from the previous version

To harmonize the LCM structure between the NAC and NEAC areas, it was decided to consider the two sea-age groups as 1SW and MSW, rather than 1SW and 2SW as was done previously for NAC. Based on extensive sampling across stock-units in NAC, the small salmon size category is considered equivalent to the 1SW sea-age component. The large salmon category, which would include 1SW (in very low proportions), 2SW, 3SW and older first time spawner ages as well as repeat spawning salmon, is considered equivalent to MSW salmon. Corresponding biological characteristics for the 1SW and MSW components were revised accordingly when warranted (see biological characteristics, Section 4.2.5).

<table><caption>Table 4.5. Summary of input data and derivation of uncertainties used in the run reconstruction of returns to the six stock-units of NAC.</caption><thead><tr><th>Stock unit</th><th>Year range</th><th>Parameter or data input to run reconstruction</th><th>Min to max range</th></tr></thead><tbody><tr><td>USA</td><td>1971 to present</td><td>Returns of small salmon, large salmon, 2SW salmon overall for USA</td><td>Midpoint only (narrow range of uncertainty added, 0.99 to 1.01 of midpoint)</td></tr><tr><td>Canada – Scotia-Fundy (SF)</td><td>1970 to present</td><td>Returns of small salmon, large salmon, 2SW salmon for two geographic areas (SFAs 19-21, SFA 23)<br/>- Includes commercial harvests of salmon that occurred in adjoining waters of the SFAs<br/>- 2SW salmon estimated from large salmon based on a fixed proportion of 2SW in large salmon</td><td>Provided as min to max range for two geographic areas</td></tr><tr><td>Canada – Southern Gulf of St Lawrence (GULF)</td><td>1970 to present</td><td>Returns of small salmon, large salmon, 2SW salmon for 4 SFAs (15 to 18)<br/>- Includes commercial and Indigenous fisheries harvests of salmon that occurred in adjoining waters of the SFAs<br/>- 2SW salmon estimated from large salmon based on a fixed proportion of 2SW in large salmon for SFAs 15, 17 and 18 and annually derived proportion from sampling in SFA 16</td><td>Provided as min to max range by SFA</td></tr><tr><td>Canada – Quebec (QC)</td><td>1971 to 1983</td><td>Annual returns of small salmon and large salmon by assessment category for all of Quebec.<br/>- commercial harvests of salmon in jurisdictional waters of the province of Quebec added to the total returns of Quebec<br/>- 2SW salmon estimated based on fixed proportion of 2SW salmon in the large salmon category.</td><td>Provided as min to max estimates of returns and spawners</td></tr><tr><td></td><td>1984 to present</td><td>River specific estimates of returns of small salmon and large salmon are used to derive min to max ranges for 11 fishing zones (1 to 11)<br/>- commercial harvests of salmon in jurisdictional waters of the province of Quebec added to the total returns of Quebec<br/>- 2SW salmon estimated based on fixed proportion of 2SW salmon in the large salmon category.</td><td>Min to max range by river summed to give min to max range by zone (10 zones in total)</td></tr></tbody></table>
<figure><img src="image_5.png" /><figcaption>Figure 3. Directed Acyclical Graph of the North American inference and forecast model for 2SW salmon.</figcaption></figure>
<table><thead><tr><th>Stock unit</th><th>Year range</th><th>Parameter or data input to run reconstruction</th><th>Min to max range</th></tr></thead><tbody><tr><td rowspan="2">Canada – Newfoundland (NFLD)</td><td rowspan="2">1971 to present</td><td>Annual returns of small salmon, large salmon and 2SW salmon for 12 SFAs (3 to 14A)</td><td rowspan="2">non-parametric bootstrap technique, with replacement, 95% C.I. used to derive min to max range by SFA (11 in total)</td></tr><tr><td>- exploitation rates in the recreational fishery for retained small salmon are derived from angling harvests in monitored rivers, exploitation rate uncertainty derived annually from available exploitation rates in monitored rivers</td></tr><tr><td rowspan="5">Canada – Labrador (LAB)</td><td rowspan="5">1971 to 1996</td><td>- exploitation rate range for retained small salmon is used to estimate returns of small salmon based on angling harvest (retained) of small salmon</td><td rowspan="5">Point estimates in number of fish by size group Exploitation rates based on recaptures of tagged smolts from Sand Hill River (1969 to 1971), recovered in the Newfoundland and Labrador commercial fisheries By SFA; 0.6 to 0.8 or 0.7 to 0.9</td></tr><tr><td>- returns of large salmon estimated from annual ratios of large to small salmon from monitored rivers</td></tr><tr><td>- 2SW salmon estimated based on fixed 2SW proportion in large salmon, by SFA</td></tr><tr><td>Annual commercial harvests of small salmon, large salmon for 3 SFAs (1,2,14B)</td></tr><tr><td>Annual exploitation rates by size group by SFA similar for 1971 to 1991, then adjusted for reductions in active licences, closure of Newfoundland commercial fishery since 1992 and changes in fishing seasons in Labrador after 1994</td></tr><tr><td></td><td></td><td>Proportion of large salmon that are 2SW salmon</td><td></td></tr><tr><td rowspan="6">1997</td><td rowspan="6"></td><td>Proportion of 1SW salmon in the large salmon category of the commercial catches</td><td>0.1 to 0.3</td></tr><tr><td>Proportion of all 1SW salmon in commercial catches that are non-maturing</td><td>0.1 to 0.2</td></tr><tr><td>Proportion Labrador origin of commercial catch of Commercial harvest number in SFA 1 and 2 (closed in SFA 14B)</td><td>0.6 to 0.8</td></tr><tr><td>Adjusted exploitation rate in SFA 1, 2 based on reductions in licenced effort</td><td>Range derived as for 1970 to 1996</td></tr><tr><td>Biological characteristics parameters as for 1970 to 1996</td><td></td></tr><tr><td>For SFA 14B, returns estimated as the sum of returns to 2 monitored rivers raised by watershed areas of rivers in SFA 14B</td><td>Range provided by expert opinion</td></tr><tr><td rowspan="2">1998 to 2001</td><td rowspan="2"></td><td>Recreational fishery catches and exploitation rates.</td><td rowspan="2">Provided as min to max estimates of returns.</td></tr><tr><td>- Return estimates of small and large salmon for 2002 to 2008, from monitoring of 3 to 4 rivers and raised by watershed areas of rivers in Labrador, were used to derived exploitation rates of small retained fish and large retained plus hooked-and-released in the Labrador recreational fishery. The range of these exploitation rates for the years 2002-2008 was applied to the angling catches in 1998-2001 to provide estimates of returns for 1998 to 2001.</td></tr><tr><td rowspan="2">2002 to present</td><td rowspan="2"></td><td>Annual returns to rivers of Labrador for small salmon and large salmon</td><td rowspan="2">non-parametric bootstrap technique, with replacement, 95% C.I. used to derive min to max</td></tr><tr><td>- return by size group per drainage area of 3 to 4 monitored rivers used to raise to all rivers of Labrador based on total drainage areas of rivers</td></tr><tr><td></td><td></td><td>Proportion 2SW in large salmon returns to rivers</td><td>0.60 to 0.71</td></tr></tbody></table>

### 4.2.5 Biological characteristics

Updates were made in 2021 to the historical values of fecundities and other biological characteristics of small and large salmon in each of the stock-units in NAC (Table 4.6) and further
<figure><img src="image_6.png" /><figcaption>Figure 4. Median (2.5th to 97.5th percentile range) of spawners (circles) and lagged spawners (squares) of 2SW salmon to NAC overall and for each of the six regions. For spawners, year corresponds to the year of spawning. For lagged spawners, year corresponds to the year of PFA. The dashed line is the corresponding 2SW Conservation Limit for NAC overall and for each region; the 2SW CL for USA (29 990 fish) is off the scale in the plot for USA. The dotted line in the Scotia-Fundy and USA panels are the region-specific 2SW management objectives.</figcaption></figure>
update was provided by USA in 2023. Additionally, the methods used to up-scale values from individual Salmon Fishing Areas (SFAs) and Management Zones (Qs) to regional values for Quebec, Gulf and Scotia-Fundy were more formally documented (NAC Stock Annex). These biological characteristics are required as input to the lifecycle model. Currently, fixed values are used for the entire biological time series (Table 4.6).

The smolt age proportions reflect stock-specific populations dynamics and the freshwater environment that modify the freshwater survival rates, precocious maturation rates and the probabilities of smolting at age. These freshwater / stock conditioned smolt age proportions by egg year class would likely not be the same as the annual smolt age proportions of returning anadromous salmon. However, absent such information for each stock unit, the smolt age proportions assumed for the stock-units were derived from a large database of available smolt ages from sampled returning salmon over a large number of years and are considered to be the most appropriate values for the stock-units of NAC. No changes were made to the smolt age proportions by stock unit from those used for the PFA forecast model (Table 4.6). Two vectors of smolt age proportions are defined for the USA stock unit for two time periods; 1971 to 1989, 1990 to present. The change for the USA stock unit was made in 2004 to reflect declines in natural spawning and changes in hatchery and stocking practices (ICES 2005). ICES (2005) also reported on examination of smolt ages for the Labrador and Gulf stock unit and concluded that there was insufficient evidence to warrant changing the smolt age proportions at that time.

The smolt age proportions previously defined are assumed to apply to all the eggs, regardless of sea-age origin, for the LCM.

<table><caption>Table 4.6. Biological characteristics inputs by sea-age group for the six stock-units of NAC.</caption><thead><tr><th rowspan="2">Parameter</th><th rowspan="2">Age group</th><th colspan="6">Stock unit</th></tr><tr><th>USA</th><th>SF</th><th>GULF</th><th>QC</th><th>NFLD</th><th>LAB</th></tr></thead><tbody><tr><td rowspan="2">Eggs per female</td><td>1SW</td><td>3165</td><td>3194</td><td>3354</td><td>3618</td><td>2500</td><td>2500</td></tr><tr><td>MSW</td><td>7829</td><td>6434</td><td>7979</td><td>8479</td><td>5000</td><td>5000</td></tr><tr><td rowspan="2">Prop. female</td><td>1SW</td><td>0.0109</td><td>0.350</td><td>0.113</td><td>0.140</td><td>0.859</td><td>0.505</td></tr><tr><td>MSW</td><td>0.64</td><td>0.889</td><td>0.740</td><td>0.670</td><td>0.804</td><td>0.859</td></tr><tr><td rowspan="2">Eggs per fish</td><td>1SW</td><td>3165</td><td>1119</td><td>379</td><td>496</td><td>1782</td><td>1262</td></tr><tr><td>MSW</td><td>7829</td><td>5722</td><td>5904</td><td>5653</td><td>4180</td><td>4295</td></tr><tr><td rowspan="2">Smolt age Prop.</td><td colspan="2">1971-1989</td><td colspan="5">1990-present</td></tr><tr><td>Smolt age 1</td><td>0.3767</td><td>0.6274</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td></td><td>Smolt age 2</td><td>0.5200</td><td>0.3508</td><td>0.6002</td><td>0.3979</td><td>0.0577</td><td>0.0408</td></tr><tr><td></td><td>Smolt age 3</td><td>0.1033</td><td>0.0218</td><td>0.3942</td><td>0.5731</td><td>0.4644</td><td>0.5979</td></tr><tr><td></td><td>Smolt age 4</td><td>0</td><td>0</td><td>0.0055</td><td>0.0291</td><td>0.3783</td><td>0.3237</td></tr><tr><td></td><td>Smolt age 5</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0.0892</td><td>0.0375</td></tr><tr><td></td><td>Smolt age 6</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0.0104</td><td>0</td></tr></tbody></table>

### 4.2.6 Conservation Limits for NAC

For the provision of catch advice for the West Greenland fisheries, ICES (2002) defined the conservation limits for six North American stock-units, in number of fish, for the two-sea-winter sea-age component only. This was done to support the catch advice for the West Greenland fishery, which exploited primarily 1SW non-maturing salmon, the majority of which would have likely returned to North America as 2SW first time spawners. In addition to the Conservation Limits, ICES (2002) also provided management objectives for the two southern stock-units of Scotia-Fundy and USA. The management objectives were defined in recognition that these stock-units were at such low abundance that there was no probability that returns would equal or exceed the CLs even in the absence of fishing at West Greenland or in homewaters. The management objectives, in terms of 2SW salmon spawners, were described as rebuilding objectives.
<figure><img src="image_7.png" /><figcaption>Figure 5. Regional estimates of returns (grey circle) and spawners (open square) of 2SW salmon 1971 to 2020 (ICES 2021). The medians and 90% confidence interval ranges are shown. The dashed blue line is the corresponding 2SW conservation limit for each region. For Scotia-Fundy and US the dotted red line corresponds to the 2SW management objectives.</figcaption></figure>
Conservation limits in terms of total eggs, or in terms of small salmon and large salmon, for the six stock-units of NAC have not been previously defined by ICES. In the interest to move to a life cycle model (LCM) with total eggs as the starting point of the life cycle, there is a need to define the conservation limits in units of total eggs and to provide the equivalences of the total eggs in terms of 1SW and MSW salmon, accounting for the biological characteristics of the two size groups and the anticipated or desired sea-age proportions of the eggs.

The Limit Reference Point (LRP; Table 4.7) is considered equivalent to the CLs for purpose of assessing stock status and providing catch advice with the LCM. The LRPs are defined in terms of eggs from all sea-age groups of spawners. The total eggs are converted to number of fish equivalents of 1SW and MSW salmon based on biological characteristics of the salmon, weighted by the desired relative proportions of the sea-age groups in the returns to rivers.

The equations for translating total egg CL requirements to sea-age equivalencies (1SW, MSW) require the following input data:

CL<sub>eggs</sub> Conservation limit in total eggs

Fec<sub>a</sub> Fecundity of a female spawner in eggs per kg by sea-age category a (1SW, MSW)

u. kg<sub>a</sub> Mean weight (kg) of female spawner by sea-age category a

p. Fem<sub>a</sub> Proportion female by sea-age category a

p. MSW Proportion of eggs contributed by MSW salmon

The calculation of equivalencies of CL eggs into spawner numbers by sea-age (CL<sub>a</sub>) is:

$$CL_{MSW} = \frac{CL_{eggs} * p. MSW}{Fec_{MSW} * u. kg_{MSW} * p. Fem_{MSW}}$$

$$CL_{1SW} = \frac{CL_{eggs} * (1 - p. MSW)}{Fec_{1SW} * u. kg_{1SW} * p. Fem_{1SW}}$$

The proportion of eggs contributed by MSW salmon within any year is calculated from the estimated abundance of each age group (N.1SW, N.MSW):

$$p. MSW = \frac{N. MSW * Eggs_{MSW}}{N. MSW * Eggs_{MSW} + N. 1SW * Eggs_{1SW}}$$

Where:

N. MSW Number of MSW spawners,

Eggs<sub>MSW</sub> Eggs per MSW spawner = Fec<sub>MSW</sub> * u. kg<sub>MSW</sub> * p. Fem<sub>MSW</sub>,

N.1SW Number of 1SW spawners and

Eggs<sub>1SW</sub> Eggs per 1SW spawner = Fec<sub>1SW</sub> * u. kg<sub>1SW</sub> * p. Fem<sub>1SW</sub>

In terms of CLs which are intended to represent production potential based on demographics, life history and populations dynamics considerations, we would be more interested in characterizing the egg contributions from the recruitment (non-fished characteristics), by sea-age groups by egg year classes if possible, but minimally by smolt cohort.

For NAC, the conversions from total eggs to fish has used estimates of sea-age proportions from inriver returns (i.e. prior to inriver fisheries but after marine fisheries) although this is not always
<figure><img src="image_8.png" /><figcaption>Figure 6. Region specific PFA to LS ratio for PFA years 1978 to 2019. The values for 2020 to 2023 are predicted based on Lagged Spawners.</figcaption></figure>
clearly stated. CLs in terms of fish equivalents by sea-age group are subject to further review and adoption by NAC countries.

Details of stock unit estimates of CLs are in the NAC Stock Annex and summarized in Table 4.7 and Table 4.8.

*   **USA:** The CL is based on an egg deposition rate of 240 eggs per 100 m² of estimated accessible fluvial rearing habitat. The calculation assumes a 50:50 ratio of males to females and a mean fecundity of 7,200 eggs per female. The CL only considers 2SW fish, but this is not considered a major issue given the extremely low proportion of 1SW, 3SW and repeat female spawners within the United States (USASAC 2022). The CL is considered a minimum estimate, but represents the best available estimate at this time. Considering the extremely depleted state of USA populations, an alternative Management Objective was also established (NASCO 2013), which aligns with the recovery criteria for the remnant stocks currently under federal protection. The CL and Management Objective are summarized in Table 4.8.

*   **Scotia-Fundy:** The LRP is based on an egg deposition rate of 240 eggs per 100 m² of fluvial rearing habitat. The egg conservation limits and the corresponding number of fish are summarized in Table 4.8. The proportion of the desired egg contributions from 1SW and MSW salmon were tabled by Gibson and Claytor (2013); it is assumed that the desired proportions by sea-age are based on returns to rivers (prior to inriver fisheries).

*   **Gulf:** The LRP is defined as the egg deposition that would result in a low probability (<25%) of the smolt production being less than half of the asymptotic production based on a Beverton-Holt stock and recruitment model with a covariate that accounts for the proportion of the eggs that would be deposited by large salmon; as the proportion of eggs deposited by large salmon increases, the optimal egg deposition rate decreases. Egg deposition rates for the rivers of Gulf vary from 152 eggs per 100 m² (prop. of eggs from large > 0.90) to 176 eggs per 100 m² (prop. of eggs from large = 0.78) (DFO 2018). The total LRP in terms of eggs is converted to number of fish by sea-age equivalents using the average biological characteristics of the small salmon and large salmon returns (Table 4.8).

*   **Quebec:** A Bayesian hierarchical model (adult to adult eggs; Ricker SR function) with reference points transported to individual rivers based on estimated habitat within the model was used to define reference points for 105 rivers in Québec. A limit reference point (LRP) was selected as the spawner abundance equivalent to the 75th percentile of the posterior distribution of $S_{0.5Rmax}$ (sp abundance at 50% maximum recruitment).

*   Egg depositions from all sea-age groups are included in the assessment of status relative to the LRP. Catch advice of the West Greenland and homewater fisheries would be provided relative to the LRP defined in terms of eggs. The total LRP in terms of eggs is converted to number of fish by sea-age equivalents using the average biological characteristics of the small salmon and large salmon returns (Table 4.8). The definition of the 2SW conservation limit for Quebec is revised from ICES (2023) to correspond to the defined LRP.

*   **Newfoundland:** Conservation egg requirements are defined as the product of the number of fluvial habitat units (unit = 100 m²) and an egg deposition rate of 240 eggs per unit plus the product of the number of hectares of lacustrine habitat and an egg deposition rate of 368 eggs per ha or 175 eggs per ha for the rivers of SFA 14A, the Northern Peninsula of Newfoundland (O'Connell and Dempson 1995; DFO 2015). O'Connell et al. (1997) provide spawner requirements in terms of small salmon, large salmon and for 2SW sea-age group for each of the SFAs in Newfoundland. Based on average eggs per fish by size group (Table 4.7), the total egg requirement equivalent to the conservation limit for Newfoundland would be 417.78 million eggs (Table 4.8).
<figure><img src="image_9.png" /><figcaption>Figure 7. Region specific PFA to LS ratio for PFA years 1978 to 2017. The values for 2020 to 2023 are predicted.</figcaption></figure>
* Labrador: The methods for deriving the conservation limits (referred to at the time as spawner targets) used by ICES for 2SW salmon, large salmon and small salmon are described in O'Connell *et al.* (1997) and the stock annex. The conservation limits in terms of number of fish were defined from the ratio of spawners to recruits (in the absence of marine fisheries) of Labrador salmon. The recruits were estimated from the run reconstruction of returns to Labrador, to which was added the catch of Labrador origin 1SW non-maturing salmon at West Greenland, corrected for 10 months of mortality (at a rate of 1% per month) between the start of the West Greenland fishery (Aug. 1) and the returns to the coast of Labrador (June 1). The period of returns to Labrador during 1974 to 1978 and West Greenland catches during 1973 to 1977 was chosen as the reference period to define the mean recruitment potential of the Labrador stock unit. Recently, Reddin *et al.* (2006) provide background and justification for the definition of a conservation limit egg deposition rate of 190 eggs per 100 m² of fluvial parr rearing habitat for rivers of Labrador, based on analysis of stock and recruitment data from the Sand Hill River with the conservation limit equivalent to the egg deposition that corresponds to 50% of the equilibrium point (eggs in recruitment equal eggs in spawners) of a fished population (mean return rate of smolts to the river as spawners of 0.073; Reddin *et al.* 2006). Reddin *et al.* (2010) list 89 rivers in Labrador (SFAs 1, 2 and 14B) and their associated egg requirements to meet conservation limits. The total egg requirement of these 89 rivers is 239.14 million eggs (Table 4.8). Average biological characteristics by size group are in Table 4.8. As a first estimate of the proportion of the eggs contributed by large salmon in Labrador, we considered the ratio of eggs contributed by large salmon based on the estimated recruits of small salmon and large salmon to Labrador as described above.

<table><caption>Table 4.7. Atlantic Salmon reference points that equate to conservation limits for the stock-units within the North American Commission area of NASCO.</caption><thead><tr><th>NAC Region</th><th>Objective</th><th>Reference Point</th><th>Reference</th></tr></thead><tbody><tr><td>USA</td><td>Egg deposition to fully seed the estimated fluvial accessible rearing habitat</td><td>240 eggs per 100 m² of fluvial habitat</td><td>Baum (1995)</td></tr><tr><td>Scotia-Fundy</td><td>LRP: egg depositions that result in half of maximum smolt production, Beverton-Holt habitat function</td><td>LRP: 240 eggs per 100 m² of fluvial habitat</td><td>Gibson and Claytor (2013)</td></tr><tr><td>Gulf</td><td>LRP: egg depositions that result in a low probability (&lt;25%) of smolt recruitment being less than 50% of maximum recruitment (Beverton-Holt function)<br>Upper Stock Reference point (USR): eggs in recruitment at MSY</td><td>Depends on river-specific sea-age characteristics of spawners;<br>LRP: 152 to 178 eggs per 100 m² of fluvial habitat<br>USR: LRP * 3.78</td><td>DFO (2015, 2018, 2022); Chaput et al. (2023)</td></tr><tr><td>Québec</td><td>LRP1: egg depositions that result in a high probability (75th percentile of posterior distribution) of the adult recruitment being more than 50% of maximum recruitment (Ricker function)<br>LRP2: egg deposition allowing to preserve 90% of the genetic diversity over 100 years.<br>River not reaching this genetic conservation limit are classified below all reference points<br>USR: egg depositions that result in a very high probability (95th percentile of posterior distribution) of the adult recruitment being more than MSY (Ricker function)</td><td>LRP varies depending upon productive units of river (average 132 eggs per 100 productive units of fluvial habitat)<br>USR: varies depending upon productive units of river (average 312 eggs per 100 productive units of fluvial habitat)</td><td>Dionne et al. (2015); MFFP (2016);<br>Ferchaud et al. (2016)</td></tr><tr><td>Insular Newfoundland</td><td>LRP: maximum freshwater production, miscellaneous approach<br>USR: defined as 1.5 * LRP</td><td>LRP: 240 eggs per 100 m² fluvial habitat<br>+ 368 eggs per ha of lacustrine habitat<br>or +150 eggs per ha of lacustrine habitat</td><td>O'Connell and Dempson (1995);<br>DFO (2020)</td></tr></tbody></table>
<figure><img src="image_10.png" /><figcaption>Figure 8. Total PFA for NAC (top panel) and PFA to LS ratio (log; bottom panel) prior to exploitation. The dashed blue line in the top panel is the corresponding 2SW conservation limit corrected for 10 months of M between the PFA period and returns to homewaters for NAC.</figcaption></figure>
<table><caption>Table 4.8. CLs for stock-units of NAC in units of total eggs and equivalences in number of 1SW and MSW salmon to be used in the LCM for provision of catch advice for NASCO. The 2SW salmon CL and the management objectives are from ICES (2023) with updated values.</caption><tr><td></td><td></td><td>habitat for the Northern Peninsula (SFA 14A)</td></tr><tr><td>Labrador</td><td>LRP: eggs for 50% of adult equilibrium point for a fished population, Beverton-Holt function</td><td>190 eggs per 100 m² of fluvial habitat Reddin et al. (2006)</td></tr></table>

<table><thead><tr><th rowspan="2">Stock unit</th><th colspan="4">Conservation limits</th><th>Management objective</th></tr><tr><th>Eggs (million)</th><th>1SW salmon (fish)</th><th>MSW salmon (fish)</th><th>2SW (updated)</th><th>2SW</th></tr></thead><tbody><tr><td>USA</td><td>na</td><td>na</td><td>na</td><td>29,199</td><td>4,549</td></tr><tr><td>Scotia-Fundy</td><td>253.529</td><td>77,565</td><td>30,484</td><td>24,785</td><td>10,976</td></tr><tr><td>Gulf</td><td>171.815</td><td>27,943</td><td>27,395</td><td>18,737</td><td></td></tr><tr><td>Quebec</td><td>124.604*</td><td>21,047*</td><td>21,077*</td><td>32,085<br>(18 914)</td><td></td></tr><tr><td>Newfoundland</td><td>417.78</td><td>198,160</td><td>15,468</td><td>4,022</td><td></td></tr><tr><td>Labrador</td><td>239.14</td><td>55,806</td><td>39,281</td><td>34,746<br>(28,310)</td><td></td></tr></tbody></table>

## 4.3 Mixed stock marine fisheries

Harvests and biological characteristics of salmon in marine mixed stock fisheries are provided as annual inputs for the PFA forecast model and for the LCM. Three marine fisheries of the Northwest Atlantic (Labrador, Newfoundland and Saint Pierre and Miquelon) only intercept salmon from the NAC stock-units: Two marine mixed stock fisheries, Greenland and Faroes), affect salmon from both NAC and NEAC stock-units. Further descriptions and time series of these fisheries are provided in the ICES Stock Annex.

### 4.3.1 Marine fisheries affecting only NAC stock-units

The commercial salmon fishery in Newfoundland has been under moratorium since 1992. The Labrador commercial salmon fishery closed in 1998 but there is an ongoing coastal subsistence food fishery since 1998. There is a gillnet fishery for salmon in the territorial waters of France around the islands of Saint Pierre and Miquelon. The commercial harvests (and subsistence fishery harvests since 1998 in Labrador) are provided in numbers of small salmon and large salmon for two large areas of Newfoundland and for three Salmon Fishing Areas of Labrador (Table 4.9; Table 4.10).

The run reconstruction of returns to the six stock-units of NAC represent abundances after the marine fisheries of Newfoundland, Labrador and Saint Pierre and Miquelon, therefore the attribution of origin of the catches is not required for the run reconstruction step to estimate returns (except for the estimation of returns to rivers of Labrador which assumes a proportion of the commercial harvests are of Labrador origin).

<footnote>* Excludes values for the four northern rivers of Ungava Bay (management zone Q11)
na – not available at time of writing owing to updates and access, to be confirmed in the Stock Annex.</footnote>
<figure><img src="image_11.png" /><figcaption>Figure 9. Region specific PFA values for PFA years 1978 to 2023. The values for 2020 to 2023 are predicted based on Lagged Spawners. The dashed blue line is the corresponding 2SW conservation limit corrected for 10 months of M between the PFA period and returns to homewaters for each region. For Scotia-Fundy and US the dotted red line corresponds to the 2SW management objectives corrected for M.</figcaption></figure>
Attribution of the harvests in the Labrador, Newfoundland and Saint Pierre and Miquelon marine fisheries to the NAC stock-units is done in the PFA forecast model (specifically for 2SW salmon) and in the LCM; for both based on assumptions of availabilities of the stock-units to those fisheries.

For Labrador: The commercial harvest number of small salmon, large salmon are tabulated by SFA for Labrador. For the subsistence fisheries since 1998, the harvests by size group are tabulated for the combined SFAs of Labrador.

* Labrador commercial fishery harvests of small salmon and large salmon for 1971 to 1997 are considered to comprise 60% to 80% Labrador origin fish, with the remainder attributed to the other five stock-units in proportion to the sum of the PFA for those five stock-units.

* Labrador subsistence (Indigenous Food, Social and Ceremonial fisheries, Labrador resident food fisheries) fishery harvests for 1998 to present are considered to comprise 90% to 100% Labrador origin fish, with the remainder (0 - 10%) attributed to the other five stock-units in proportion to the sum of the PFA for those five stock-units.

* Proportion 2SW salmon in the large salmon category is assumed 0.6 to 0.8 or 0.7 to 0.9, by SFA for 1971 to 1997. For the subsistence fisheries of 1998 to present, the proportion 2SW in the harvests is assumed to be 0.60 to 0.71.

For Newfoundland: The harvest number of small salmon, large salmon are tabulated for two regions of the Newfoundland coast, the northeast region comprised of SFAs 3 to 7 and the south and west coast comprised of SFAs 8 to 14A.

* Harvests of salmon in the SFAs 3 to 7 region are attributed to the six stock-units of NAC based on the proportion of the estimated stock unit PFAs, including Labrador.

* For SFAs 8 to 14A, it is assumed that no Labrador origin salmon are harvested in those fisheries and the harvests are attributed to the other five stock-units in proportion to the sum of their estimated stock unit specific PFAs.

* The proportion 2SW in the large salmon category is assumed to be 0.7 to 0.9 for the harvests in SFA 3 to 7. All large salmon are assumed to be 2SW salmon in the harvests from SFAs 8 to 14A.

For Saint Pierre and Miquelon: Harvests in total weight are converted to number of small and large salmon based on samples (limited in many years) from the fishery. Salmon harvested by the Saint Pierre and Miquelon salmon fishery have been attributed to all stock-units of eastern North America, although few have been identified from Labrador or the USA (ICES 2021, 2023).

* It is assumed that no Labrador origin salmon are harvested in this fishery and the harvests are attributed to the other five stock-units in proportion to the sum of their estimated stock unit specific PFAs.

* All large salmon are assumed to be 2SW salmon.

### 4.3.2 Marine fisheries affecting NAC and NEAC stock-units

#### Faroes fishery

The fishery in the Faroes area commenced in 1968 with a small number of vessels fishing up to 70 miles north of the Faroes. Catches peaked at 1025 tonnes in 1981. There has been no commercial salmon fishery targeting salmon around the Faroes since the early 1990s.

The Faroes salmon fishery operated from November through to May. The salmon caught in the fishery originated almost entirely from European countries with salmon from many countries
<figure><img src="image_12.png" /><figcaption>Figure 10. Proportion of PFA in each region relative to overall PFA for NAC.</figcaption></figure>
being present in the area although small numbers of tagged fish originating in North America
were also recaptured in the fishery.

The fishery exploited mainly 2SW fish, although some 1SW and 3SW fish were also caught. Small salmon (<60 cm total length) in their first winter at sea were required to be discarded. Large numbers of farmed salmon were also observed at Faroes and farmed fish accounted for a significant proportion of the catch; in the early 1990s, the proportion of farmed fish in this area was estimated at between 25 and 40% (Hansen *et al.*, 1999).

Inputs to the run reconstruction, PFA forecast model and for the LCM consist of estimated number of 1SW salmon, MSW salmon captured in the fishery (by year), percentages of 1SW salmon catch that is unreported (and associated % uncertainty of this value) and the proportion of the catch that was wild salmon (i.e. not farmed escapee origin) (Table 4.11). The time series of data for this fishery extends from 1971 to 2022.

Other multi-annual data include mid-month of returns to stock-unit, estimates of catch proportions by stock-unit of origin in the Faroes fisheries, mid-point month of fishery-catch and associated variation and mortality proportion of released/discarded fish for Faroes.

### Greenland fishery

Limited fishing at West Greenland is reported as far back as the early 1900s, although the present fishery dates from 1959. Rapid expansion along the coast followed and was associated with changes in gear technology, resulting in a maximum reported landing of almost 2700 tonnes in 1971. Small catches of salmon are also made on the east coast of Greenland although these are sporadic and low and are not included in the run reconstruction or PFA modelling by ICES.

Regulatory measures agreed by the West Greenland Commission of NASCO resulted in greatly reduced allowable catches in the West Greenland fishery, reflecting declining abundance of the contributing salmon stocks. In all but two years since 1998, the fishery has been restricted to an internal-use fishery and commercial export of salmon has not been permitted.

The Greenland salmon fishery operates in summer, generally August through October, with a fairly large proportion of the catch commonly being taken in the weeks after the opening of the season in August. The salmon caught at West Greenland are almost exclusively fish in their second summer at sea: non-maturing 1SW salmon destined to return to homewaters as 2SW, or older, fish. Fish from all parts of North America are taken in the fishery, while it is primarily only potential MSW salmon from southern countries in Europe (UK, Ireland and France) that are exploited here. Very few salmon of farmed origin appear in the catches at Greenland and these are not taken into account in assessments.

Inputs to the run reconstruction, PFA forecast model and for the LCM consist of reported catch weight at West Greenland, best estimates of unreported catch weight and biological characteristics of sampled salmon to convert catch in weight to catch in number of NAC and NEAC origin salmon. The time series of data for this fishery extends from 1971 to 2022 (Table 4.12).

Other multi-annual data include mid-month of returns to stock-unit and mid-point month of fishery-catch and associated variation.
<figure><img src="image_13.png" /><figcaption>Figure 11. Comparison of the estimated (median value) productivity parameter by region and overall for NAC (mean of regional values, black line) from the assessment in 2018 (upper panel; ICES 2018) and the corresponding productivity values estimated with updated values in the assessment from ICES (2021; lower panel) for the PFA years 1978 to 2020. The points in both panels in the shaded rectangle are forecast values for the productivity parameter for the corresponding assessment periods.</figcaption></figure>
<table><caption>Table 4.9. Harvests (number of fish) of large salmon in the marine fisheries of Labrador (LAB), Newfoundland (NFLD) and Saint Pierre and Miquelon (SPM), 1970 to 2022.</caption><thead><tr><th rowspan="2">Year</th><th colspan="5">LAB</th><th>NFLD</th><th rowspan="2">SPM</th></tr><tr><th>SFA 01</th><th>SFA 02</th><th>SFA 14B</th><th>Subsistence</th><th>SFA 3-7</th><th>SFA 8-14A</th></tr></thead><tbody><tr><td>1970</td><td>17633</td><td>45479</td><td>9595</td><td>0</td><td>na</td><td>na</td><td>0</td></tr><tr><td>1971</td><td>25127</td><td>64806</td><td>13673</td><td>0</td><td>81152</td><td>na</td><td>0</td></tr><tr><td>1972</td><td>21599</td><td>55708</td><td>11753</td><td>0</td><td>43041</td><td>42861</td><td>0</td></tr><tr><td>1973</td><td>30204</td><td>77902</td><td>16436</td><td>0</td><td>85904</td><td>43627</td><td>0</td></tr><tr><td>1974</td><td>13866</td><td>93036</td><td>15863</td><td>0</td><td>73961</td><td>85714</td><td>0</td></tr><tr><td>1975</td><td>28601</td><td>71168</td><td>14752</td><td>0</td><td>100504</td><td>72814</td><td>0</td></tr><tr><td>1976</td><td>38555</td><td>77796</td><td>15189</td><td>0</td><td>79318</td><td>95714</td><td>348</td></tr><tr><td>1977</td><td>28158</td><td>70158</td><td>18664</td><td>0</td><td>114413</td><td>63449</td><td>0</td></tr><tr><td>1978</td><td>30824</td><td>48934</td><td>11715</td><td>0</td><td>64073</td><td>37653</td><td>0</td></tr><tr><td>1979</td><td>21291</td><td>27073</td><td>3874</td><td>0</td><td>29936</td><td>29122</td><td>0</td></tr><tr><td>1980</td><td>28750</td><td>87067</td><td>9138</td><td>0</td><td>86941</td><td>54307</td><td>0</td></tr><tr><td>1981</td><td>36147</td><td>68581</td><td>7606</td><td>0</td><td>98672</td><td>38663</td><td>0</td></tr><tr><td>1982</td><td>24192</td><td>53085</td><td>5966</td><td>0</td><td>46076</td><td>35055</td><td>0</td></tr><tr><td>1983</td><td>19403</td><td>33320</td><td>7489</td><td>0</td><td>48218</td><td>28215</td><td>348</td></tr><tr><td>1984</td><td>11726</td><td>25258</td><td>6218</td><td>0</td><td>44540</td><td>15135</td><td>348</td></tr><tr><td>1985</td><td>13252</td><td>16789</td><td>3954</td><td>0</td><td>36975</td><td>24383</td><td>348</td></tr><tr><td>1986</td><td>19152</td><td>34071</td><td>5342</td><td>0</td><td>48996</td><td>22036</td><td>290</td></tr><tr><td>1987</td><td>18257</td><td>49799</td><td>11114</td><td>0</td><td>67072</td><td>19241</td><td>232</td></tr><tr><td>1988</td><td>12621</td><td>32386</td><td>4591</td><td>0</td><td>36449</td><td>14763</td><td>232</td></tr><tr><td>1989</td><td>16261</td><td>26836</td><td>4646</td><td>0</td><td>37576</td><td>15577</td><td>232</td></tr><tr><td>1990</td><td>7313</td><td>17316</td><td>2858</td><td>0</td><td>31847</td><td>11639</td><td>218</td></tr><tr><td>1991</td><td>1369</td><td>7679</td><td>4417</td><td>0</td><td>25792</td><td>10259</td><td>135</td></tr><tr><td>1992</td><td>9981</td><td>19608</td><td>2752</td><td>0</td><td>0</td><td>0</td><td>269</td></tr><tr><td>1993</td><td>3825</td><td>9651</td><td>3620</td><td>0</td><td>0</td><td>0</td><td>342</td></tr><tr><td>1994</td><td>3464</td><td>11056</td><td>857</td><td>0</td><td>0</td><td>0</td><td>398</td></tr><tr><td>1995</td><td>2150</td><td>8714</td><td>312</td><td>0</td><td>0</td><td>0</td><td>97</td></tr><tr><td>1996</td><td>1375</td><td>5479</td><td>418</td><td>0</td><td>0</td><td>0</td><td>182</td></tr></tbody></table>
<figure><img src="image_14.png" /><figcaption>Figure 12. Comparison of the estimated (median value) productivity parameter by region and overall for NAC (mean of regional values, black line) from the assessment in 2018 (x-axis; ICES 2018) and the corresponding productivity values estimated with data to 2020 (y-axis; ICES 2021). The symbols are colour coded for year (red early, blue later) and the forecast values from ICES (2018) and the estimated values from ICES 2021) are shown as green square symbols.</figcaption></figure>
<table><tr><td>1997</td><td>1393</td><td>5550</td><td>263</td><td>0</td><td>0</td><td>0</td><td>173</td></tr><tr><td>1998</td><td>0</td><td>0</td><td>0</td><td>2269</td><td>0</td><td>0</td><td>268</td></tr><tr><td>1999</td><td>0</td><td>0</td><td>0</td><td>1084</td><td>0</td><td>0</td><td>270</td></tr><tr><td>2000</td><td>0</td><td>0</td><td>0</td><td>1352</td><td>0</td><td>0</td><td>263</td></tr><tr><td>2001</td><td>0</td><td>0</td><td>0</td><td>1721</td><td>0</td><td>0</td><td>250</td></tr><tr><td>2002</td><td>0</td><td>0</td><td>0</td><td>1389</td><td>0</td><td>0</td><td>227</td></tr><tr><td>2003</td><td>0</td><td>0</td><td>0</td><td>2175</td><td>0</td><td>0</td><td>348</td></tr><tr><td>2004</td><td>0</td><td>0</td><td>0</td><td>3696</td><td>0</td><td>0</td><td>196</td></tr><tr><td>2005</td><td>0</td><td>0</td><td>0</td><td>2817</td><td>0</td><td>0</td><td>351</td></tr><tr><td>2006</td><td>0</td><td>0</td><td>0</td><td>3090</td><td>0</td><td>0</td><td>469</td></tr><tr><td>2007</td><td>0</td><td>0</td><td>0</td><td>2652</td><td>0</td><td>0</td><td>218</td></tr><tr><td>2008</td><td>0</td><td>0</td><td>0</td><td>3909</td><td>0</td><td>0</td><td>442</td></tr><tr><td>2009</td><td>0</td><td>0</td><td>0</td><td>3344</td><td>0</td><td>0</td><td>408</td></tr><tr><td>2010</td><td>0</td><td>0</td><td>0</td><td>3725</td><td>0</td><td>0</td><td>470</td></tr><tr><td>2011</td><td>0</td><td>0</td><td>0</td><td>4451</td><td>0</td><td>0</td><td>1031</td></tr><tr><td>2012</td><td>0</td><td>0</td><td>0</td><td>4228</td><td>0</td><td>0</td><td>156</td></tr><tr><td>2013</td><td>0</td><td>0</td><td>0</td><td>6479</td><td>0</td><td>0</td><td>1272</td></tr><tr><td>2014</td><td>0</td><td>0</td><td>0</td><td>3994</td><td>0</td><td>0</td><td>611</td></tr><tr><td>2015</td><td>0</td><td>0</td><td>0</td><td>6146</td><td>0</td><td>0</td><td>410</td></tr><tr><td>2016</td><td>0</td><td>0</td><td>0</td><td>5595</td><td>0</td><td>0</td><td>286</td></tr><tr><td>2017</td><td>0</td><td>0</td><td>0</td><td>5818</td><td>0</td><td>0</td><td>78</td></tr><tr><td>2018</td><td>0</td><td>0</td><td>0</td><td>4077</td><td>0</td><td>0</td><td>214</td></tr><tr><td>2019</td><td>0</td><td>0</td><td>0</td><td>5793</td><td>0</td><td>0</td><td>182</td></tr><tr><td>2020</td><td>0</td><td>0</td><td>0</td><td>6345</td><td>0</td><td>0</td><td>214</td></tr><tr><td>2021</td><td>0</td><td>0</td><td>0</td><td>4217</td><td>0</td><td>0</td><td>241</td></tr><tr><td>2022</td><td>0</td><td>0</td><td>0</td><td>5035</td><td>0</td><td>0</td><td>152</td></tr></table>
<figure><img src="image_15.png" /><figcaption>Figure 13. Comparison of the estimated (median value) PFA by region from the assessment in 2018 (x-axis; ICES 2018) and the corresponding PFA estimated with data to 2020 (y-axis; ICES 2021). The symbols are colour coded for year (red early, blue later) and the forecast values from ICES (2018) and the estimated values from ICES (2021) are shown as green square symbols.</figcaption></figure>
<table><caption>Table 4.10. Harvests (number of fish) of small salmon in the marine fisheries of Labrador (LAB), Newfoundland (NFLD) and Saint Pierre and Miquelon (SPM), 1970 to 2022.</caption><thead><tr><th rowspan="2">Year</th><th colspan="4">LAB</th><th colspan="2">NFLD</th><th rowspan="2">SPM</th></tr><tr><th>SFA 01</th><th>SFA 02</th><th>SFA 14B</th><th>Subsistence</th><th>SFA 3-7</th><th>SFA 8-14A</th></tr></thead><tbody><tr><td>1970</td><td>14666</td><td>29441</td><td>8605</td><td>0</td><td>NA</td><td>NA</td><td>0</td></tr><tr><td>1971</td><td>19109</td><td>38359</td><td>11212</td><td>0</td><td>111518</td><td>70936</td><td>0</td></tr><tr><td>1972</td><td>14303</td><td>28711</td><td>8392</td><td>0</td><td>107770</td><td>111141</td><td>0</td></tr><tr><td>1973</td><td>3130</td><td>6282</td><td>1836</td><td>0</td><td>180966</td><td>176907</td><td>0</td></tr><tr><td>1974</td><td>9848</td><td>37145</td><td>9328</td><td>0</td><td>135874</td><td>153278</td><td>0</td></tr><tr><td>1975</td><td>34937</td><td>57560</td><td>19294</td><td>0</td><td>190557</td><td>91935</td><td>0</td></tr><tr><td>1976</td><td>17589</td><td>47468</td><td>13152</td><td>0</td><td>143557</td><td>118779</td><td>731</td></tr><tr><td>1977</td><td>17796</td><td>40539</td><td>11267</td><td>0</td><td>150491</td><td>57472</td><td>0</td></tr><tr><td>1978</td><td>17095</td><td>12535</td><td>4026</td><td>0</td><td>68747</td><td>38180</td><td>0</td></tr><tr><td>1979</td><td>9712</td><td>28808</td><td>7194</td><td>0</td><td>140844</td><td>62622</td><td>0</td></tr><tr><td>1980</td><td>22501</td><td>72485</td><td>8493</td><td>0</td><td>186648</td><td>94291</td><td>0</td></tr><tr><td>1981</td><td>21596</td><td>86426</td><td>6658</td><td>0</td><td>174222</td><td>60668</td><td>0</td></tr><tr><td>1982</td><td>18478</td><td>53592</td><td>7379</td><td>0</td><td>143445</td><td>77017</td><td>0</td></tr><tr><td>1983</td><td>15964</td><td>30185</td><td>3292</td><td>0</td><td>116592</td><td>55683</td><td>731</td></tr><tr><td>1984</td><td>11474</td><td>11695</td><td>2421</td><td>0</td><td>98184</td><td>52813</td><td>731</td></tr><tr><td>1985</td><td>15400</td><td>24499</td><td>7460</td><td>0</td><td>131360</td><td>79275</td><td>731</td></tr><tr><td>1986</td><td>17779</td><td>45321</td><td>8296</td><td>0</td><td>151275</td><td>91912</td><td>609</td></tr><tr><td>1987</td><td>13714</td><td>64351</td><td>11389</td><td>0</td><td>192308</td><td>82401</td><td>487</td></tr><tr><td>1988</td><td>19641</td><td>56381</td><td>7087</td><td>0</td><td>115375</td><td>74620</td><td>487</td></tr><tr><td>1989</td><td>13233</td><td>34200</td><td>9053</td><td>0</td><td>116375</td><td>60884</td><td>487</td></tr><tr><td>1990</td><td>8736</td><td>20699</td><td>3592</td><td>0</td><td>71761</td><td>46053</td><td>458</td></tr><tr><td>1991</td><td>1410</td><td>20055</td><td>5303</td><td>0</td><td>62331</td><td>42721</td><td>283</td></tr><tr><td>1992</td><td>9588</td><td>13336</td><td>1325</td><td>0</td><td>0</td><td>0</td><td>565</td></tr><tr><td>1993</td><td>3893</td><td>12037</td><td>1144</td><td>0</td><td>0</td><td>0</td><td>717</td></tr><tr><td>1994</td><td>3303</td><td>4535</td><td>802</td><td>0</td><td>0</td><td>0</td><td>834</td></tr><tr><td>1995</td><td>3202</td><td>4561</td><td>217</td><td>0</td><td>0</td><td>0</td><td>204</td></tr><tr><td>1996</td><td>1676</td><td>5308</td><td>865</td><td>0</td><td>0</td><td>0</td><td>382</td></tr></tbody></table>
<table><tr><td>1997</td><td>1728</td><td>8025</td><td>332</td><td>0</td><td>0</td><td>0</td><td>363</td></tr><tr><td>1998</td><td>0</td><td>0</td><td>0</td><td>2988</td><td>0</td><td>0</td><td>562</td></tr><tr><td>1999</td><td>0</td><td>0</td><td>0</td><td>2739</td><td>0</td><td>0</td><td>566</td></tr><tr><td>2000</td><td>0</td><td>0</td><td>0</td><td>5323</td><td>0</td><td>0</td><td>552</td></tr><tr><td>2001</td><td>0</td><td>0</td><td>0</td><td>4789</td><td>0</td><td>0</td><td>525</td></tr><tr><td>2002</td><td>0</td><td>0</td><td>0</td><td>5806</td><td>0</td><td>0</td><td>476</td></tr><tr><td>2003</td><td>0</td><td>0</td><td>0</td><td>6477</td><td>0</td><td>0</td><td>731</td></tr><tr><td>2004</td><td>0</td><td>0</td><td>0</td><td>8385</td><td>0</td><td>0</td><td>892</td></tr><tr><td>2005</td><td>0</td><td>0</td><td>0</td><td>10436</td><td>0</td><td>0</td><td>926</td></tr><tr><td>2006</td><td>0</td><td>0</td><td>0</td><td>10377</td><td>0</td><td>0</td><td>985</td></tr><tr><td>2007</td><td>0</td><td>0</td><td>0</td><td>9208</td><td>0</td><td>0</td><td>458</td></tr><tr><td>2008</td><td>0</td><td>0</td><td>0</td><td>9834</td><td>0</td><td>0</td><td>926</td></tr><tr><td>2009</td><td>0</td><td>0</td><td>0</td><td>7988</td><td>0</td><td>0</td><td>857</td></tr><tr><td>2010</td><td>0</td><td>0</td><td>0</td><td>9867</td><td>0</td><td>0</td><td>602</td></tr><tr><td>2011</td><td>0</td><td>0</td><td>0</td><td>11138</td><td>0</td><td>0</td><td>145</td></tr><tr><td>2012</td><td>0</td><td>0</td><td>0</td><td>9977</td><td>0</td><td>0</td><td>327</td></tr><tr><td>2013</td><td>0</td><td>0</td><td>0</td><td>7185</td><td>0</td><td>0</td><td>542</td></tr><tr><td>2014</td><td>0</td><td>0</td><td>0</td><td>8958</td><td>0</td><td>0</td><td>440</td></tr><tr><td>2015</td><td>0</td><td>0</td><td>0</td><td>8923</td><td>0</td><td>0</td><td>988</td></tr><tr><td>2016</td><td>0</td><td>0</td><td>0</td><td>7645</td><td>0</td><td>0</td><td>1396</td></tr><tr><td>2017</td><td>0</td><td>0</td><td>0</td><td>6701</td><td>0</td><td>0</td><td>1045</td></tr><tr><td>2018</td><td>0</td><td>0</td><td>0</td><td>8780</td><td>0</td><td>0</td><td>382</td></tr><tr><td>2019</td><td>0</td><td>0</td><td>0</td><td>7062</td><td>0</td><td>0</td><td>391</td></tr><tr><td>2020</td><td>0</td><td>0</td><td>0</td><td>7607</td><td>0</td><td>0</td><td>382</td></tr><tr><td>2021</td><td>0</td><td>0</td><td>0</td><td>9377</td><td>0</td><td>0</td><td>449</td></tr><tr><td>2022</td><td>0</td><td>0</td><td>0</td><td>9130</td><td>0</td><td>0</td><td>336</td></tr></table>
<table><caption>Table 4.11. Catch (number) and biological characteristics of sampled Atlantic salmon at Faroes, 1971 to 2000.</caption><thead><tr><th rowspan="2">Year</th><th colspan="2">Catch (number salmon)</th><th colspan="2">Unreported catch of 1SW salmon</th><th rowspan="2">Prop. wild</th></tr><tr><th>1SW</th><th>MSW</th><th>Estimated %</th><th>Uncertainty in % unreported</th></tr></thead><tbody><tr><td>1971</td><td>2620</td><td>105796</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1972</td><td>2754</td><td>111187</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1973</td><td>3121</td><td>126012</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1974</td><td>2186</td><td>88276</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1975</td><td>2798</td><td>112984</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1976</td><td>1830</td><td>73900</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1977</td><td>1291</td><td>52112</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1978</td><td>974</td><td>39309</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1979</td><td>1736</td><td>70082</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1980</td><td>4523</td><td>182616</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1981</td><td>7443</td><td>300542</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1982</td><td>6859</td><td>276957</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1983</td><td>15861</td><td>215349</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1984</td><td>5534</td><td>138227</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1985</td><td>378</td><td>158103</td><td>10</td><td>5</td><td>0.9</td></tr><tr><td>1986</td><td>1979</td><td>180934</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1987</td><td>90</td><td>166244</td><td>10</td><td>5</td><td>1.0</td></tr><tr><td>1988</td><td>8637</td><td>87629</td><td>10</td><td>5</td><td>0.9</td></tr><tr><td>1989</td><td>1788</td><td>121965</td><td>10</td><td>5</td><td>0.8</td></tr><tr><td>1990</td><td>1989</td><td>140054</td><td>10</td><td>5</td><td>0.5</td></tr><tr><td>1991</td><td>943</td><td>84935</td><td>10</td><td>5</td><td>0.5</td></tr><tr><td>1992</td><td>68</td><td>35700</td><td>10</td><td>5</td><td>0.6</td></tr><tr><td>1993</td><td>6</td><td>30023</td><td>10</td><td>5</td><td>0.7</td></tr><tr><td>1994</td><td>15</td><td>31672</td><td>10</td><td>5</td><td>0.7</td></tr><tr><td>1995</td><td>18</td><td>34662</td><td>10</td><td>5</td><td>0.8</td></tr><tr><td>1996</td><td>101</td><td>28381</td><td>10</td><td>5</td><td>0.8</td></tr><tr><td>1997</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0.0</td></tr><tr><td>1998</td><td>339</td><td>1424</td><td>15</td><td>5</td><td>0.8</td></tr></tbody></table>
<table><caption>Table 4.12. Harvests (tons) and biological characteristics of sampled Atlantic salmon at West Greenland, 1971 to 2022. From 1971-1984, the proportion 1SW NAC and NEAC (italics) were assumed to be equal to the 1985-1992 mean values. There was insufficient sampling in 1997 and the mean weight and min and max proportion NAC (italics) were derived from the 1975-1979 estimates. The fishery was suspended in 1993 and 1994 and there were no reported landings or sampling of the harvest. The biological characteristics (italics) for these two years were derived from the 1991-1995 estimates.</caption><tr><td>1999</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0.0</td></tr><tr><td>2000</td><td>225</td><td>1765</td><td>15</td><td>5</td><td>0.8</td></tr></table>

<table><thead><tr><th rowspan="2">Year</th><th colspan="2">West Greenland (t)</th><th rowspan="2">Mean weight (kg)</th><th colspan="2">Estimated prop. NAC (scales)</th><th colspan="2">Prop. 1SW</th><th colspan="2">Samples to continent (genetics)</th></tr><tr><th>Reported</th><th>Unreported</th><th>min</th><th>max</th><th>NAC</th><th>NEAC</th><th>NAC</th><th>NEAC</th></tr></thead><tbody><tr><td>1971</td><td>2 689.0</td><td>0.0</td><td>3.140</td><td>0.280</td><td>0.400</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1972</td><td>2 113.0</td><td>0.0</td><td>3.440</td><td>0.340</td><td>0.370</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1973</td><td>2 341.0</td><td>0.0</td><td>4.180</td><td>0.390</td><td>0.590</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1974</td><td>1 917.0</td><td>0.0</td><td>3.580</td><td>0.390</td><td>0.460</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1975</td><td>2 030.0</td><td>0.0</td><td>3.120</td><td>0.400</td><td>0.480</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1976</td><td>1 175.0</td><td>0.0</td><td>3.040</td><td>0.380</td><td>0.480</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1977</td><td>1 420.0</td><td>0.0</td><td>3.210</td><td>0.380</td><td>0.570</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1978</td><td>984.0</td><td>0.0</td><td>3.350</td><td>0.470</td><td>0.570</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1979</td><td>1 395.0</td><td>0.0</td><td>3.340</td><td>0.480</td><td>0.520</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1980</td><td>1 194.0</td><td>0.0</td><td>3.220</td><td>0.450</td><td>0.510</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1981</td><td>1 264.0</td><td>0.0</td><td>3.170</td><td>0.580</td><td>0.610</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1982</td><td>1 077.0</td><td>0.0</td><td>3.110</td><td>0.600</td><td>0.640</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1983</td><td>310.0</td><td>0.0</td><td>3.100</td><td>0.380</td><td>0.410</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1984</td><td>297.0</td><td>0.0</td><td>3.110</td><td>0.470</td><td>0.530</td><td>0.945</td><td>0.964</td><td></td><td></td></tr><tr><td>1985</td><td>864.0</td><td>0.0</td><td>2.870</td><td>0.460</td><td>0.530</td><td>0.925</td><td>0.950</td><td></td><td></td></tr><tr><td>1986</td><td>960.0</td><td>0.0</td><td>3.030</td><td>0.480</td><td>0.660</td><td>0.951</td><td>0.975</td><td></td><td></td></tr><tr><td>1987</td><td>966.0</td><td>0.0</td><td>3.160</td><td>0.540</td><td>0.630</td><td>0.963</td><td>0.980</td><td></td><td></td></tr><tr><td>1988</td><td>893.0</td><td>0.0</td><td>3.180</td><td>0.380</td><td>0.490</td><td>0.967</td><td>0.981</td><td></td><td></td></tr><tr><td>1989</td><td>337.0</td><td>0.0</td><td>2.870</td><td>0.520</td><td>0.600</td><td>0.923</td><td>0.955</td><td></td><td></td></tr><tr><td>1990</td><td>274.0</td><td>0.0</td><td>2.690</td><td>0.700</td><td>0.790</td><td>0.957</td><td>0.963</td><td></td><td></td></tr><tr><td>1991</td><td>472.0</td><td>0.0</td><td>2.650</td><td>0.610</td><td>0.690</td><td>0.956</td><td>0.934</td><td></td><td></td></tr><tr><td>1992</td><td>237.0</td><td>0.0</td><td>2.810</td><td>0.500</td><td>0.570</td><td>0.919</td><td>0.975</td><td></td><td></td></tr></tbody></table>
<table><tr><td>1993</td><td>0.0</td><td>12.0</td><td>2.730</td><td>0.500</td><td>0.760</td><td>0.950</td><td>0.960</td><td></td><td></td><td></td></tr><tr><td>1994</td><td>0.0</td><td>12.0</td><td>2.730</td><td>0.500</td><td>0.760</td><td>0.950</td><td>0.960</td><td></td><td></td><td></td></tr><tr><td>1995</td><td>83.0</td><td>20.0</td><td>2.560</td><td>0.650</td><td>0.720</td><td>0.968</td><td>0.973</td><td></td><td></td><td></td></tr><tr><td>1996</td><td>92.0</td><td>20.0</td><td>2.880</td><td>0.710</td><td>0.760</td><td>0.941</td><td>0.961</td><td></td><td></td><td></td></tr><tr><td>1997</td><td>58.0</td><td>5.0</td><td>2.710</td><td>0.750</td><td>0.840</td><td>0.982</td><td>0.993</td><td></td><td></td><td></td></tr><tr><td>1998</td><td>11.0</td><td>11.0</td><td>2.780</td><td>0.730</td><td>0.840</td><td>0.968</td><td>0.994</td><td></td><td></td><td></td></tr><tr><td>1999</td><td>19.0</td><td>12.5</td><td>3.080</td><td>0.840</td><td>0.970</td><td>0.968</td><td>1.000</td><td></td><td></td><td></td></tr><tr><td>2000</td><td>21.0</td><td>10.0</td><td>2.570</td><td></td><td></td><td>0.974</td><td>1.000</td><td>344</td><td>146</td><td></td></tr><tr><td>2001</td><td>43.0</td><td>10.0</td><td>3.000</td><td>0.670</td><td>0.710</td><td>0.982</td><td>0.978</td><td></td><td></td><td></td></tr><tr><td>2002</td><td>9.8</td><td>10.0</td><td>2.900</td><td></td><td></td><td>0.973</td><td>1.000</td><td>338</td><td>163</td><td></td></tr><tr><td>2003</td><td>12.3</td><td>10.0</td><td>3.040</td><td></td><td></td><td>0.967</td><td>0.989</td><td>1 212</td><td>567</td><td></td></tr><tr><td>2004</td><td>17.2</td><td>10.0</td><td>3.180</td><td></td><td></td><td>0.970</td><td>0.970</td><td>1 192</td><td>447</td><td></td></tr><tr><td>2005</td><td>17.3</td><td>10.0</td><td>3.310</td><td></td><td></td><td>0.924</td><td>0.967</td><td>585</td><td>182</td><td></td></tr><tr><td>2006</td><td>23.0</td><td>10.0</td><td>3.240</td><td></td><td></td><td>0.930</td><td>0.988</td><td>857</td><td>326</td><td></td></tr><tr><td>2007</td><td>24.8</td><td>10.0</td><td>2.980</td><td></td><td></td><td>0.965</td><td>0.956</td><td>917</td><td>206</td><td></td></tr><tr><td>2008</td><td>28.6</td><td>10.0</td><td>3.080</td><td></td><td></td><td>0.974</td><td>0.988</td><td>1 593</td><td>260</td><td></td></tr><tr><td>2009</td><td>28.0</td><td>10.0</td><td>3.500</td><td></td><td></td><td>0.934</td><td>0.894</td><td>1 483</td><td>138</td><td></td></tr><tr><td>2010</td><td>43.1</td><td>10.0</td><td>3.420</td><td></td><td></td><td>0.982</td><td>0.975</td><td>991</td><td>249</td><td></td></tr><tr><td>2011</td><td>27.4</td><td>10.0</td><td>3.400</td><td></td><td></td><td>0.939</td><td>0.831</td><td>888</td><td>72</td><td></td></tr><tr><td>2012</td><td>34.6</td><td>10.0</td><td>3.440</td><td></td><td></td><td>0.932</td><td>0.980</td><td>1 121</td><td>252</td><td></td></tr><tr><td>2013</td><td>47.7</td><td>10.0</td><td>3.350</td><td></td><td></td><td>0.949</td><td>0.966</td><td>938</td><td>211</td><td></td></tr><tr><td>2014</td><td>70.4</td><td>10.0</td><td>3.320</td><td></td><td></td><td>0.913</td><td>0.961</td><td>660</td><td>260</td><td></td></tr><tr><td>2015</td><td>60.9</td><td>10.0</td><td>3.370</td><td></td><td></td><td>0.970</td><td>0.982</td><td>1 337</td><td>337</td><td></td></tr><tr><td>2016</td><td>30.2</td><td>10.0</td><td>3.180</td><td></td><td></td><td>0.935</td><td>0.955</td><td>864</td><td>438</td><td></td></tr><tr><td>2017</td><td>28.0</td><td>10.0</td><td>3.490</td><td></td><td></td><td>0.925</td><td>0.931</td><td>734</td><td>252</td><td></td></tr><tr><td>2018</td><td>39.0</td><td>10.0</td><td>2.970</td><td></td><td></td><td>0.974</td><td>0.974</td><td>814</td><td>165</td><td></td></tr><tr><td>2019</td><td>28.3</td><td>10.0</td><td>2.960</td><td></td><td></td><td>0.959</td><td>0.979</td><td>766</td><td>305</td><td></td></tr><tr><td>2020</td><td>30.9</td><td>10.0</td><td>3.500</td><td></td><td></td><td>0.923</td><td>0.971</td><td>109</td><td>87</td><td></td></tr><tr><td>2021</td><td>41.8</td><td>10.0</td><td>3.420</td><td></td><td></td><td>0.955</td><td>0.979</td><td>1250</td><td>268</td><td></td></tr><tr><td>2022</td><td>29.0</td><td>10.0</td><td>2.850</td><td></td><td></td><td>0.947</td><td>0.900</td><td>627</td><td>42</td><td></td></tr></table>