Status of the Tana/Teno River salmon populations in 2024

Anon. 2025. Status of the Tana/Teno River salmon populations in 2024. Report from the Tana/Teno Monitoring and Research Group nr 1/2025. This report is the eighth status assessment of the re-established Tana/Teno Monitoring and Research Group (MRG) after the 2017 agreement between Norway and Finland. After a summary of salmon monitoring time series in Tana/Teno, we present an updated status assessment of fourteen stocks/areas of the Tana/Teno river system. All stocks were evaluated in terms of a management target defined as a 75 % probability that the spawning target has been met over the last four years. A scale of four years has been chosen to dampen the effect of annual variation on the status. Assessing the stock status is answering the question about how well a salmon stock is doing, how many salmon were left at the spawning grounds and how many should there have been. The question about how many salmon should spawn has been addressed by the defined spawning targets for the different populations (Falkegård et al. 2014). The unprecedented situation in 2021-2024, when a total moratorium of salmon fisheries was put in place both in the Teno/Tana river system and in large areas in Tanafjord and in adjacent coastal areas, meant that in contrast to the several alternative ways of estimating the spawning stock used in earlier years (Anon. 2020), only direct counts of ascending and spawning salmon were used in the assessments in 2021-2024 because of the absence of salmon catches. The map below summarizes the 2021-2024 stock status of the evaluated parts of the Tana/Teno river system. Symbol colour designates the management target, defined as probability of reaching the respective spawning targets over the last four years. The management target was classified into five groups with the following definitions: 1) Probability of reaching the spawning target over the last four years higher than 75 % and attainment higher than 140 % (dark green color in the summary map below) 2) Probability higher than 75 %, attainment lower than 140 % (light green) 3) Probability between 40 and 75 % (yellow) 4) Probability under 40 %, at least three of the four years with exploitable surplus (orange) 5) Probability under 40 %, more than one year without exploitable surplus (red) Based on the status assessment, thirteen of the fourteen evaluated areas had a management target below 40 %, and all of these areas were placed in the worst (red) status category due to no exploitable surplus in at least two of the last four years. Of the stocks with poor status, the most important thing to note is the status of the upper main headwater areas of Kárášjohka, Iešjohka and Anárjohka/Inarijoki and of the Tana/Teno main stem. These areas, which constitute 80.5 % of the total Tana/Teno spawning target, have had consistently low target attainment and low to no exploitable surplus over several years. To conclude, the situation for different salmon stocks of the Tana/Teno system in 2024 continued to show an overall negative status with exceptionally low spawning stocks and low estimates of pre-fishery abundance. The numbers of large MSW salmon were still low, in line with what was predicted for 2024. The return of 1SW salmon in Tana/Teno has been low since 2019. This situation turned significantly worse in 2024, with the overall 1SW run size being by far the lowest we have seen. This happened despite relatively good smolt numbers found in the monitoring in 2023. The low 1SW numbers in 2024 has critical implications for the return of 2SW salmon in 2025, which, given the long-term relation between 1SW one year and 2SW the year after, are now expected to be catastrophically bad. Most 2SW salmon are female, and consequently, the overall spawning stock size and resulting egg deposition in 2025 can be expected to be well below the levels from 2024. Given the critical red status category for thirteen of fourteen assessed areas (the Tana/Teno total not shown in the figure below), the biological advice, based on the recommended stock recovery procedure given in Anon (2022), is that no exploitation should take place for stocks placed in the red category until the forecast indicates the return of an exploitable surplus and status categories increase to at least orange. The table below summarizes the stock-specific target attainment and probability for enough spawners for 2024, and the average target attainment and probability for reaching the spawning target over the last 4 years (=the management target). A key task for the MRG is identifying knowledge gaps and give advice on relevant monitoring and research. The declining stock situation and apparent downward trend in mortality from smolt to adult, which was considerably more pronounced from 2023 to 2024 in Tana/Teno compared to neighbouring rivers, has led to a collapse in 1SW salmon in 2024. This collapse has possible connections to either, or both, climate change and the 2023 pink salmon trap. It is crucial that this knowledge gap is prioritized in 2025. We strongly advise prioritizing resources towards an individual-based telemetry study in 2025 with a study design that allows for gathering data on downstream smolt migration and the cost of any delays at the 2025 trap site. Another crucial question, which could be studied simultaneously, is the upstream migration of adult Atlantic salmon and the possible delays and problems the pink salmon trap may cause.