Diversity in life histories and genetic structure in a large population complex of wild Atlantic salmon in the River Teno, northernmost Europe

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1 Diversity in life histories and genetic structure in a large population complex of wild Atlantic salmon in the River Teno, northernmost Europe Jaakko Erkinaro Finnish Game and Fisheries Research Institute, Oulu, Finland DSRRN 213 Science Meeting January 213

2 Acknowledgements Juha-Pekka Vähä Morten Falkegård Eero Niemelä Panu Orell Maija Länsman Jorma Kuusela Matti Kylmäaho Jari Haantie Jorma Ollila Kjell-Magne Johnsen

3 Teno/Tana/Deatnu Catchment area km 2 Mean discharge 17 m 3 /s (max. 3 m 3 /s) > 12 km and >3 tributaries available for anadromous salmon Green = tributaries with predominantly 1-sea-winter salmon Black= stretches and tributaries with high % of multi-sea-winter salmon

4 Salmon fishing in the River Teno nets (weir, gill net, drift net, seine) rods (boat fishing, fly fishing) Monitoring of salmon stock diversity all fishing season (late May-end of August) all catchment (main stem, tributaries) all user groups, fishing methods 3-9 scale samples per year (age, genetics)

5 Sea age + previous spawning times Life histories of the River Teno Atlantic salmon Smolt age x X X X X x x 1S1 x X X X X 2 x 3S2 X x X X x X X 2S1 x X X X x 3 x 1S1S1 X x X X x X x 3S1 x X X X x 4 2S1S1 X x X x X X x 1S2 X X x 5 x x x 3S1S1 X X x 2S2 x x x 1S1S1S1 x x x 96 combinations!

6 Size difference within male individuals reproducing at the same time & place up to 1 fold! (3g vs. 3 g)

7 Catch, kg Atlantic salmon catch in the River Teno 25 2 Norway Finland

8 Salmon catch of the River Teno Estimated number of salmon in the catch Previous spawners 4-5 SW 3 SW 2 SW 1 SW Total catch (tonnes) Year

9 Distribution (%) of salmon from 199 year class across later spawning years Maiden salmon Previous spawners A single year class may contribute to reproduction over 12 years So what if there wasn t this diversity? Less buffer/resilience against environmental/human disturbances, less adaptation to various habitats Portfolio effect? Diversity is stabilizing ecosystems and the services they provide analogy: asset diversity & stability of financial portfolios

10 Baiss Leva Nili Luft Genetic structure of the River Teno salmon stock complex 3+ baseline populations Geaimm e Aku Karigas Noiaid at Iskuras Vuoma Anar Skietsha m Univ Turku

11 Genetics of the River Teno salmon - Substantial genetic differences between populations - Mean pairwise F ST.1 (max.21) (Vähä et al. 27) - Large populations more diverse, small more diverged - Life history matters: % of MSW females linked to gen variation large females important in maintaining biodiversity (Vähä et al. 27 Mol. Ecol) - Temporal stability in population complex structure - 197s > 8s > 9s > 2s ( Vähä et al. 28 Evol. Appl.) - Run timing of salmon to the Teno is populationspecific - Life history matters: 1SW males from populations with high % of MSW females migrate later (Vähä et al. 211 Evol. Appl.) Photo: Panu Orell Applicable management implications >

12 Coast Main stem Fjord, estuary Tributary Accumulated population-specific exploitation

13 Exploitation in different fisheries and spawning escapement in two River Teno tributaries (% of pre-fishery abundance) Coastal 19 % Máskejohka Main stem 11 % Spawning stock 41 % Máskejohka 29 % Iésjohka

14 Mixed-stock exploitation in the River Teno main stem fishery; Multi-sea-winter-salmon catch in 28 1 % 9 % 8 % 7 % 6 % 5 % 4 % 3 % 2 % 1 % % Week Iesjohka (N) Karasjohka (N) Anarjohka (N/F) Akujoki (F) Valljohka (N) Baisjohka (N) Levajohka (N) Kuoppilasjoki (F) Utsjoki (F) Vetsijoki (F) Laksjohka (N) Polmak (N/F) Luovttejohka (N) Maskejohka (N) Tana main stem Univ Turku

15 Early season exploitation of populations and life-history groups: Driftnet catch in lower part of the River Teno main stem 25 YläTeno Vetsi Valjoki Karasjohka Utsjoki and Iesjohka salmon are Tsarsjoki MSW TanaBru salmon catch important contributors to the maiden Lots Pulmanki of previously spawned salmon in the Outakoski driftnet catches Maske Luft Leva Laksjoki Kuoppilas Kevo Many small grilse populations well represented (e.g. Pulmanki, Kevo, Tsars, Valjoki) where PS salmon are the ~only large females Critical exploitation on the largest females in multpile populations of small tributaries? Keskiteno Karasjoki Inarijoki Previous spawners Maiden MSW PS maiden PS maiden Tana Teno Iesjoki Baisjoki Akujoki Univ Turku

16 25 2 Negative trend for 3-4SW-salmon 1 in the 5 River 5 Teno salmon catches SW 1 1 Estimated number of salmon in the catch SW Females 2 SW 2 Males

17 Positive trend for previous spawners; 1-2SW? Major change in fishing regulations Previous spawners SW 1 1 Estimated number of salmon in the catch SW Females 2 SW 2 Males

18 Fish length, cm Selectivity of marine drift nets Coastal drift nets in Norway mostly 65 7 mm knot to knot Especially selective for mid-size salmon, 6 8 cm (TL) Ban in Norway in 1989 Abundance of PS, 2SW, large grilse increased in the Teno Size of 1SW increased (more large grilse escaped), 2SW decreased (more small 2SW escaped) 9 Gillnet SW 6 1 SW Weir

19 Selective fishing on River Utsjoki (tributary) salmon in the River Teno main stem? Sea age distribution of salmon in: Video at the Utsjoki river mouth Teno main stem catch of salmon assigned to R. Utsjoki origin Video monitoring Catch in the main stem Video station at the Utsjoki river mouth Lower main stem fishing area Video monitoring Catch in the main stem River Utsjoki catchment

20 Challenge How to manage the mixed-stock fishery and diverse salmon stock complex in the Teno system?

21 Run timing of 1SW salmon in the lowest part of the River Teno main stem Univ Turku Small tributaries Large tributaries Upper main stem Large tributaries Lower main stem Vähä et al. 211 Evol. Appl.

22 Run timing of 1-3 SW salmon originating from the rivers Karasjohka and Iesjohka, captured in the lowest part of the Teno main stem Univ Turku 3SW Karasjohka 3SW Iesjohka 2SW Karasjohka 2SW Iesjohka 1SW Karasjohka 1SW Iesjohka Lower main stem fishing area R. Iesjohka The RIVER TENO Days starting from 2 May = 1. R. Karasjohka

23 Modern genetic methods, rigorous catch data, and monitoring programmes collection of stock status data and spatial and temporal information on population-specific exploitation in mixed-stock fisheries tailoring of population- and life-history group-specific management actions, depending on the status of different populations

24 Negotiations on a new bilateral Finnish Norwegian fishery agreement for the River Teno, started in 212 Management will be flexible, adaptive, knowledge (science)-based and population-specific Decision structure (NASCO): Criteria for stock status (conservation limits) for all populations Monitoring the stock status: spawning stock size and diversity Pre-agreed management actions, effective automatically when criteria are not met

25 Concluding remarks Large variety of life histories and genetic groups in the Teno salmon Diversity improves resilience and economy (!?) worth safeguarding Management and conservation should be population- and life historyspecific Challenges! Opportunities! Photo: Panu Orell