Ecological and evolutionary interactions between farmed and wild Atlantic salmon

Transcription

1 Ecological and evolutionary interactions between farmed and wild Atlantic salmon Kjetil Hindar, research director Sten Karlsson, Ola Diserud, Peder Fiske, Geir Bolstad NINA, Trondheim

2 Outline Farmed and wild Atlantic salmon Escaped farmed salmon in rivers Genetic introgression Methods development A study in 125 rivers shows widespread introgression Consequences of introgression Controlled experiments in a few rivers Ecological studies in many rivers Mechanisms of interaction Conclusions

3 Farmed Atlantic salmon escapes/yr since escaped during 2015 Wild PFA Norway: /yr Differs from wild Morphology Scale patterns Selected for efficient captive production 2x growth after 5 gen. Genetically different Phylogenetic history Genetic markers Ecological traits

4 Escaped farmed salmon in rivers (%) Prosent oppdrettslaks Dots = autumn exp catches, unweighted averages c. 40 rivers/yr Triangles = summer sport fishing, unweighted averages c. 75 rivers

5 Genetic introgression: find genetic markers that distinguish farmed from wild Wild salmon N Tanaelva Altaelva-81,-82, Saltdalselva-77, Namsen Gaula-89, Driva-77, Surna Rauma-74, , Lærdalselva-77,-78, Vossoelva-77, Suldalslågen-79, Figgjoelva Numedalslågen Total 553 Farmed salmon N AG98 48 AG99 89 AG00 58 AG MOWI04 20 MOWI05 20 MOWI08 20 MOWI09 20 SB04 47 SB05 47 SB06 48 SB07 48 Total SNPs tested: Set of 60 diagnostic between wild and farmed Karlsson S et al Molecular Ecology Resources 11(Suppl. 1)

6 Genetic introgression: calculate proportional wild ancestry for 1 by 1 ind. Wild Finnmark Farmed Coord. 2 Wild not Finnmark Coord. 1 PCoA plot of pairwise F ST estimates between historical samples from 39 Atlantic salmon populations and 13 farmed strains populations. Grey diamonds=populations in a hybrid zone between Barents (Finnmark) and Atlantic (not Finnmark) populations Karlsson S et al Ecology and Evolution 4

7 Government request: National Quality Norm for Salmon (from Norwegian Biodiversity Act) Characterize status with respect to genetic effects of farmed salmon on wild salmon No change observed Weak changes indicated Moderate changes shown Large changes shown Appendix for Norwegian Scientific Committee for Wild Salmon Management (VRL) Temarapport 4 >20,000 wild salmon examined (farmed escapes excluded); 15,000 of them were adults having completed a life-cycle in the wild See Data compiled from Glover et al BMC Genetics 14 and Karlsson et al ICES J Marine Sci 73

8 Genetic status: 125 rivers on a map GREEN No genetic change observed (e.g. River Tana) YELLOW Weak genetic changes indicated (Namsen) ORANGE Moderate genetic changes shown (4-10% introgression; Alta) RED Large genetic changes shown (>10% introgression; Vosso, Lærdal, Stryn, Målselv)

9 Higher introgression in rivers with more escaped farmed salmon notable variation between rivers; red dots = county averages Correlation for 77 populations = Estimated introgression Karlsson et al Mean annual percentage

10 What does it mean? Controlled experiments in Burrishoole Ireland, and Imsa and Guddalselva Norway Ecological change (growth and life history) Lower survival Reduced fitness Lower population productivity (Imsa: 30% reduction of smolts relative to Stock-Recruit) Fleming et al Proc. R. Soc. 267 McGinnity et al Proc R. Soc. 270 Skaala et al Can. J. Fish. Aquat. Sci. 69

11 Consequences in natural populations Genetic diversity among populations is reduced (Glover et al PLoS ONE 7) Genetic introgression 0 47% (Glover et al BMC Genetics 14); similar range in Karlsson et al., 2016 ICES J Marine Sci 73) Life-history and size-at-age change with increased introgression (Geir Bolstad et al. 2017, Nature Ecology and Evolution 1, 0124 ) Effect dependent on phylogenetic origin of wild population (vs origin of farmed strains) Effect dependent on ecotype of wild population («smallsized» vs «large-sized»)

12 Functional genes SNPs in 1500 salmon from 57 populations and three lineages A single gene explains almost 40% of variation in seaage at maturity May have implications for salmon management and farmed salmon breeding programmes Barson et al Nature 528 Ayllon et al PLoS Genetics 11

13 Mechanisms Why do we find reduced egg-to-smolt survival in wild salmon competing with farmed offspring, when farmed egg-to-smolt survival is low? w w-f f-w w w-f f-w Sundt-Hansen et al Journal of Fish Biology 86

14 Conclusion 1/3 of 125 Atlantic salmon populations in show moderate to large genetic changes Highest introgression in intensely farmed regions Important life-history traits change by introgression Pro-active management is necessary Closed technology no escapees Sterile (triploid or otherwise) farmed salmon Tagging (recognize) farmed salmon Research for co-existence

15 Papers Karlsson, S., Moen, T., Lien, S., Glover, K.A., and Hindar, K Generic genetic differences between farmed and wild Atlantic salmon identified from a 7K SNP-chip. Molecular Ecology Resources, 11 (Suppl. 1): Karlsson, S., Diserud, O. H., Moen, T., and Hindar, K A standardized method for quantifying unidirectional genetic introgression. Ecology and Evolution, 4(16): Karlsson, S., Diserud, O. H., Fiske, P., and Hindar, K Widespread genetic introgression of escaped farmed Atlantic salmon in wild salmon populations. ICES Journal of Marine Science 73: Bolstad, G.H., Hindar, K., Robertsen, G., Jonsson, B., Sægrov, H., Diserud, O.H., Fiske, P., Jensen, A.J., Urdal, K., Næsje, T.F., Barlaup, B.T., Florø-Larsen, B., Lo, H., Niemelä, E., & Karlsson, S Gene flow from domesticated escapes alters the life history of wild Atlantic salmon. Nature Ecology & Evolution, 1: DOI: /s (published 10 th April; after meeting)

16 - and a recent review

17 Foto på side 1: P. Jordhøy, J. Thomassen, E. B. Thorstad, A. Staverløkk, T. Aarvak, B. Løken/Samfoto