Jens Olsson

Jens Olsson
Researcher in marine ecology and coastal fish dynamics


Research focus

  • Ecosystem state and development
  • Coastal fish ecology, community dynamics, trophic interactions and status assessments
  • Population genetics in fish

My primary research interests are in the coastal ecosystems of the Baltic Sea. I primarily work with assessing ecosystem status and investigate important causes for ecosystem change and development, especially in relation to climate, exploitation and eutrophication. Focus is devoted to coastal fish communities, especially so coastal predatory fish species as perch and pike. I am mainly using time-series analyses and multivariate statistics to assess these issues. Currently I am heavily involved in work of HELCOM in relation to Marine Strategy Framework (MSFD) and Baltic Sea Action Plan (BSAP) related issues for coastal fish, both in Sweden and in the Baltic Sea region.


Current projects

  • Indicator development and status assessments for coastal fish communities in the Baltic. This work is carried out in close cooperation with scientists around the Baltic (within HELCOM). The outcome of this work will be used in the implementation of the BSAP and MSFD.
  • “Status assessment of the MSFD in the Baltic Sea – the coastal fish example”. In this project (funded by the Swedish EPA) we assess the relationship between coastal fish indicators and pressure variables. The project also includes studies on the use of commercial catch data for indicator development and status assessments of coastal fish in the Baltic, and procedures for aggregating status assessments across indicators and regions
  • The role and status of coastal predatory fish species. Here we assess the role of coastal predatory fish in the coastal ecosystem with emphasis on their interactions with mesopredatory fish as three-spine sticklebacks. To enhance our knowledge on how to manage coastal predatory fish, we are currently running a project where we analyze the contribution of freshwater tributaries as recruitment areas for coastal perch using otolith micro-chemistry analyses. We also assess the causes behind increasing stickleback populations in the Baltic.
  • State and development of coastal ecosystems around the Baltic. Together with researchers in the ICES working group WGIAB (Working Group on Integrated Assessments of the Baltic Sea) I am currently involved in the first large scale study assessing the state and development of coastal ecosystems in the Baltic.
  • Population genetics of coastal fish. Here emphasis is devoted to perch, pike, whitefish and pikeperch. We are analyzing the genetic variation of these species along the Swedish coast using microsatellites


I co-supervise PhD-student Egle Jakubaviciute, Nature Research Centre (Vilnius, Lithuania) on her project Small fish- big challenges: Role of three-spined stickleback in the Baltic Sea.

Publikationer i urval

Peer-reviewed papers

30. Svensson F, Karlsson E, Gårdmark A, Olsson J, Adill A, Zie J, Snoeijs P, Eklöf JS. In press. In situ warming strengthens trophic cascades in a coastal food web. Oikos. 10.1111/oik.03773

29. Griffiths JR, Kadin M, Nascimento FJA, Tamelander T, Törnroos A, Bonaglia S, Bonsdorff E, Brüchert V, Gårdmark A, Järnström M, Kotta J, Lindegren M, Nordström MC, Norkko A, Olsson J, Weigel B, Žydelis R,  Blenckner T, Niiranen S, Winder M. 2017. The importance of benthic-pelagic coupling for marine ecosystem functioning in a changing world. Global Change Biology. 23:2179-2196

28. Jakubaviciute, E., Casini, M., Lozys, L. Olsson, J. 2017. Seasonal dynamics in the diet of pelagic fish species in the south-western Baltic Proper. ICES J Mar Sci. 74: 750-758.

27. Östman, Ö., Lingman, A., Bergström, L. & Olsson, J. 2017. Temporal development and spatial scale of coastal fish indicators in reference sites in coastal ecosystems: hydroclimate and anthropogenic drivers. Journal of Applied Ecology. 54: 557-566.

26. Wennerström, L., Olsson, J., Ryman, N. & Laikre, N. 2017. Temporally stable, weak genetic structuring in brackish water northern pike (Esox lucius) in the Baltic Sea indicates a contrasting divergence pattern relative to freshwater populations. Canadian Journal of Fisheries and Aquatic Sciences. 74: 562-571.

25. Östman, Ö., Olsson, J., Dannewitz, J., Palm, S & Florin, A-B. 2017. Inferring spatial structure from population genetics and spatial synchrony in population growth of Baltic Sea fishes: implications for management. Fish and Fisheries. 18: 324-339.

24. Bergström L., Bergström, U., Olsson J., Carstensen, J. 2016. Coastal fish indicators response to natural and anthropogenic drivers - variability at temporal and different spatial scales Long term changes in the status of coastal fish in the Baltic Sea. Estuarine, Coastal and Shelf Science 183: 62-72.

23. Östman, Ö., Eklöf, J., Eriksson, B. K., Olsson, J., Moksnes, P. O., & Bergström, U. 2016. Top‐down control as important as nutrient enrichment for eutrophication effects in North Atlantic coastal ecosystems. Journal of Applied Ecology. 53:1138-1147

22. Bergström L, Heikinheimo O, Svirgsden R, Kruze E, Lozys L, Lappalainen A, Saks L, Minde A, Dainys J,  Jakubaviciute E, Ådjers K, Olsson J. 2016. Long term changes in the status of coastal fish in the Baltic Sea. Estuarine, Coastal and Shelf Science, 169: 74-84

21. Bergström, U., Olsson, J., Casini, M., Eriksson, B.K., Fredriksson, R., Wennhage, H., and Appelberg, M. 2015. Stickleback increase in the Baltic Sea - a thorny issue for coastal predatory fish. Estuarine, Coastal and Shelf Science. 163: 134-142.

20. Olsson J, Tomczak MT, Ojaveer H, Gårdmark, Arno Pollumae, Muller-Karulis B, Ustups D, Dinesen GE, Peltonen H, Putnis I, Szymanek L, Simm M, Heikinheimo O, Gasyukov P, Axe P and Bergström L. 2015. Temporal development of coastal ecosystems in the Baltic Sea over the past two decades. ICES Journal of Marine Science. 79: 2539-2548.

19. Ozerov M.Yu., Himberg M., Aykanat T., Sendek D.S., Hägerstrand H., Verliin A., Krause T., Olsson J., Primmer C.R., and Vasemägi A. 2015. Divergent selection on gill-raker number within and between whitefish (Coregonus lavaretus) ecotypes in the Baltic Sea basin. Journal of Evolutionary Biology. 28: 1170–1183

18. Byström, P., Bergström, U., Hjälten, A., Ståhl, S., Jonsson, D., & Olsson, J. 2015. Declining coastal piscivore populations in the Baltic Sea: Where and when do sticklebacks matter?. AMBIO 44, 462-471

17. Svanbäck, R.,Quevedo, M., Olsson J. and Eklöv, P. 2015. Individuals in food webs: the relationships between trophic position, omnivory and among‑individual diet variation. Oecologia, 178:103–114

16. Bryhn, AC., Ragnarsson, H. and Olsson, J. 2013. Modelling the biomass of functional groups of fish in an archipelago bay of the Baltic Sea. Ecological Modelling, 269: 86-97.

15. Olsson, J., Bergström, L and Gårdmark, A.  2013. Top-down regulation, climate and multi-decadal changes in coastal zoobenthos communities in the Baltic Sea. PlosOne, 10.1371/journal.pone.0064767.

14. Olsson, J., Bergström, L and Gårdmark, A. 2012. Abiotic drivers of coastal fish community change during four decades in the Baltic Sea. ICES J Mar Sci., 69: 961–970.

13. Olsson, J., Mo, K., Florin, A-B., Aho, T., and Ryman, N. 2012. Genetic structure of whitefish (Coregonus maraena) in the Baltic Sea. Estuarine, Coastal and Shelf Science, 97: 104-113.

12. Olsson, J., Mo, K., Florin, A-B., Aho, T., and Ryman, N. 2011. Genetic population structure of perch, Perca fluviatilis L, along the Swedish coast of the Baltic Sea. Journal of Fish Biology, 79: 122–137.

11. Eriksson, B. K., Sieben, K., Eklöf, J., Ljunggren, L., Olsson, J., Casini, M., and Bergström, U. 2011. Effects of altered offshore food webs on coastal ecosystems emphasizes the need for cross-ecosystem management. Ambio, 40:786-797.

10.  Vrede, T., Drakare, S., Eklöv, P., Hein, A., Liess, A., Olsson, J., Persson, J., Quevedo, M., Stabo, H.R. and Svanbäck, R. 2011. Ecological stoichiometry of Eurasian perch – intraspecific variation due to size, habitat and diet. Oikos 120: 886–896.

9.   Bergek, S & Olsson, J. 2009. Spatiotemporal analysis shows stable genetic differentiation and barriers to dispersal in the Eurasian perch (Perca fluviatilis L.). Evolutionary Ecology and Research. 11: 827-840.

8.  Olsson, J., Quevedo, M., Colson, C. & Svanbäck, R. 2007. Gut length plasticity in perch - into the bowels of resource polymorphisms. Biological Journal of the Linnean Society, 90: 517-523. 

7.  Olsson, J., Svanbäck, R. & Eklöv, P. 2007. Effects of habitat type and resource level on behavioural and morphological plasticity in Eurasian perch. Oecologia, 152: 48-56.

6.  Olsson, J., Svanbäck, R. & Eklöv, P. 2006. Growth rate constrain morphological divergence when driven by competition. Oikos, 115: 15-22.

5.  Liess, A., Olsson, J., Quevedo, M., Eklöv, P. & Hillebrand, H. 2006. Food web complexity affects stoichiometric and trophic interactions. Oikos, 114: 117-125.

4.  Quevedo, M. & Olsson, J. 2006. The effect of small-scale resource origin on trophic position estimates in Eurasian perch (Perca fluviatilis L.). Journal of Fish Biology, 69: 141-150.

3.  Olsson, J. & Eklöv, P. 2005. Habitat structure, prey type and morphological reversibility: factors influencing phenotypic plasticity in perch. Evolutionary Ecology and Research, 7: 1109-1123.

2.  Kolm, N., Hoffman, E. A., Olsson, J., Berglund, A. & Jones, A. G. 2005. Extreme group stability and homing behaviour does not result in kin group structures in a coral reef fish. Behavioral Ecology, 16: 521-527.

1. Kolm, N. & Olsson, J. 2002. Differential investment in the Banggai cardinalfish: can females adjust egg size close to egg maturation to match the attractiveness of a new partner? Journal of Fish Biology, 63(Supplement A): 144-151.

Reports (most recent)

Kraufvelin, P. 2016. Essential fish habitats (EFH) - conclusions from a workshop on the importance, mapping, monitoring, threats and conservation of coastal EFH in the Baltic Sea. TemaNord 2016:539.

Hansson N et al. 2016. Bottendjuren påverkar fiskens hälsa. HAVET 2015/2016.

Olsson, J et al. 2016. Kustekosystem förändras i takt med övergödningen. HAVET 2015/2016.

Olsson, J. et al. 2015. Abundance of coastal fish key functional groups. HELCOM core indicator report.

Olsson, J. et al. 2015. Abundance of coastal fish key species. HELCOM core indicator report.

Olsson, J., Lingman, A & Bergström, U. 2015. Using catch statistics from the small scale coastal Baltic fishery for status assessment of coastal fish. Aqua reports 2015:13. Sveriges lantbruksuniversitet, Öregrund. 65 s.

Olsson, J., Ragnarsson-Stabo, H & Bergström U. 2015. Rätt åtgärder för kustfisken. Västerhavet, s. 9

Förlin et al. 2014. Vad orsakar den försämrade hälsan hos kustfisk? – Fokus Kvädöfjärden.

HAVET 2014

Hjelm J, Bergström U, Olsson J & Sahlin U. 2014. Framtidens Abborr- och gäddbestånd

längs kusten – förvaltning på lokal skala. HAVET 2014

Adill, A., Mo, K., Sevastik, S., Olsson, J., Bergström, L. 2013. Biologisk recipientkontroll vid

Forsmarks kärnkraftverk - Sammanfattande resultat av undersökningar fram till år 2012.Aqua reports 2013:19. 69 s.

Fredriksson R, Bergström U, och Olsson J. 2013. Riktlinjer för uppföljning av fiskevårdsåtgärder i kustmynnande våtmarker med fokus på gädda. Aqua reports 2013:7, 52 s.     

Olsson et al. 2013. Temporal development of baltic coastal fish communities and key species. HELCOM Baltic Sea Environment Fact Sheet 2013.

Olsson et al. 2013. Abundances of key species. HELCOM CORE indicator of biodiversity.

Olsson et al. 2013. Abundances of key functional groups. HELCOM CORE indicator of biodiversity.

Olsson, J. & Andersson, J. 2012. Övervakar vi kallvattenarter längs våra kuster? HAVET. 2012.

HELCOM. 2012. Indicator-based assessment of coastal fish community status in the Baltic Sea 2005-2009. BSEP 131.



Forskare FLK vid Institutionen för akvatiska resurser; Ekosystemanalys
Telefon: +46104784144
Institutionen för akvatiska resurser (SLU Aqua)
Box 7018
75007 Uppsala
Besöksadress: Almas Allé 5, Uppsala