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.

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.

Since 2019 I am coordinating SLU Water Forum which aims to gather and strenghten water research at SLU, from Source-to-Sea. 

Since 2022 I am the appointed Vice Dean for Monitoring and Assessment at the NJ-Faculty.



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.
  • Fishing in the city. Together with other researchers at SLU and Uppsala university I am involved in Formas-funded project surveying Urban fishing.  
  • Verktyg för att utforska rumsliga och temporala variationer av miljögiftskoncentrationer i Östersjöns biota – en fallstudie av kvicksilver. Together with researchers at the Swedish Mesuem of Natural History and Stockholm University I am involved in the Formas-funded project aiming at increasing our understanding on the pathways for hazardous substances to the living organisms in the Baltic Sea.


  • I am leading several projects aiming at monitoring coastal fish communites in Sweden.
  • As highlighted above my research focus on developing status assessment tools for coastal fish to support marine management in foremost the Baltic Sea.
  • Since the spring 2022 I am also appointed as the vicedean for Environmental Monitoring and Assessment at the NJ-Faculty at SLU.
  • Since more than 10-years I am chairing the HELCOM expert goup on coastal fish, HELCOM FISH PRO III.


I have co-supervised 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

50. Vivó-Pons, A., Wallin, I., Olsson, J., Ljungberg, P., Behrens, J., Lindegren, M. 2023. The devil is in the details: exploring how functionally distinct round goby is among native fish in the Baltic Sea. NeoBiota. 89:
161–186. doi: 10.3897/neobiota.89.110203 

49. Östman Ö, Hommik K, Bolund E, Heikinheimo O, Olin M, Lejk, A, Svirgsden R,Smolinski S, Olsson J. 2023. Size based indicators for assessments of ecological status of coastal fish communities. ICES J Mar Sci. 

48. Östman Ö, Sundblad G, Ljungberg P, Levin S, Blass M, Kaljuste M, Dahlin I, Svensson R, Olsson J. 2023. Catches, bycatches and stock indicators of fisheries targeting cyprinids along the Swedish Baltic Sea coast. Fisheries Research. 268, 106829. 

47. Kruze E, Avotins E, Rozenfelde L, Putnis I, Sics I, Briekmane L, Olsson J. 2023. The population development of the invasive Round Goby Neogobius melanostomus in Latvian waters of the Baltic Sea. FISHES. 8, 305.

46. Olsson J, Andersson ML, Bergström U, Arlinghaus R, Audzijonyte A, Berg S, Briekmane L, Dainys J, Dalby Ravn H, Droll J, Dziemian Ł, Fey DP, van Gemert R, Greszkiewicz M, Grochowski A, Jakubavičiūtė E, Lozys L, Lejk AM, Mustamäki N, Naddafi R, Olin M, Saks L, Skov C, Smoliński S, Svirgsden R, Tiainen J, Östman Ö. 2023. A pan Baltic assessment of temporal trends in coastal pike populations. Fisheries Research, 260, 106594.

45. Naddafi, R., Östman, Ö., Bergström L., Mustamäki N., Appelberg M., Olsson J. 2022. Improving assessments of coastal ecosystems - adjusting coastal fish indicators to variation in ambient environmental factors. Ecological Indicators. 145, 109604.

44. Olin AB, Olsson J, Eklöf JS, Eriksson BK, Kaljuste O, Briekmane L, Bergström. 2022. Increases of opportunistic species in response to ecosystem change: the case of the Baltic Sea three-spined stickleback. ICES J Mar Sci., 79:1419-1434.

43. Joosse, S, Hensle L, Boonstra WJ, Ponzelar C, Olsson J. 2021. Fishing in the city for food—a paradigmatic case of sustainability in urban blue space. npj Urban Sustainability (2021)1:41,

42. Eriksson BK, Yanos C, Bourlat S, Donadi S, Fontaine MC, Hansen JP, Jakubavičiūtė E, Kiragosyan K, Maan M, Merilä J, Austin ÅN,, Olsson J, Reiss K, Sundblad G, Bergström U, Eklöf JS. 2021. Plate phenotypes determine the distribution of three-spined stickleback in a rapidly expanding population. Ecosphere 12(6):e03561.

41. Blenckner T, Möllmann C, Lowndes JS, Griffiths JR, Campbell E, De Cervo A, Belgrano A, Boström C, Fleming V, Frazier M,  Neuenfeldt  S, Niiranen S, Nilsson A, Ojaveer H,  Olsson J,   Palmlöv CS,  Quaas  M, Rickels W,  Sobek A,  Viitasalo M,  Wikström SA Halpern BS, 2021. The Baltic Health Index (BHI): Assessing the social–ecological status of the Baltic Sea. People and Nature, 3:359-375.

40. Laurila-Pant M, Mäntyniemi S, Östman Ö, Olsson J, Uusitalo L, Lehikoinen, A. 2021. A Bayesian approach for assessing the boundary between desirable and undesirable environmental status - an example from a coastal fish indicator in the Baltic Sea. Ecological Indicators, 120, 106975.

39. Hanson N, Larsson Å, Parkkonen J, Faxneld S, Nyberg E, Bignert S, Ek H.H, Bryhn A, Olsson J, Karlson A.ML, Förlin L. 2020. Ecological changes as a plausible explanation for differences in uptake of contaminants between European perch and eelpout in a coastal area of the Baltic Sea. Environmental Toxicology and Pharmacology. 80: 103455.

38. Östman, Ö., Bergström, L., Leonardsson, K., Gårdmark, A., Casini, M., Sjöblom, Y., Haas, F., Olsson J. 2020. Analyses of structural changes in ecological time series (ASCETS). Ecological Indicators, 116, 106469.

37. Jernberg S, Nygård H, Aunins A, Lappalainen A, Heiskanen  A-S, Olsson J, Kauppila P, Korpinen S, Kostamo K, Uusitalo L. 2019.  A retrospective assessment of marine biodiversity: a critical analysis of integration and aggregation rules. Socio-Environmental Systems Modelling. Vol. 1, 2019.

36. Olsson J, Jakubavičiūtė E, Kaljuste O, Larsson N, Bergström U, Casini M, Cardinale M, Hjelm J and Byström P. 2019. The first large-scale assessment of three-spined stickleback (Gasterosteus aculeatus) biomass and spatial distribution in the Baltic Sea.  ICES J Mar Sci, 76: 1653–1665. doi:10.1093/icesjms/fsz078 

35. Olsson J. 2019. Past and Current Trends of Coastal Predatory Fish in the Baltic Sea with a Focus on Perch, Pike, and Pikeperch. FISHES. 4, 7.

34. Lehikoinen A, Olsson J, Bergström L, Bergström U, Bryhn A, Fredriksson R, Uusitalo L. 2019. Evaluating complex relationships between ecological indicators and environmental factors in the Baltic Sea: a machine learning approach. Ecological Indicators. 101: 117-125.

33. Törnroos A, Pecuchet L, Olsson J, Gårdmark  A, Blomqvist  M, Lindegren M, Bonsdorff E. 2019. Four decades of functional community change reveals gradual trends and low interlinkage across trophic groups in a large marine ecosystem. Global Change Biology. 25: 1235-1246.

32. Jakubaviciute E, de Blick Y, Dainys J, Lozys L, Olsson J. 2018. Morphological divergence of three-spined stickleback in the Baltic Sea – implications for stock identification. Fisheries Research, 204: 305-315.

31. Kraufvelin P, Pekcan-Hekim Z, Bergström U, Florin A-B, Lehikoinen A, Mattila J, Arula T, Briekmane L, Brown EJ, Celmer Z, Dainys J, Jokinen H, Kääriä P, Kallasvuo M, Lappalainen A, Lozys L, Möller P, Orio A,  Rohtla M, Saks L, Snickars M, Støttrup J, Sundblad G, Taal I, Ustups D, Verliin A, Vetemaa M, Winkler H, Wozniczka A, Olsson J. 2018. Essential coastal habitats for fish in the Baltic Sea. Estuarine, Coastal and Shelf Science. 204: 14-30.

30. Svensson F, Karlsson E, Gårdmark A, Olsson J, Adill A, Zie J, Snoeijs P, Eklöf JS. 2017. In situ warming strengthens trophic cascades in a coastal food web. Oikos. 126: 1150-1161.

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)

Larsson et al. 2023. Indikatorrapportering för “Hållbart nyttjande av fisk- och skaldjursbestånd i kust och hav”: bedömningsåret 2022. 

Heimbrand et al. 2022. Faktablad från integrerad kustfiskövervakning 2022:4
- Torhamn, södra Egentliga Östersjön, 2002–2021. 2022:4 

Heimbrand et al. 2022. Faktablad från Integrerad kustfiskövervakning 2022:3 - Kvädöfjärden, Egentliga Östersjön, 1981-2021. 

Heimbrand et al. 2022. Faktablad från Integrerad kustfiskövervakning 2022:2 - Holmöarna, Bottniska viken, 1989-2021.

Heimbrand et al. 2022. Faktablad från Integrerad kustfiskövervakning 2022:1 - Fjällbacka, Västerhavet, 1989–2021 

Wennhage, H., Naddafi, R., Mustamäki, N., Orio, A., Bergström, L., Sköld, M., Bergenius, M., Valentinsson, D. & Olsson, J. (2021). Påverkansanalys fisk – till åtgärdsprogram för havsmiljön. Aqua reports 2021:22 

Dahlin I, Levin S, Olsson J, Östman Ö. 2021. Fishing cyprinids for food: Evaluation of ecosystem effects and contaminants in cyprinid fish. Aqua reports 2021:20

Faithfull, C, Koehler, B, Bergström, U, Berkström, C., Erlandsson, M., Fetterplace, L., Karlsson, A., Olsson, J., Svanfeldt, K., Thor, P., Wikström, S.A. and L. Bergström (2021) Kunskapsunderlag för ekosystembaserad havsförvaltning i Bottenhavet. Aqua reports 2021:13 




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