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Institute of

FI Fisheries Ecology


Fish Diseases in the North Sea and Baltic Sea

© Maike v. Klinkowstöm

Monitoring of abundance, regional distribution, temporal changes and causes of diseases and parasites in ecologically and economically important marine fish stocks, including histopathological changes

Healthy like a fish in water? In order to find out whether this saying is correct, we monitor the occurrence of diseases in a range of fish species from the North Sea and Baltic Sea during our research cruises onboard RV "Walther Herwig III".

Background and Objective

Diseases and finess parameters in marine fishes reflect the impact of anthropogenic (e.g., exposure to hazadous substances ) and natural stressors on the health status of fish. They are, thus, important indicators of the quality status of the marine environment. In the framework of the integrated monitoring programme of the Thünen Institute of Fisheries Ecology, we record and assess regional patterns and temporal trends in the prevalence of infectious and non-infectious diseases (including parasites and histopthological changes). We can identify problem areas with sigificantly increased disease prevalences and, in the context of, e.g., contaminant effects, deduce a requirement of measures.


How prevalent and spatially distributed are diseases and parasites in ecologically and economically important fish species of the North Sea and Baltic Sea? This we monitor by means of fish catches during our annual research vessel surveys. We record externally visible diseases and parasites (flatfish and roundfish) as well as pathological liver anomalies (flatfish). The programme is part of the integrated monitoring programme of the Thünen Institute of Fisheries Ecology on contaminants and their biological effects in marine fishes. The programme is standardised at the international level; the methods applied are according to ICES recommendations and OSPAR guidelines for biological effects monitoring. 

Data and Methods

Data generated within the monitoring programme are submitted to the ICES Environmental Database on an annual basis and are analysed by ICES expert groups. They have regularly been used for the preparation of national and international reports on the status of the marine environment. 

Our Research Questions

Are there regional patterns and trends in the prevalence of fish diseases in the North Sea, Baltic Sea and in reference areas?

Can causes of regional patterns and trends be identified?

Which methods are appropriate for the assessment of results?

Is there a relationship between regional patterns and trends in fish diseases  and the dynamics of fish stocks (recruitment, reproduction, mortality)?

Preliminary Results

ICES Working Groups and Committees analyse and assess the results of the running studies; the results have been utilized for national and international status reports, such as BLMP Status Reports on the quality of the marine environment of the North Sea and Baltic Sea, OSPAR Quality Status Report 2010, HELCOM integrated assessments of hazardous substances.

Links and Downloads

Funding Body

  • Federal Ministry of Food und Agriculture (BMEL)
    (national, öffentlich)


Permanent task 1.1987 - 12.2023

More Information

Project status: ongoing


  1. 0

    Lang T, Feist SW, Stentiford GD, Bignell JP, Vethaak AD, Wosniok W (2017) Diseases of dab (Limanda limanda): Analysis and assessment of data on externally visible diseases, macroscopic liver neoplasms and liver histopathology in the North Sea, Baltic Sea and off Iceland . Mar Environ Res 124:61-69, DOI:10.1016/j.marenvres.2015.12.009

  2. 1

    Lang T, Kruse R, Haarich M, Wosniok W (2017) Mercury species in dab (Limanda limanda) from the North Sea, Baltic Sea and Icelandic waters in relation to host-spacific variables. Mar Environ Res 124:32-40, DOI:10.1016/j.marenvres.2016.03.001

  3. 2

    Rummel C, Löder MGJ, Fricke NF, Lang T, Griebeler E-M, Janke M, Gerdts G (2016) Plastic ingestion by pelagic and demersal fish from the North Sea and Baltic Sea. Mar Pollut Bull 102(1):134-141, DOI:10.1016/j.marpolbul.2015.11.043

  4. 3

    Lehtonen KK, Sundelin B, Lang T, Strand J (2014) Development of tools for integrated monitoring and assessment of hazardous substances and their biological effects in the Baltic Sea. Ambio 43(1):69-81, DOI:10.1007/s13280-013-0478-3

  5. 4

    Grütjen F, Lang T, Feist SW, Bruno D, Noguera PA, Wosniok W (2013) Hyperpigmentation in North Sea dab Limanda limanda. I. Spatial and temporal patterns and host effects. Diseases Aquat Organ 103(1):9-24, doi:10.3354/dao02554

  6. 5

    Noguera PA, Feist SW, Bateman K, Lang T, Grütjen F, Bruno D (2013) Hyperpigmentation in North Sea dab Limanda limanda. II. Macroscopic and microscopic characteristics and pathogen screening. Diseases Aquat Organ 103:25-34, doi:10.3354/dao02553

  7. 6

    Lang T, Feist SW, Wosniok W, Vethaak AD (2012) Background document: externally visible fish diseases, macroscopic liver neoplasms, and liver histopathology. ICES Coop Res Rep 315:84-103

  8. 7

    Dabrowska H, Ostaszewska T, Kamaszewski M, Antoniak A, Napora-Rutkowski L, Kopko O, Lang T, Fricke NF, Lehtonen KK (2012) Histopathological, histomorphometrical, and immunohistochemical biomarkers in flounder (Platichthys flesus) from the southern Baltic Sea . Ecotoxicol Environ Safety 78:14-21, DOI:10.1016/j.ecoenv.2011.10.025

  9. 8

    Fricke NF, Stentiford GD, Feist SW, Lang T (2012) Liver histopathology in Baltic eelpout (Zoarces viviparus) – A baseline study for use in marine environmental monitoring. Mar Environ Res 82:1-14, DOI:10.1016/j.marenvres.2012.08.012

  10. 9

    Vethaak AD, Lang T, Davies IM (2012) Technical annex: sampling and analysis for integrated chemical and biological effects monitoring in fish and shellfish. ICES Coop Res Rep 315:182-190

  11. 10

    KorpinenS, Laamanen M, Andersen JH, Asplund L, Berger U, Bignert A, Boalt E, Broeg K, Brzozowska A, Cato I, Durkin M, Garnaga G, Gustavson K, Haarich M, Hedlund B, Köngäs P, Lang T, Larsen MM, Lehtonen KK, Murray C, et al (2010) Hazardous substances in the Baltic Sea : an integrated thematic assessment of hazardous substances in the Baltic Sea. Helsinki: Helsinki Commission, Baltic Sea Environ Proc 120B

  12. 11

    Rybakovas A, Barsiene J, Lang T (2009) Environmental genotoxicity and cytotoxicity in the offshore zones of the Baltic and the North Seas. Mar Environ Res 68(5):246-256, DOI:10.1016/j.marenvres.2009.06.014

  13. 12

    Malmström C, Konn M, Bogovski S, Lang T, Lönnström LG, Bylund G (2009) Screening of hydrophobic DNA adducts in flounder (Platichthys flesus) from the Baltic Sea. Chemosphere 77(11):1514-1519, DOI:10.1016/j.chemosphere.2009.09.055

  14. 13

    Baumgart F, Lang T, Feist SW, Bruno D, Noguera PA, Wosniok W (2008) Hyperpigmentation in North Sea dab (Limanda limanda) : spatial and temporal patterns, host effects and possible causes. Copenhagen: ICES, 23 p

  15. 14

    Lang T, Baumgart F, Bruno D, Feist SW, Noguera PA (2008) Progress report on studies carried out on hyperpigmentation in common dab (Limanda limanda). ICES WGPDMO Rep 2008:77-83

  16. 15

    Lang T, Wosniok W, Barsiene J, Broeg K, Kopecka J, Parkkonen J (2006) Liver histopathology in Baltic flounder (Platichthys flesus) as indicator of biological effects of contaminants. Mar Pollut Bull 53(8-9):488-496, DOI:10.1016/j.marpolbul.2005.11.008

  17. 16

    Feist SW, Lang T, Stentiford GD, Köhler A (2004) Biological effects of contaminants: use of liver pathology of the European flatfish dab (Limanda limanda L.) and flounder (Plathichthys flesus L.) for monitoring. Copenhagen: ICES, 42 pp p, ICES Techn Mar Environ Sci

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