Fish Biology Group
National Institute of Aquatic Recourses
Technical University of Denmark

Dr. Jonna Tomkiewicz
Phone: +45 35883408

National Institute of Aquatic Recourses
Technical University of Denmark
Charlottenlund Castle, Jaegersborg Allé 1,
Dk-2920 Charlottenlund (Denmark)

Group description
The Fish Biology Group is part of the Marine Ecology Section at the National Institute of Aquatic Recourses, Technical University of Denmark ( The group includes 3 professors/research scientists, 1 PostDoc, 2 PhDs, 2 technicians, and several MSc and BSc students. The group focuses on individual-based studies related to reproduction, growth, and behaviour in fishes. Fish reproductive and nutritional physiology, eco-physiology, morphology and molecular genetics are key research areas. Ecological field studies and statistically designed experiments are integrated activities.

Main lines of research
Specific research foci of the group include:
 Growth and developmental characteristics throughout ontogeny
 Nutritional physiology, nutritional requirements, and energetics
 Gametogenesis, reproductive traits and physiology, life history theory, and fitness
 Gamete quality, offspring viability, and developmental competence
 Eco-physiology, requirements and constraints, internal and external drivers
Integrated interdisciplinary work includes the project: Captive European eel reproduction: broodstock nutrition, induced maturation and egg quality, fertilisation and embryonic development competence and larval culture (

National Institute of Aquatic Recourses:
Research Area Individual-based Studies:
Education Programs in Aquatic Science and Technology:
PRO-EEL Project. Reproduction of European Eel: Towards a Self-sustained Aquaculture.

Relevant publications

1. Bucholtz, R.H.; Tomkiewicz, J., Nyengaard, J. R., Andersen, J.B. 2013 Oogenesis, fecundity and condition of Baltic herring (Clupea harengus L.): A stereological study. Fisheries Research, 145, 100-113.
2. Butts, I.A.E., Babiak, I., Ciereszko, A., Litvak, M.K., Słowińska, M., Soler, C., & Trippel, E.A. 2011. Semen characteristics and their ability to predict sperm cryopreservation potential of Atlantic cod, Gadus morhua L. Theriogenology 75, 1290-1300.
3. Butts, I.A.E., Feindel, N., Neil, S., Kovács, É., Urbányi, B., & Trippel, E.A. 2011. Cryopreservation of Atlantic cod (Gadus morhua) sperm in large volume straws: Applications for commercial production and gene banking. Aquaculture Research 42, 1714-1722.
4. Butts, I.A.E., Johnson, K., Wilson, C., & Pitcher, T.E. 2012. Ovarian fluid enhances sperm velocity based on relatedness in lake trout, Salvelinus namaycush. Theriogenology 78, 2105-2109.
5. Butts, I.A.E., Mokdad, A., Alavi, S.M.H., & Pitcher, T.E. 2013. Physiological functions of osmolality and calcium ions on the initiation of sperm motility and swimming performance in redside dace, Clinostomus elongates. Comparative Biochemistry and Physiology – Part A: Molecular & Integrative Physiology, 166, 147-157.
6. Butts, I.A.E., Mokdad, A., Trippel, E.A., & Pitcher, T.E. 2013. Development of a sperm cryopreservation protocol for redside dace, Clinostomus elongatus: implications for genome resource banking. Transactions of the American Fisheries Society 142, 671-680.
7. Butts, I.A.E., Politis, S.N., Sørensen, S.R., & Tomkiewicz, Gadus morhua J. 2014. Standardization of fertilization protocols for the European eel. Aquaculture. Accepted. AQUA-S-13-01778.
8. Butts, I.A.E., Roustaian, P., & Litvak, M.K. 2012. Fertilization strategies for winter flounder: effects of spermatozoa density and the duration of gamete receptivity. Aquatic Biology 16, 115-124.
9. Butts, I.A.E., Trippel, E.A., Ciereszko, A., Soler, C., Słowińska, M., Alavi, S.M.H., Litvak, M.K., & Babiak, I. 2011. Seminal plasma biochemistry and spermatozoa characteristics of Atlantic cod (L.) of wild and cultivated origin. Comparative Biochemistry and Physiology – Part A: Molecular & Integrative Physiology 159, 16-24.
10. Lowerre-Barbieri, S.K.; Brown-Peterson, N.J.; Murua, H., Tomkiewicz, J., Wyanski, D.M., Saborido-Rey, F. 2011. Emerging issues and methodological advances in fisheries reproductive biology. Marine and Coastal Fisheries 3(1), 32-51.
11. Pasquier, J., Lafont, A.G., Jeng, S.R., Morini, M., Dirks, R.P., van den Thillart, G., Tomkiewicz, J., Chang, C.F., Rousseau, K., Dufour, S., 2012. Multiple kisspeptin receptors in early osteichthyans provide new insights into the evolution of this receptor family. PLoS ONE 7(11): e48931.
12. Røjbek, M., Jacobsen, C., Tomkiewicz, J., Støttrup, J.G. 2012. Linking lipid dynamics with the reproductive cycle in Baltic cod Gadus morhua. Marine Ecology Progress Series, 471, 215-234.
13. Sørensen, S. R., Gallego, V., Pérez, L., Butts, I.E.A.; Tomkiewicz, J., Asturiano, J. 2013. Evaluation of methods to determine sperm density for the European eel, Anguilla anguilla: Reproduction in Domestic Animals, 48 (6), 936-944.
14. Støttrup, J.G., Jacobsen, C., Tomkiewicz, J., Jarlbæk, H. 2013. Modification of essential fatty acid composition in broodstock of cultured European eel Anguilla anguilla L. Aquaculture Nutrition, 19(2), pp 172–185
15. Tomkiewicz, J., Kofoed, T.M.N. and Pedersen, J.S. 2011. Assessment of testes development during induced spermatogenesis in European eel Anguilla anguilla. Marine and Coastal Fisheries: Dynamics, Management and Ecosystem Science 3(1), 106-118.