Royal Netherlands Institute for Sea Research
Phone number
+31 (0)222 36 9577
Senior Scientist
  • Community dynamics
  • Fish ecology, Species interactions
  • Size-structured population dynamics
  • Nonlinear dynamics
  • Life-history

Dr. Anieke van Leeuwen

Senior Scientist

‘Mathematics helps to introduce ecology into fish research’

Ecologist Anieke van Leeuwen tries to understand the dynamics of fish communities by describing their entire life cycle in mathematical terms. ‘That work is relevant, amongst other things, for determining realistic fishing quotas. The mathematics behind fish ecology might sound drier than it actually is. For me, mathematics is nothing more than an instrument, just like another colleague might use a fishing net to do research, and yet another uses a microscope. By describing the eggs, larvae, young fish and adult animals, as well as their food and the reproduction of a fish species, as the X, Y and Z of a mathematical formula, I can very accurately describe how the various factors are connected to each other. And then the reality proves to be a bit less black and white than we had thought for a long time in fish research.’

Predator helps prey

‘In the Baltic Sea, I have described the relationship between cod and sprat by using such mathematical formulas. This revealed, for example, that cod helps to keep the population of their prey, sprat, healthy. If we catch too many cod, then so many young sprat remain alive that they literally get in each other’s way and too few individuals grow large enough to produce food for cod in the form of newborn sprat. Eventually, thanks to these analyses, I discovered that in a system where too many cod are fished, the system can tip over a threshold and cod will not recover easily, even when fishing stops.'

Understanding or predicting

‘Previously, we mainly focused on understanding ecological relationships in the past. In the Swimway project of the Wadden Fund, we are looking into the future, to find starting points for management of the Wadden Sea to enhance fish populations and ecosystem resilience.’

‘Ultimately, I hope that when bodies such as the International Council for the Exploration of the Sea (ICES) calculate fish stocks, they will also consider the complex relationship between the different life stages of a single species and between different species and their environment. Up until now, the fish stocks and fish quota are determined by fairly black and white bookkeeping methods. Fortunately, we are seeing the first very careful steps towards a more ecological calculation of the fish quota. We really must start by understanding biodiversity before we can effectively protect it. Mathematical models can be a very useful tool in that regard.’

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Research interests

I study the dynamics of marine ecosystems with emphasis on the roles of individual life-history, species interactions, fisheries, and parasites. Ecologically diverse, these subjects share some crucial aspects: energy is the common currency for organismal interactions and low-level processes shape high-level dynamics. I use mathematical modeling to study interactions and feedbacks, within and between species.

My research questions revolve for example around the mechanisms that lead to population collapses of Atlantic cod, how size-structure in fish populations shapes the top-down and bottom-up regulation in marine ecosystems, and how predation can influence the size-structure of host species to the benefit of parasites.

My scientific approach and expertise are focused on the conceptual and theoretical aspects of research. At the same time, I study ecological questions with direct implications for real-world systems and I rely on the insights from empirical research to stay grounded with the fundamental ecology of these systems. The most beautiful science bridges various modes of research and integrates conceptual levels.




From 2022: Senior Scientist; Royal Netherlands Institute of Sea Research (NIOZ)

From 2017: Tenure track Scientist; Royal Netherlands Institute of Sea Research (NIOZ)

From 2016: Writing in Science and Engineering Fellow Instructor for the Princeton Writing Center; Princeton University 

From 2015: Postdoctoral Research Associate; Social-ecological complexity and adaptation in exploited marine systems; Princeton University 

2013 – 2015: Postdoctoral Research Associate; Trophic dynamics of Trematode parasites in size-structured networks; Princeton University



Please find my complete list of NIOZ-publications at the bottom of this webpage or on Google Scholar. You can download all my publications on ReserearchGate.


Professional education

2008-2012: Ph.D. Theoretical Ecology; The Cod delusion – Implications of life history complexity for predator-prey community dynamics; University of Amsterdam

2008: M.Sc. Biological Sciences with distinction; How Cod shapes its world; University of Amsterdam

2007: B.Sc. General Biology; Empirical evidence for apparent competition; University of Amsterdam


Awards and Prizes

2014: Netherlands Ecological Research Network publication award 1st prize Predators with multiple ontogenetic niche shifts have limited potential for population growth and top-down control of their prey (van Leeuwen et. al. 2013. The American Naturalist)

2009: University of Amsterdam Master thesis award 2nd prize How Cod shapes its world (van Leeuwen et al. 2008. Journal of Sea Research)


Teaching and supervision

From 2016: Princeton Writing Program: Writing in Science and Engineering – Six-week graduate student and postdoc workshop resulting in full manuscript drafts. Instructor & Editor

From 2015: Prison Teaching Initiative: Algebra and Statistics for incarcerated students. Instructor

From 2010: BSc thesis advising and supervision, 2 students, University of Amsterdam Senior thesis advising and supervision, 2 students, Princeton University

2013- 2014: Parasitology (undergraduate level, instructed at the Smithsonian Tropical Research Institute, Gamboa, Panama) Princeton University. Guest lecturer

2014: Tropical Field Ecology (graduate level, instructed at Mpala research center, Laikipia, Kenya) Princeton University. Assistant

2007- 2012: Theoretical Biology (BSc. level) University of Amsterdam. Teaching assistant (TA)

2010- 2011: Introduction to Ecology & Evolution (MSc. level) University of Amsterdam. TA

2007–2011: Quantitative Population Ecology (BSc. level) University of Amsterdam. TA

Conference contributions

2015: Main organizer of Organized Oral Session titled: Parasites in trophic networks: complex life cycles, coinfection dynamics, and community structure. ESA 100th Annual Meeting, Baltimore MD

2014: Convener of the session: Intraspecific body-size dynamics on ecological and evolutionary time scales. Netherlands Annual Ecology Meeting (NAEM), Lunteren, The Netherlands

Linked news

Wednesday 13 March 2024
Significant impact of global warming on biodiversity in European seas
Over the past 40 years, the Atlantic Ocean has experienced a tropicalization of its communities, with an increase in the abundance of warmer-water species, while the Mediterranean and the Baltic Sea, where warming has been more rapid, have seen a…
Monday 27 November 2023
A warmer Wadden Sea: tough choices for fish
For cold-blooded species, temperature determines their activity and metabolism: if it is warm enough, they become active and if it gets too cold, they remain still. But apart from temperature, fish respond to more environmental factors: for example,…
Friday 30 June 2023
Dossier: warm sea and ocean water
Global warming dominates global news. Here, rising atmospheric temperatures are usually the common thread. But of all the extra heat trapped by our greenhouse gas emissions, only 1 per cent remains in the air. The vast majority (89 per cent)…
Monday 07 November 2022
Spectacular skate returns to North Sea
The skate is a ray that can easily reach a meter in length, up to almost three meters from head to tail. This spectacular fish is returning to the North Sea. An analysis of historical data, by NIOZ researchers Anieke van Leeuwen and Roeland Bom,…
Tuesday 07 June 2022
World Ocean Day 8th June 2022 | Thank you sea, and five challenges
June 8th is World Oceans Day: declared 30 years ago by the United Nations to draw attention to the importance of healthy oceans for a habitable planet Earth. In this short video from the Royal Netherlands Institute for Sea Research (NIOZ), we present…
Friday 19 June 2020
The North Sea’s forgotten angels
The presence of Angelsharks in the North Sea has faded from our memory. In a recent publication in Marine Biology, WWF nature conservationists and NIOZ researchers urge that we put top predators from earlier centuries back into the ‘baseline’ picture…
Friday 12 June 2020
Rare parasites found in the NIOZ fyke
On the Friday morning 12th June, Dennis Mosk and Maureen Sikkema found a thick-lipped mullet in the NIOZ fyke with a large parasite attached to it’s anal fin. They regularly find parasites on fish from the NIOZ fyke, but this type of parasite is not…
Monday 01 July 2019
Waddenfonds steunt Swimway Waddenzee
Het project "Waddentools – Swimway Waddenzee" kan dankzij een bijdrage vanuit het Waddenfonds van start gaan. Dat werd vrijdag 28 juni door het Waddenfonds bekend gemaakt. Doel van het project is om erachter te komen met welke beheermaatregelen de…

NIOZ publications

Linked projects

Anieke van Leeuwen
Project duration
1 Jan 2020 - 31 Dec 2024
New website for NIOZ

This year we are going to redesign and technically improve the NIOZ website. We would like to take your opinion as website visitor into account.

By answering 10 questions you can help us enormously! It will take you no longer than 4 minutes. You can win a NIOZ t-shirt and a book voucher to the value of EUR 25 if you fill in the questions.

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