February 2019: A recent paper in science have shown that fish reproductive output scales faster than proportional with female weight. This data analysis is timely, relevant, and solid. The results challenge the common fisheries management assumption that reproductive output is proportional to weight. However, in a recent comment in the Canadian Journal of Fisheries and Aquatic Sciences we show that the implications of the result are much less dramatic than they are made to be. First, the graphic presentation created a distorted picture between the hypergeometric and the classic isometric description (see figure below). Second, their example for cod shows that current practice makes an error of 149%. By properly accounting for fish demography we show that the error is maximally on the order of 10%, and in most other fish stocks likely much less. Fish reproductive output may increase faster than proportionally with size. However, it does not matter much for the population-level reproductive output.
See archive for older news.
I am currently involved in the courses:
- 25303 Mathematical biology
- 25304 Differential equations in biology
- 25314 Computational Marine Ecological Modelling
- 25803 Ocean Life Meeting Series
Send me a mail if you are interested in any of these courses.
I want to understand how life in the ocean is organised, why marine organisms look and act the way they do, and how marine ecosystems react to perturbations like fishing, species removals/invasions or climate change. More specifically I work on:
- Trait-based models of life in the ocean. See http://www.oceanlifecentre.dk
- Size-structured models of marine ecosystems. See the community calculator and the single-species calculator.
- Fisheries induced evolution. See the evolutionary calculator.
Previously I have worked with sand ripples under surface waves and barchan dunes in deserts.
I have a number of possible student projects available for students related to the impact of fishing and climate change on marine and fresh water ecosystems. The projects ranges from applied projects on specific ecosystems to abstract theoretical topics. Send me an email if you are interested in learning more.
Students and post docs:
- Camila Maria Serra Pompei (PhD student)
- Rob van Gemert (PhD student)
- Daniel van Denderen (post doc)
- Trondúr Kragesteen (PhD student)
- Subhendu Chakraborty (post doc)
- Kasia Kenitz (post doc)
- Nis Sand Jacobsen, Ph.D. student. With Henrik Gislason.
- Alexandros Kokkalis, Ph.D. student. With Uffe Thygesen and Anders Nielsen.
- Julie Sainmont, Ph.D. student. Main supervisor: Andy Visser.
- Karin Olsson, Ph.D. student. Main supervisor: Henrik Gislason
- Christina Frisk, Ph.D. student. Co-supervised by Gerd Kraus.
- Nuria Calduch Verdiel, Ph.D. student. With James Vaupel, Max Planck Institute for Demographic Research, Rostock; and Brian MacKenzie. Thesis: Protecting the larger fish: an ecological, economical and evolutionary analysis using a demographic model.
- Lai Zhang, Ph.D. student. Thesis: Mathematical model of ecology and evolution
- Martin Hartvig (aka Martin Pedersen), Ph.D. student. Main supervisor: Per Lundberg, Lund University. Thesis: Food web ecology.
- Matthieu Gerard, under-graduate student: "Turing structure in a size-structured ecosystem model". Together with Uffe H. Thygesen and Michael Pedersen (MAT, DTU).
Ken Haste Andersen - email@example.com - +45 35 883399
National Institute of Aquatic Resources, AQUA
Technical University of Denmark
DK-2800 Kgs. Lyngby