Ken Haste Andersen



Professor in theoretical marine ecology at AQUA, DTU. Deputy chair in the Centre for Ocean Life.


News

April 2013: New paper: Size structure, not metabolic scaling rules, determines fisheries reference points. We develop a comprehensive framework for a size-based model of an exploited fish population. The framework is based on a metabolic assumption at the level of the individual. Despite this, we show that the population-level properties, like fisheries reference points, do not obey metabolic scaling rules. The framework is general and can be used to generalise the impact of fishing across species and for making demographic and evolutionary impact assessments of fishing, particularly in data-poor situations. The model has been implemented as a javascript applet.
The fishing mortality giving the maximum yield (Fmsy) as a function of the maximum size of fish in a population (Woo) (black line). The black dots are Fmsy for selected fish stocks from official ICES assessments. The grey areas represent runs with random parameters of the model (see paper for details).

December 2012: New paper: Control of plankton seasonal succession by adaptive grazing.

March 2012: New paper: Trait diversity promotes stability of community dynamics.  In this paper we show that the dynamic solutions of the community size spectrum model are unrealistic.  We do this by comparing the community model with the same model where we have added trait diversity.  The model with trait diversity has dynamic solutions with much smaller amplitude than the community model (see below).  These results are important because they demonstrate the limitations of the community size-spectrum model.  My student, Lai Zhang, performed the technically demanding calculations behind this exercise.

Phase plot of predator biomass as a function of prey biomass for the simple community size-spectrum model (grey) and the same model where the diversity of individuals is accounted for (black).  The basic model has chaotic dynamics and very large amplitude variation whereas the model with trait diversity has regular and low amplitude oscillations.

Teaching

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 hearing more about these courses.

Research Interests

My main interest is to understand how life in the ocean is organised and how it reacts to perturbations like fishing, species removals/invasions or climate change. More specifically I work on:
 Previously I have worked with sand ripples under surface waves and barchan dunes in deserts.

Student projects:

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:
  • 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
Former students:
  • 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).

Contact information:

Ken Haste Andersen - kha@aqua.dtu.dk - +45 35 883399
National Institute of Aquatic Resources, AQUA
Technical University of Denmark
Jægersborg Allé 1
DK-2920 Charlottenlund
Denmark
Subpages (1): Publications