Ken Haste Andersen

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


"Some things still need to be said about the world". Pliny the Elder, Naturalis Historia

News

December 2013: New paper The consequences of balanced harvesting of fish communities. How shall we manage fisheries within an ecosystem approach to fisheries?  A recently proposed solution is to make a "balanced" harvesting of ecosystem components. Balanced harvesting implies that small individuals should be fished harder than large individuals. We make an assessment of balanced harvesting using the size-spectrum modelling concept. We find that balanced harvesting can produce as much biomass yield as current fishing patterns, and it may even do so at a lower risk of compromising other ecosystem components. The price to pay is that the catch is comprised mainly of small individuals. Balanced harvesting can therefore be viewed an attempt to maximise the yield from a forage fishery at the expense of yield from the consumer fishery.

October 2013: Updated the single-species size-spectrum simulator. Now with possibility to simulate "balanced fishing".

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).

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 any of these courses.

Research Interests

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 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

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