The Institute for Biodiversity and Ecosystem Dynamics (IBED) has a PhD position as part of the research program 'Paradigm for New Dynamic Ocean Resource Assessments and exploitation' (PANDORA), which is funded by the European Union under its Horizon 2020 program. The aim of the PhD project is to explore the potential consequences of density dependent individual growth for current management of marine fish stocks and develop strategies for adaptation of management to take these effects into account. The objective is to deliver concrete recommendations for when and how management of recovered and recovering fish stocks should take into account density dependent individual growth. Furthermore, the consequences of density-dependent growth under increasingly size-selective fishery will be investigated, which is the objective of the landing obligation. The objective of this last study is to explore if and when the landing obligation potentially reduces the productivity of the fishery, for which there are indications from modelling work.
These questions will be addressed focusing on two target fish stocks for which recent stock recovery has coincided with reduced individual growth, North-east Atlantic Mackerel (Scomber Scombrus; Teunis & Burns, 2015) and North Sea plaice (Pleuronectes platessa; T. van Kooten, unpublished). These fish are economically important stocks, but for very different fisheries. Plaice in the North Sea is a prime target species of various bottom trawling fleets, while mackerel is an important target for large pelagic trawlers. Furthermore, these fish are ecologically very different. Mackerel is a widely distributed schooling pelagic zooplankton- and fish-eater, while plaice is a non-schooling, demersal benthivorous flatfish with a strong attachment to shallow sandy seafloors.
The dynamics of these stocks will be analyzed using physiologically structured population models (PSPMs) of these species. The core of such PSPMs is a model of individual feeding, growth and mortality given the state (e.g. size, age) of the individual and the environment (e.g. food availability, temperature). In such models, the population dynamics emerge by keeping track of the change in the distribution of states of individuals over time. Because the models are individual-based, density-dependent growth reduction occurs naturally, as low food abundance primarily affects food intake of individuals, and density-dependent mortality occurs only as a secondary effect, when food shortage leads to starvation of individuals. Model predictions will be confronted with experimental and empirical data from the literature or available through collaborations with other research groups.
We offer a position for 38 hours a week in an exciting, dynamic and international research environment, starting 1 July 2018. The full-time appointment will be on a temporary basis for a maximum period of four years (18 months plus a further 30 months after a positive evaluation) and should lead to a dissertation (PhD thesis). An educational plan will be drafted that includes attendance of courses and (international) meetings. You are also expected to assist in teaching of undergraduates. The full-time gross monthly salary varies between €2,222 (first year) and € 2,840 (fourth year) gross per month (salary scale P). The Collective Labour Agreement for Dutch Universities is applicable. The annual salary will be increased by 8 % holiday allowance and 8.3 % end-of-year bonus.
Please add vacancy number 18-161 in the subject field.
Please combine these materials into a single PDF file.