“Counting the uncountable” is the fundamental challenge in fish stock assessment. To meet this challenge, Christoffer Moesgaard Albertsen has evaluated and developed state-space models in this PhD study. On 9 February, he will defend his thesis.
State-space models are a natural framework for analysing time series that cannot be observed directly or without error. This is the case for both fisheries stock assessments and movement data from marine animals.
In fisheries stock assessments, the aim is to estimate the size of a fish population; however, the number of fish cannot be measured directly. Instead, the number of fish caught from the population and samples on a small fraction of the population can be used. In marine animal movement, accurate position systems such as GPS cannot be used because they do not emit signals under water. Instead, inaccurate alternatives must be used which gives observations with large errors.
Both assessment and individual animal movement models are important for management and conservation of marine animals. Therefore, models should be developed to be operational for management while handling the complicated data structures and adequately evaluating uncertainties in the models and data.
Recent developments in computational statistics have made the use of general statespace models feasible for analysing data used for management and conservation. Models that previously required hours to fit can now be fitted in seconds. During his PhD study, Christoffer Moesgaard Albertsen, DTU Aqua has implemented models for fisheries stock assessment and individual animal movement using these recent developments. The PhD study both evaluated the use of the new methods in different settings and developed new models to improve the basis for management and conservation of marine animals.
About the defense
Friday 9 February 2018, Christoffer Moesgaard Albertsen will defend his PhD thesis "State-Space Modelling in Marine Science" at DTU. The defence takes place at 1 p.m. in building 303A, auditorium 41 at DTU’s Campus in Lyngby.
Supervisors
- Principal supervisor: Senior Researcher Anders Nielsen, DTU Aqua
- Co supervisor: Associate Professor Uffe Høgsbro Thygesen, DTU Compute
Examiners
- Professor Ken Haste Andersen, DTU Aqua
- Assistant Professor Noel Cadigan, Memorial University, Canada
- Vice-chair of Advisory Committee and PhD Carmen Fernandez, ICES
Chairperson at defence
- Senior Researcher Martin Lindegren, DTU Aqua