Greenhouse radiation efficiency


Improving Methods for Evaluation of Research Survey Information under consideration of Survey Fish Detection and Catch Efficiency

Promovendus mr. JR (Jorgen) Nielsen
Promotor dr. AD (Adriaan) Rijnsdorp
Organisatie Wageningen University

ma 26 januari 2015 11:00 tot 12:30

Locatie Auditorium, building number 362
Generaal Foulkesweg 1
6703 BG Wageningen


The thesis developed methods to integrate the analysis of different types of fishery independent research surveys to estimate distribution, density, abundance, migration, and population dynamic parameters of marine fish species. The thesis focus on factors and methods influencing the survey catch and detection efficiency to estimate more precise parameters to improve stock assessments, fisheries management advice, long term management evaluation, and precise marine spatial planning. Advanced statistical methods were applied and new methodology was developed for analyzing correlation in distribution and density according to space, time, size and species as well as for inter-calibration of trawl surveys. Hydroacoustic survey methods were studied to improve detection and discrimination of fish species according to fish size and orientation in the water.  This allowed for improved estimates of the distribution and density patterns of juvenile Baltic cod, which hitherto were largely unknown. More precise estimates of mortality, maturity, and growth of Norway pout were obtained from trawl survey data taking into account spatial variation.  Methods to integrate hydroacoustic, gillnet, and hydrographical research survey data to study pelagic fish migration patterns were developed and applied to Western Baltic herring. Finally, methods to analyse research survey data were reviewed focusing on data distributions, survey design and stratification, trawl survey inter-calibration and standardization, as well as estimation procedures and data processing methods, in particular focusing on survey precision and uncertainty and the factors affecting it