This was a Strategic Institute Program in collaboration with Institute for Marine Research (IMR). The main goal of this strategic programme was to develop methods and standardised procedures that enable estimation of absolute abundance of fish stocks. NR's responsibility was to provide estimates of the total uncertainty.

The goal of NR's work was to estimate stock abundance and composition from an integrative analysis of acoustic data and trawl data obtained in the research surveys. The data gathering process is modelled statistically. Models are on different scales in space and time. At the small scale of the individual trawl haul or acoustic survey leg. At the large scale, all data from one survey are integrated to give estimates for the surveyed area.

We have developed a method to quantify the uncertainty of abundance and age-specific abundance estimates of Norwegian spring-spawning herring, accounting for the combined effect of several error sources.