Positive impact from fishing industry to stock assessment modelling

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It is a rather common view that deeper involvement of fishing industry into stock assessment and regulation procedures should require (and may lead to) significant simplification of scientific approaches, models and methodology. Such a simplification is considered to be important in order to allow science and managers to use common notions, more understandable for non-scientific world. Fortunately it is not always the case. Situation with stock assessment of some important species in North-East Atlantic may serve as a good example of the inverse process. For several years in Norwegian spring spawning herring stock assessment two different approaches were used. One of them (SeaStar model) was based on classic likelihood functions what insured proper mutual weighting of signals from all available sources of information incorporated into the model. The second one (ISVPA model) stressed the point of robustness of analysis and included a number of features aimed at consistent assessment using real (that is usually noisy) data which noise might be in fact very far from any classic distribution. Often these two approaches gave very different perceptions of the current state of the stock. These two approaches were discussed many times at forums with participation of fishing industry representatives, such as the Coastal States and NEAFC meetings. These forums made a number of requests to ICES to clarify which approach was better. Unfortunately all attempts to make choice failed. Finally, forced by fishing industry, it was recommended to elaborate a new joint model which would include best properties of the two above mentioned approaches. That is, fishing industry in fact put forward a very challenging scientific problem: to merge robustness, a non-classic branch of statistics, and classic statistics in terms of likelihoods, and to apply it to stock assessment modelling. Possible approach to such a merging which is planned to be investigated in frames of join Norwegian-Russian project is discussed.