This project aimed to develop and test general tools for management strategy evaluations (MSEs) for stocks that are assessed using SPiCT, SAM, seasonal SAM, and SMS. We conducted MSEs for sprat and Norway pout stocks which directly informed the advice for those stocks. Both stocks have assessment models (seasonal SAM and SMS) that account for seasonality of the fisheries and the stocks due to the short-lived, fast-maturing features of these species. Because they recruit at age 0 and because of the seasonality, standard existing software for MSEs such as FLR is not applicable. The knowledge we gained in this process will make it easier to do MSEs for sandeel in the near future.
We wrote an R package named "iamse" which can simulate stocks in a more general way than was previously possible. As needed for short-lived stocks, the package can simulate seasonality inthe fishery dynamics and stock productivity. We were able to link it to SAM and SPiCT, but not SMS and seasonal SAM. SMS is not as easy to connect with R because it has input and output spreadout over numerous files. With more time and expertise it might be possible to link with SMS, or it might be possible to make a new version of SMS in R. We determined that it would not be possibleto run seasonal SAM in an automatic way as needed in an MSE because it often requires manual tuning.
We implemented an extension to the state-space assessment model SAM to include a process model for weights (stock-weights and catch-weights) and proportion mature. It was also added to the forecst methods. We verified that it improves the models for 14 stocks. By default the new options are turned off in SAM to ensure backwards compatibility.
Funding
The project if funded by the European Maritime and Fisheries Fund and Danish Fisheries Agency and other national funds.
Research area: Fisheries Management
Research area: Ecosystem based Marine Management
Research area: Marine Living Resources