Initiative to improve mackerel assessment via tagging data (39080)

The assessment of NEA mackerel had issues with this assessment related to the data. The most problematic data issue for NEA mackerel is the unknown amount of unreported catches in the past. The single index was available only every third year, which caused substantial revision of the perceived stock each time a new survey point was incorporated. Furthermore, the uncertainty in the stock estimate in the terminal assessment year increased as one moved away from the last available egg survey point.

This project extended the state-space assessment model SAM (developed at DTU-Aqua) to use tag-recapture information. This was done in order to correctly propagate uncertainties associated with the tag-recapture data. In preparation of the benchmark two meetings were held with the objective to analyze the information given by the tagging data and write the code for the model extension.

The model was extended and accepted as the primary model for NEA mackerel at the following benchmark assessment meeting.

This project was coordinated by Danish Pelagic Producers Organisation and funded by the Danish Ministry of Food, Agriculture and Fisheries and the European Fisheries Fund (EFF).

Research area: Marine Living Resources