The objective is to apply existing Baltic Sea monitoring data and identify their adequacy for establishing time series of whole sea-basin of:
- Mass and number of landings of fish by species and year.
- Mass and number of discards and bycatch (of fish, mammals, and seabirds) by species and year.
The time-series are as long as possible for each considered species. The final aim is to provide an overall picture of the trends over the years of landing, discard and by-catch by species.
Relevant data for the target parameters (listed below) were gathered from EMODnet, ICES, HELCOM, STECF, as well as national authorities and relevant (inter)national projects with an open data access.
The specific data required for this challenge include:
- Time series of annual landings in weight by species from each country fishing in the Baltic Sea,.
- Time series of annual landings in numbers, by species from each country fishing in the Baltic Sea. To derive this requires data on mean weight of fish, and preferably data on size/age structure of landings of each species.
- Time series of annual discards in weight from each country fishing in the Baltic Sea, for relevant species.
- Time series of annual discards in numbers from each country fishing in the Baltic Sea, for relevant species. This requires data on mean weight of fish of a species in discards and preferably data on size/age structure of the discards of a species.
- Data on estimated bycatch of mammals (seals, harbour porpoises) and seabirds
- All time series for landings should extend as far back as possible and include the period before the Data Collection Regulation came into force. From 2002 estimates on discards are collected regularly, some discard data are available prior to 2002.
Furthermore, the outcome of the literature survey (work package 1) was used; e.g. to inform what the key data sets are and definitions of terminology.
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