Orio, Alessandro
- Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
Research article2017Peer reviewed
Orio, Alessandro; Florin, Ann-Britt; Bergström, Ulf; Šics, Ivo; Baranova, Tatjana; Casini, Michele
Standardized indices of abundance and size-based indicators are of extreme importance for monitoring fish population status. The main objectives of the current study were to (i) combine and standardize recently performed trawl survey with historical ones, (ii) explore and discuss the trends in abundance, and (iii) the trends in maximum length (Lmax) for cod (Gadus morhua) and flounder (Platichthys flesus) stocks in the Baltic Sea. Standardization of catch per unit of effort (CPUE) from trawl surveys from 1978 to 2014 to swept area per unit of time was conducted using information on trawling speed and horizontal opening of the trawls. CPUE data for cod and flounder stocks were modelled using generalized additive models (GAMs) in a delta modelling approach framework, while the Lmax data were modelled using ordinary GAMs. The CPUE time series of the Eastern Baltic cod stock closely resembles the spawning stock biomass trend from analytical stock assessment. The results obtained furnish evidence of the cod spill-over from Subdivisions (SD) 25-28 to SD 24. The decline of Lmax in recent years was evident for both species in all the stocks analysed indicating that the demersal fish community is becoming progressively dominated by small individuals. It is concluded that the standardization of long time series of fisheries-independent data constitutes a powerful tool that could help improve our knowledge on the dynamics of fished populations, thus promoting a long-term sustainable use of these marine resources
ICES Journal of Marine Science
2017, Volume: 74, number: 5, pages: 1322-1333
Coastal and sea areas
Biodiversity
SDG13 Climate action
SDG14 Life below water
Ecology
Fish and Aquacultural Science
DOI: https://doi.org/10.1093/icesjms/fsx005
https://res.slu.se/id/publ/80425