Causes of trends in abundance of mesopredators in the Kattegat Sea

• Main Author: Rudnicki, Karla
• Format: Other/Unknown Material
• Language: English
• Published: SLU/Dept. Of Aquatic Resources 2018
• Subjects: shore crab; atlantic cod; mesopredator; Vendelsöarna; temperature; Ringhals; nuclear power plant; Kattegat; Gadus morhua
• Online Access: https://stud.epsilon.slu.se/14025/

It has come to attention that there is a mesopredator release effect present in the Kattegat Sea (northern Europe, between Sweden and Denmark). The areas in focus here are Ringhals, a nuclear power plant zone, and Vendelsöarna, a undisturbed reference area. Mesopredator abundances like the Carcinus maenas (European Shore Crab) have increased over the years; while there have been a noticeable decreased population of Gadus morhua (Atlantic Cod) and a sea temperature increase since the 1970s. The aim of this research in the Kattegat Sea is to analyze the potential causes for increasing abundance of mesopredators that could cause cascading effects and alter the ecosystem itself. Since 1976, data has been collected in the Kattegat Sea region where uni- and multivariate analysis, which can examine the idea that there is a correlation between diminished population of the Gadus morhua, (Atlantic Cod) and temperature rise with mesopredator increasing distributions. Results suggest abundances of mesopredatory fish and crab were highest in areas where there were favourable habitat attributes, eg., in terms of increased temperature. Significant results stating the relationship between increased mesopredator’s abundance and Atlantic Cod deceased abundance. Smaller population of the piscivore Atlantic Cod advocates a cascading process. Adjacent areas like the Baltic Sea, have and are also experiencing these effects and results can pose particular challenges for the ecosystem.