Resultat från övervakningen av kustfisk: östra Singö (Egentliga Östersjön) 2025

This report presents the results of the coastal survey fishing conducted in Singö, with the aim of describing the fish community in this Helcom Marine Protected Area. The survey was conducted using Nordic coastal multi-mesh gillnets, and the species composition of the catch, as well as fish size and abundance, were analyzed. Environmental variables were also recorded in connection with the survey. Age determination of perch was conducted after completion of the survey. The survey area is in Norrtälje Municipality in Stockholm County, and the coastal water type is outer coastal waters of Uppland. With its diversity of habitats and bottom types, the area provides spawning and nursery grounds for many common Baltic coastal fish species, such as perch, cyprinids, and whitefish. The area is influenced by recreational boat traffic, and the use of nearshore areas is extensive. The results show that values for environmental variables, as well as diversity indices and mean trophic level, fall within the expected range compared with nearby survey fishing areas. The fish community is both numerically and species-rich, reflecting the diversity of habitats within the survey area. The total catch is higher than in nearby survey areas. Notably, high numbers of cyprinids— particularly roach—were caught, as well as a high proportion of perch. The perch population in Singö displays a healthy size and age structure, although one-year-old were small. A large proportion of the catch consisted of individuals that are not sampled representatively by the gear and are therefore excluded from calculations. This possibly indicating good recruitment conditions in the area.