Faktablad – Resultat från övervakningen av kustfisk – Kvädöfjärden (Egentliga Östersjön) 1989‒2022
Authors: Svahn Emma 
Published: March 2024

Coastal fish monitoring in the autumn has been conducted in Kvädöfjärden using the gear net series since 1989. The fishing methodology was revised in 2018 and resulted in only one night of fishing per station in contrast to six consecutive nights. Only the first night of fishing over all years has hence been included in the analysis in this report. A survey with Nordic coastal multimesh gillnets was performed for the first time in autumn the same year as the revision and has been executed annually since then. The methodologies are not fully comparable, and has thus been analysed separately in this report. The fish community is described using a set of indicators. Out of the environmental factors measured during monitoring, the water temperature has fluctuated over the years but without any directional trend. There is a decreasing trend in secchi depth in the short time series using Nordic coastal multimesh gillnets but no such trend is seen in the longer time series using the net series. In total, 20 species was caught in the survey using net series and 19 species in the Nordic coastal multimesh gillnet survey. Some species are caught using both gear types but some are unique to the respective method. The results show that there are no trends over time in the coastal fish community regarding the indicators total catch, abundance of mesopredators, abundance of piscivores, abundance of large fish, the number of species caught, diversity index and the mean trophic level of the monitoring catch. Some species in the catches (cod, whiting and burbot) are classified as vulnerable (VU) in the Swedish Red List of species 2020 by the Swedish Species Information Centre at the Swedish University of Agriculture. Vimba bream that also occurs in the catches is classified as near threatened (NT). The most common species in the survey with net series were roach and perch, but in the past few years, ruffe made up a substantial proportion of the catches. Herring is dominating the catch in the surveys with Nordic coastal multimesh gillnets, but roach and perch also constitutes a large proportion of the total catch. European smelt is the only species with an increasing trend over time while perch, white bream, pike and European flounder all have decreasing trends in the net series survey. In the survey with Nordic coastal multimesh gillnets, herring and sprat showed increasing trends over time. The catch of large fish over 30 cm was in general small and mostly comprised of whitefish in both surveys. In the net series survey, roach was also a substantial part of the large fish. European flounder had condition index over the threshold value for good condition in Kvädöfjärden and no trend over time was observed for the index. In conclusion, it can be noted that the coastal fish community in Kvädöfjärden has been relatively stable during the assessed time series, with a few exceptions. In the long time series, European smelt has increased over time and perch, white bream, pike, and European flounder have decreased over time. In the survey with the gear Nordic coastal multimesh gillnets with a considerably shorter time series, sprat and herring showed increasing trends. It can also be noted that whilst there are similarities in catches and indicators between the two fishing gears, the differences in the methodologies is also a factor that most likely can explain a large part of the dissimilarities in results between the gears.