Annual and seasonal dynamics of fish in the brackish-water Matsalu Bay, Estonia

• Published in: Ecology of freshwater fish Vol. 15; no. 2; pp. 211 - 220
• Main Authors: Vetemaa, M., Eschbaum, R., Verliin, A., Albert, A., Eero, M., Lillemägi, R., Pihlak, M., Saat, T.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.06.2006
• Subjects: Blicca bjoerkna; brackish-water bay; Clupea harengus membras; Esox lucius; Estonia; estuary; fish community composition; Matsalu Bay; Osmerus eperlanus; Perca fluviatilis; Platichthys flesus; Rutilus rutilus; Sander lucioperca; Scardinius erythrophthalmus; temporal variations; Zoarces viviparus; ANE, Estonia, Laanemaa Cty., Matsalu Bay; Estonia
• ISSN: 0906-6691; 1600-0633
• DOI: 10.1111/j.1600-0633.2006.00134.x

–  Matsalu Bay in the Väinameri (West‐Estonian Archipelago Sea) is a relatively shallow but large bay. It is the only real delta estuary in the northern Baltic Sea. The fish fauna is strongly dominated by freshwater species such as perch Perca fluviatilis, roach Rutilus rutilus, white bream Blicca bjoerkna and rudd Scardinius erythrophthalmus. The study presents CPUE data describing annual and seasonal variations in the species composition, abundance and spatial distribution, based on 1 year of monthly samplings from August 2001 to August 2002 and routine coastal monitoring (in late July–early August) between 1994 and 2003. The bay can be divided into three rather distinct parts. The fish fauna of the inner part (salinity 0–2 p.p.t.) is different from two open parts and resembles that of freshwater lakes. In the openmost part (salinity usually 4–6 p.p.t.) some marine species, such as herring Clupea harengus membras, flounder Platichthys flesus and eelpout Zoarces viviparus may seasonally be abundant. Species composition and abundance of most species varies seasonally and interannually. Only the abundance of few species such as pike Esox lucius and pikeperch Stizostedion lucioperca was not impacted by seasonality. The most dynamic period in the bay is spring, when several species (some of them very rare in summer, such as herring and smelt Osmerus eperlanus) enter the bay for spawning.