This seems to be correlated with natural population dynamics of those buy Ku-0059436 species in Baltic Sea ( Dippner et al., 2000, Möllmann and Köster, 2002, Renz and Hirche, 2006, Szaniawska, 1977, Szulz et al., 2012 and Wiktor and Żmijewska, 1985). Higher production rates of Acartia spp. and T. longicornis also fit to the trend observed by Möllmann and Köster (2002) and Renz et al. (2007) in the central Baltic. Although observed production rates were few times lower than those noticed by Hansen et al. (2006) than may be related to flaws in our methodology as well as long-term variability. The latter seems to be indicated by the production rates

noticed in 2007 which were much closer in value to those observed by Hansen et al. (2006). A similar dynamics of Copepod secondary production was recorded by Kang and Kang (2005) BIBF-1120 for Acartia steueri. For over 2 years of research seasonal production rate for this copepod was the highest in summer (0.47 mg/C m−2), while the lowest values were observed

in winter. Similarly to the Gulf of Gdańsk secondary production rates does not exceed 0.1 mg/C m−2. Pseudocalanus sp. is one of the key species in the Baltic Sea ( Corkett and McLaren, 1978, Renz and Hirche, 2006 and Renz et al., 2007), serving as a major food item for many commercially important fish species. Production rates observed for this species in Gulf of Gdańsk were low in comparison to that observed in Central Baltic ( Renz et al., 2007); however this was most likely connected to relatively low depth in investigated Masitinib (AB1010) area. Möllmann and Köster (2002) observed highest production rates of this species in Bornholm Basin in late spring and summer, with values in the range of 4–6 mg C m−2, which is around two to three times higher than that observed in this study. In comparison of daily mortality rates of investigated species, lowest fluctuations occur in case of Acartia spp. Throughout the study there was a visible trend of increased mortality during spring and summer. This coincides with the observations made by Möllmann and Köster (2002), which implicates that high mortality rates of Acartia spp., T. longicornis and

Pseudocalanus sp. in spring and summer may be related to clupeid fish predation ( Köster et al., 2001). For T. longicornis our results show a significant difference in mortality between different copepodite stages. In winter and autumn the highest mortality applies for stages CI/CII, and in the summer for CV. Concentrating on summer, we can compare our results of daily mortality rate with those provided by Möllmann and Köster (2002). In the summer of 2006 and 2007, the average mortality rate for CI/CII was in the range 0.10–0.25, while in Möllmann and Köster value of mortality in the years 1978–1996 ranged from 0.0 to 0.16, which may indicate a greater predation by fish on T. longicornis or deterioration of environmental conditions affecting this species in The Gulf of Gdańsk. Pseudocalanus sp.