day−1) is a true recruitment rate to stage i. The ratio of the numbers of individuals in two consecutive stages is expressed as a function of the mortality and the stage durations: equation(4) vivi+1=exp(θαi)−11−exp(−θαi+1) This equation is not applicable for adults and CV stages, therefore for those stages a different equation was used: equation(5) vq−1vq=exp(θαq−1)−1where index q represents the adults and q − 1 is a juvenile stage recruiting to the adult stage. For analyses of zooplankton dynamics, each stage

duration should be computed independently (αi denotes an estimate of αi). Furthermore, to apply Eqs. (3) and (4) in mortality estimation, estimates of the ratio of the numbers of individuals in two consecutive stages Cabozantinib in vitro (ri = ni/ni+1) (ni – estimate of vi) are needed ( Aksnes and Ohman, 1996). In mortality estimates it is assumed that two successive stages are taken impartially and are under the same influence of transport processes during these stages. This lead to a mortality estimate designed in the form of the following equations ( Aksnes and Ohman, 1996): equation(6) [exp(mαi)−1][1−exp(−mαi+1)]=ri (for two juvenile stages) equation(7) m=ln(rq−1+1)αq−1 (for juvenile and adult stage)where ni is an estimate of abundance vi, m is an estimate

of θ (day−1), index q is the adult stage and q − 1 is a juvenile stage recruiting to the adult stage. Results of final Copepoda mortality estimates should be the average of several m estimates from multiple sampling. Observed

biomass values ranged from 0.01 mg C m−3 to a maximum of almost 13 mg C m−3. Acartia spp. reached the highest biomass values in both summers ( Fig. 2), although Target Selective Inhibitor Library in 2007 it was almost three times higher Ketotifen than a year earlier. The variation of biomass between stations was very low, with the exception of So4 station in summer 2007 when visibly higher biomass was noticed, although Mann–Whitney U test showed statistically significant (p < 0.05) differences in copepod biomass between series of corresponding months and seasons of both investigated years in regard to each investigated species and between sampling stations. Biomass temporal variability of T. longicornis was very similar to Acartia spp., but with lower values; highest biomass was also observed in summer (highest in 2007). Although in spatial distribution T. longicornis reached higher biomass values at deeper stations (J23, SO4, SO3). For Pseudocalanus sp. maximum biomass was only 0.8 mg C m−3, and there were no noticeable patterns in its variability depending on water temperature, although this species’ biomass was clearly concentrated at the deepest stations (J23 and SO4). Biomass of both Acartia spp. and T. longicornis were positively correlated with water temperature (correlation coefficient r = 0.8; p < 0.05) (except for shallowest stations M2 and So1 for T. longicornis), correlation was calculated for mean values for each month, as well as for each sampling station separately.