ABSTRACT: Climate-induced shifts in zooplankton communities influence the survival and recruitment of commercially important fishes worldwide by altering the prey field up to severe food limitation. Due to recruitment failure of the Western Baltic herring stock over the last decade, we investigated the role of zooplankton and potential environmental drivers of early life stage survival in a major nearshore nursery area in the Western Baltic Sea. The seasonal synchrony between predator and prey structures annual secondary production. However, studying the cause-and-effect relations is challenging, as many monitoring programs are static in time and limited to a short period every year. We analysed weekly data from 2008 to 2020, including zooplankton density and community composition together with herring larvae survival. Larval herring productivity has been the lowest in recent years, particularly since 2014 with a record low in 2020. The annual mean total zooplankton density decreased drastically, the largest drop occurring between 2012 and 2013, declining by approximately 84%. This decrease was predominantly seen in small organisms, namely copepod nauplii, bivalve veligers, and rotifers. The total density of these mayor prey organisms for early herring life stages was positively correlated with the larval herring survival index. In turn, the decrease in the zooplankton taxa density was most likely induced by changes in the phytoplankton phenology expressed by earlier seasonal chlorophyll-a peaks. Using these high-resolution time series, we provide a potential mechanism of cascading climate change effects on the survival of young herring in the Western Baltic Sea.