Study of environmental and three kilka species regime shifts in the Caspian Sea

One of the major sources of impacts on marine resources comes from climate variability and regime shifts. In this context, the present study pinpoints the role of climatic and environmental parameters on the dynamic of kilka in the Caspian Sea. During the last decades, landings and stocks of the main pelagic species of kilka had been changed dramatically in the Caspian Sea. This study focuses on the last three decades of the climate regime and tries to explain the part of the changes in the recruitment (R) and spawning stock biomass (SSB) of three kilka species. Based on the statistical analysis of data series, it is found that regime changes in the global and regional environmental variables started in the mid-1995s, however, the shift of the late 1990s (1998) was more strong in the Caspian Sea. The study further reveals that the global climatic indices changes in the late 1990s are triggering the regional and local indices induced regime shifts in the late 1990s and 2000s. The study concludes that the changes in populations of fish species, especially for kilka, could be due to the regime shift.