Long-term population data of marine invaders are rarely collected
although it provides fundamental knowledge of the invasion dynamics that
is important for evaluating the impacts, interactions and range
expansion of the invader and for management purposes. During a 6-year
monitoring period, we studied the dynamics and population demographic
characteristics of the newly introduced mud crab Rhithropanopeus harrisii. The overall abundance of R. harrisii
appeared to follow the boom and bust pattern with a rapid initial
abundance increase and subsequent decline. The recruitment and growth of
juveniles were correlated with the temperature during the larval period
indicating that the increase in water temperature caused by climate
change could have a positive effect on the recruitment and have
potentially facilitated the establishment of R. harrisii
in the northern Baltic Sea. The changes in the survival of reproductive
females influence most the growth rate of the studied population.
Hence, native predators feeding on benthic fauna such as fish could
regulate the population growth of R. harrisii
in the study area by reducing female survival. Although the population
size seems to be stabilized at the monitoring locations, R. harrisii
continues to expand its distribution range, and the rapid initial
population increase is likely occurring at newly invaded sites.