Effect of global warming on the distribution of Lucifer intermedius and L. hanseni (Decapoda) in the Changjiang estuary

We conducted an oceanographic census in 1959, 2002, and 2005 to evaluate changes in the temporo-spatial distribution and abundance of Lucifer intermedius and L. hanseni in the Changjiang estuary. In general, the abundance and frequency of occurrence (OF) for these two species were highest during the summer. We measured a significant change in the abundance and OF between years. The abundance and OF of L. intermedius increased from 3.7 individuals m−3 and 66.67%, respectively, in 1959, to 8.93 individuals m−3 and 85.19%, in 2002. In 1959, L. hanseni was only found during the summer (abundance: 0.01 individuals m−3, OF: 3.70%). However, in 2002, this species was collected during all seasons except the winter. Furthermore, abundance (0.47 individuals m−3) and OF (25.93%) were higher in 2002 than in 1959. Further increases in abundance and OF were measured during cruises during the spring of 2005. We hypothesize that global warming is responsible for the increase in abundance of L. intermedius and L. hanseni and the northward expansion of L. hanseni in the Changjiang estuary. Given our results, monitoring of both species may be useful to evaluate the effects of climate change.