Roles of fishing and climate change in long-term fish species succession and population dynamics in the outer Beibu Gulf,South China Sea

A prevailing,controversial hypothesis is that fishing pressure has played a greater role than climatic and environmental drivers,in changing fish species succession and biomass fluctuation in the South China Sea(SCS).Based on otter trawl survey data from 1959 to 2010 in the outer Beibu Gulf(OBG),northern SCS,large seasonal and interannual variation is reported for fish species composition,the proportional abundances of dominant taxa,and fish biomass.Generalized additive models are developed to quantify relationships between fish biomass and the external factors of fishing pressure and climate change.Fishing pressure proved to be the main driver of sharp declines in demersal fish stocks,with high-value species being replaced by low-value ones over time.Abrupt decreases in fish biomass during the years of 1993 and 1998 correspond to El Nino events,with climate change possibly the main driver of proportional representation of pelagic species in fisheries trawl catch.The need to differentiate impacts of fishing and environmental drivers on fish species with different life history strategies is stressed to better understand fish community dynamics.

Taxonomical notes on the family Ptilocodiidae (Anthomedusae) from the central and southern of South China Sea, with a new genus and a new species

This study reviews the Ptilocodiidae from South China Sea, including three species. The diagnoses of the family and each genus are provided. A new genus, Tregouboviopsis Guo, Xu ＆ Huang, gen. nov. is erected, based on the monotypy, Tregouboviopsis perradialis （Xu, Huang ＆ Du, 2012） comb. nov., which is transferred from the genus Tregoubovia. A free eumedusoid of Hydrichthella ocellata Xu, Huang ＆ Wang, sp. nov. is described in the present paper. A key to known genera of family Ptilocodiidae is presented. All type specimens are deposited in the South China Sea Fisheries Research Institute, Chinese Academy of Fishery Science.

Taxonomic notes on Anthomedusae(Cnidaria) from the south-central South China Sea Ⅲ:Family Pandeidae

The present paper reviews all 14 genera and 46 species belonging to the family Pandeidae from the China seas. Two new species, Leuckartiara ruberiverruca Xu, Guo & Du, sp. nov. and Merga longicosta Xu, Huang & Wang, sp. nov., from the south-central South China Sea, are described and illustrated. Keys to the known genera of family Pandeidae in the China seas and to all known species of the genus Merga are provided. Other data are briefly summarized to the list of species presented in the family Pandeidae in the China seas. The type species were deposited at the South China Sea Fisheries Research Institute, Chinese Academy of Fishery Science.