Ichthyoplankton species composition and distribution in Hangzhou Bay in summer during 20042010

In summer during 2004~2010,a total of 93 ichthyoplankton samples were collected at 15 stations in Hangzhou Bay.As results,233 eggs and 29 825 larvae were obtained.Meanwhile,a total of 34 taxa of fish larvae were found belonging to 8 orders,17 families and 26 genera.Coilia mystus was the dominant species with a percentage of 91.5% of the whole ichthyoplankton.The range of dominance was 80.0%~99.1%.Other familiar species included Periophthalmus sp.1,Liza haematocheila,Mugil cephalus,Thrissa mystax,Anchoviella commersonii,Collichthys lucidus,Benthosema pterotum,etc.Ichthyoplankton in surrounding water of Tanxu island and in the southern Hangzhou Bay was much denser compared with other areas.The main ecological groups were brackish water group,coastal group and alongshore group.Results of stepwise regression analysis with ichthyoplankton density and environmental factors showed that the correlation was significant(p0.05) between ichthyoplankton logarithm density and factors of hydrological conditions including salinity,temperature and particularly water transparency.