||This study collected zooplankton and hydrographic data in the Taiwan Strait (TS) using the cruises of “Fishery Research I” from January 2005 to October 2006, to investigate the seasonal and spatial distribution of planktonic pteropods associated with hydrographic conditions. In total, 29 species of pteropods belonging to 10 genera and 5 families were identified, with mean abundance of 97.14 ± 66.16 ind./100 m3. The abundances and species number of pteropods exhibited apparent seasonal changes, abundance was higher in summer and lower during winter, while species numbers was higher in fall and lower in winter. Pteropods showed higher diversity in oceanic waters than in shallower shelf waters, but the abundance showed no significant difference. The night-time abundance and species number were significantly higher than the day-time. The effect of typhoon on the abundance and species numbers of pteropods was not significant. |
The four predominant species found in this study area were Creseis clava, Creseis acicula, Limacina inflate and Limacina trochiformis, together they accounted for 95% of the total pteropod catch, among these, C. clava constitued 48% of the total catch. The pteropod communition was similar among seasons, but ranked differently. Different dominant species showed different seasonal distribution patterns. The distribution of pteropods showed no clear spatial difference in the TS, but higher species richness was usually observed in the southern TS. The pteropods found in this study mostly belonged to the widespread oceanic species, and the dominant species were similar to the previous studies in the South China Sea. The total abundance, species number, and species diversity index of pteropods showed significantly positive correlation with the seawater temperature, and the species number was negative correlated with salinity. Among the four predominant species, the abundance of C. clava, C. acicula, and L. trochiformis were positively correlation with seawater temperature, meanwhile, C. acicula and L. trochiformis showed significantly negative correlations with salinity. This study proposed that the abundance, species number, and species diversity of Pteropods were not obviously influenced by typhoon, instead seasonal succession of water masses and day/night change might be the important factor affecting the distribution patterns of pteropods.