Meeting Abstract
In the subtropical coastal system of Hong Kong, salinity fluctuates dramatically (15.5 to 34 psu) during monsoon season and this fluctuation coincides with relatively high surface water temperature (~ 28°C) in summer. Their interactive effect was attributed to help curb the development and recruitment of the fouling tube worms based on laboratory based observations of Hydroides elegans. However, our field observations suggested that H. dirampha persisted during the summer months, and thus, we hypothesize that their early development may be less sensitive to the interactive stressor. We quantified larval survival, growth, clearance rate and settlement rate H. dirampha in a 2×3 factorial experiment (24 & 28°C; 20, 26, 32psu). Regardless of temperature, H. dirampha develops much slower or even fails to cleave under low salinity of 20. Under higher temperature (28°C), both embryo and larvae grow faster, but larval mortality increases. The larval growth, clearance and settlement rate of H. dirampha are significantly higher under medium salinity of 26. In contrast, the growth and settlement of sympatric congener H. elegans is negatively affected at the same salinity level. This work clearly illustrates how difference in larval physiological tolerance could shape abundances and distribution of a single species as well as community structure.
