Conservation program for the Asian horseshoe crab Tachypleus tridentatus in Taiwan: characterizing the microhabitat of nursery grounds and restoring spawning grounds

摘要: A study of the physical properties horseshoe crab (Tachypleus tridentatus) nursery grounds indicated that juveniles preferred sediments consisting fine sand with median grain size 0.14–0.27 mm in diameter, 16.9–23.2% water content when tides receded, 0.23–0.41% TOC content, 0.04–0.07% TN 2.3–2.8 µg/cm2 chlorophyll a and poorly sorted substrates. Juvenile density increased based on amount sediment infaunal polychaete density, suggesting prefer containing abundant prey its supporting food web. An effort to restore spawning was conducted by covering 20 cm deep mud substrate (0.23 diameter) coarse (1.10 diameter). Although adults transferred this site succeeded laying eggs, hatching rate only 33.9%. This low may be attributed small tidal amplitude at restoration site.