Changes in the distributions of juvenile horseshoe crabs (Arthropoda: Chelicerata) (2002–2014) related to environmental perturbations at Pak Nai and Ha Pak Nai, Deep Bay, Hong Kong SAR, China

Nursery habitat for Asian horseshoe crabs along the northern Beibu Gulf, China: Implications for conservation management under baseline gaps

“…Based on the preliminary results from fisherman questionnaire surveys (Liao, Hsieh, et al, ), the first indication of nursery habitat distribution along the northern Beibu Gulf shoreline was provided, and 14 and 10 active nursery grounds for T. tridentatus and C. rotundicauda , respectively were identified through a programme of systematic sampling. Our findings support the claim that Beibu Gulf is the most suitable habitat for T. tridentatus , as six out of 14 nursery grounds in the northern Beibu Gulf had higher population densities (> 2.0 individuals/100 m 2 , Table ) than recorded in Hong Kong (Kwan et al, ; Lee & Morton, ). Our findings, however, could not be further compared with the available datasets from Taiwan, Singapore, the Philippines (Almendral & Schoppe, ; Kaiser & Schoppe, ), and Indonesia (Anggraini, Bengen, & Natih, ) which utilised different sampling methods.…”

“…To overcome this limitation, the identification of critical nursery and spawning habitats for the Asian horseshoe crabs, therefore, can be considered as the first important step (International Union for Conservation of Nature, 2012). To date, territorial-wide investigations have been conducted in Hong Kong (Kwan et al, 2016;Lee & Morton, 2016;Shin et al, 2009), Taiwan (Chen, Yeh, & Lin, 2004; (Anggraini, Bengen, & Natih, 2017) which utilised different sampling methods.…”

“…To overcome this limitation, the identification of critical nursery and spawning habitats for the Asian horseshoe crabs, therefore, can be considered as the first important step (International Union for Conservation of Nature, 2012). To date, territorial‐wide investigations have been conducted in Hong Kong (Kwan et al, ; Lee & Morton, ; Shin et al, ), Taiwan (Chen, Yeh, & Lin, ; Hsieh & Chen, ) and Singapore (Cartwright‐Taylor, Von Bing, Chi, & Tee, ) to indicate essential nursery habitats of Asian horseshoe crabs. It is now sufficiently clear that there are limited numbers of actively utilized nursery areas of Asian horseshoe crabs in Hong Kong (i.e.…”

“…Similar to many living fossils, these species exhibit slow growth, low dispersal rates, long life span, small home range and delayed reproductive development (Hu, Kwan, Wang, Cheung, & Shin, ; Kwan, Shin, & Cheung, ; Sekiguchi, ). These life‐history characteristics render them vulnerable to habitat degradation (Nelson et al, ; Tripathy, Sivakumar, Sajan, Satyaranjan, & Choudhury, ), habitat loss (Hsieh & Chen, ; Lee & Morton, ), and over‐exploitation for human consumption and bleeding (Fu et al, ; Liao, Hsieh, et al, ; Shin, Li, & Cheung, ). Li, Xie, and Kwan () estimated that at least 100,000 pairs of tri‐spine horseshoe crabs, Tachypleus tridentatus , are bled annually to support endotoxin contamination tests of injectable drugs as specified in the Chinese Pharmacopeia.…”

“…American horseshoe crabs have demonstrated to be selective in their choice of spawning and nursery habitats (Fulford & Haehn, 2012;Medina & Tankersley, 2010). For Asian horseshoe crabs, a great deal of attention has been devoted to documenting declining juvenile recruitments Lee & Morton, 2016;Liao, Hsieh, et al, 2019;Weng et al, 2012).…”