Newly molted juvenile horseshoe crab (left) and its old shell (right) on a tidal flat adjacent to mangroves in the Pearl Bay estuary (Guangxi, China). Photo: Chang-Po Chen

Fan LF, Chen CP, Yang MC, Qiu G, Liao YY, Hsieh HL


Ontogenetic changes in dietary carbon sources and trophic position of two co-occurring horseshoe crab species in southwestern China

Populations of Asian horseshoe crabs have severely declined in the South and East China Seas. To better protect them, critical habitats need to be defined. Fan et al. used stable isotope analyses to evaluate ontogenetic changes in dietary carbon sources and trophic position for Tachypleus tridentatus and Carcinoscorpius rotundicauda in a mangrove- and seagrass-vegetated estuary in southwestern China. Their results show that seagrass contributed most to dietary carbon of both species (~60%) and that trophic position did not differ among different instar stages (instar 5–6 up to adults). Thus, in addition to protecting habitats for their value as horseshoe crab nursery areas, efforts to protect dietary sources such as seagrass meadows would improve strategies for conserving Asian horseshoe crabs.


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