Population structure and growth of juvenile tri-spine horseshoe crabs released on the Kohnoshima tidal flat, Kasaoka, eastern Seto Inland Sea, Japan

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  • 岡山県笠岡市神島干潟に放流したカブトガニ幼生の個体群組成と成長

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<p>The tri-spine horseshoe crab Tachypleus tridentatus is endangered on the coasts of East Asia. A recovery program is being conducted in Kasaoka City, Okayama Prefecture, on the eastern Seto Inland Sea, Japan, using laboratory-bred horseshoe crabs released on the Kohnoshima tidal flat. To determine the most suitable instar stage for wild release, we analysed the distribution of carapace widths of juvenile horseshoe crabs observed on the tidal flat and estimated the growth rate at each instar. The results showed that juveniles grew up to the 9th instar stage in the 5th year after hatching on the tidal flat. Juveniles kept in our laboratory were smaller than juveniles living on the tidal flat, particularly at each of the 6.9th instar stages. We presume that poor food quality and high rearing density in captivity caused the lower growth rate of laboratory-reared juvenile horseshoe crabs. Releasing juveniles at early stages (< 5th instar) will improve growth and the success of the recovery program. Conservation measures will be required to maintain a sustainable wild population of horseshoe crabs in Kasaoka without relying on artificial releases.</p>

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Details 詳細情報について

  • CRID
    1390568456341463296
  • NII Article ID
    130007964563
  • DOI
    10.18960/hozen.2003
  • ISSN
    24241431
    13424327
  • Text Lang
    ja
  • Data Source
    • JaLC
    • CiNii Articles
  • Abstract License Flag
    Allowed

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