title: Disturbance of recruitment success of mantis shrimp in Tokyo Bay associated with effects of hypoxia on the early life history.
abstract: We investigated effects of severe hypoxia (dissolved oxygen <1 ml l(-1)) on recruitment of mantis shrimp Oratosquilla oratoria in Tokyo Bay. Ten-year field surveys were conducted to examine quantitative relationships in annual mean densities of larvae and juveniles, and spatial distribution of juveniles and severe hypoxia. There was no significant correlation between annual mean densities of larvae and juveniles, suggesting that mortality during larval or juvenile stages varies among years, which might have regulated abundance of young-of-the-year juveniles. Juvenile density was low in the severely hypoxic area, implying that hypoxia could affect survivals and spatial distribution of juveniles. Meanwhile, there are yearly fluctuations in juvenile density in normoxic areas of both northern and southern part of the bay. This evidence suggests that abundance of post-settled juveniles might have been determined by not only effects of hypoxia, but also other factors influencing mortality during the early life stages.
authors.affiliation: Center for Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan. Electronic address: kodama.keita@nies.go.jp.
authors.forename: Keita
authors.initials: K
authors.lastname: Kodama
authors.affiliation: Kanagawa Prefectural Fisheries Technology Center, Miura, Kanagawa 238-0237, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tajima
authors.affiliation: Kanagawa Prefectural Fisheries Technology Center, Miura, Kanagawa 238-0237, Japan.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: Tokyo Bay Fisheries Laboratory, Chiba Prefectural Fisheries Research Center, Futtsu, Chiba 293-0042, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ohata
authors.affiliation: Center for Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shiraishi
authors.affiliation: Center for Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Horiguchi
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D061006:Bays / Q000737:chemistry; D001522:Behavior, Animal; D003445:Crustacea / Q000378:metabolism / Q000502:physiology*; D007814:Larva / Q000378:metabolism / Q000502:physiology; D008018:Life Cycle Stages; D010100:Oxygen / Q000032:analysis* / Q000378:metabolism; D011156:Population Density; D014041:Tokyo
chemical_list: D010100:Oxygen
keywords: Early life history; Hypoxia; Oratosquilla oratoria; Population dynamics; Reproduction; Tokyo Bay