title: Ventilatory and behavioural responses of the marbled sole Pseudopleuronectes yokohamae to progressive hypoxia.
abstract: This study identified ventilatory and behavioural responses in the marbled sole Pseudopleuronectes yokohamae under experimentally induced progressive decreases in dissolved oxygen (DO) levels. Ventilation frequency showed an increase with decreasing DO levels from normoxia to 2·75 mg O2l-1, followed by a decrease in ventilation frequency at decreased DO levels from 2·00 to 0·75 mg O2l-1. At DO levels below 2·00 mg l-1, behaviours at the bottom were suppressed, whereas avoidance behaviours increased. A decrease in avoidance behaviours was observed from 1·00 to 0·75 mg O2l-1. Upside-down reversal and incapacitation at DO levels of 1·00-0·75 mg O2l-1suggested that sublethal effects on P. yokohamae were induced. The responses observed before the sublethal DO level could be interpreted as an effort to maintain oxygen uptake, reduce routine activities and facilitate avoidance. The observed DO level thresholds that induce behavioural responses, in addition to sublethal effects, indicate hypoxia-tolerance that is important for understanding the effects of hypoxia on coastal ecosystems.
authors.affiliation: Graduate School of Informatics, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nishizawa
authors.affiliation: Faculty of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kono
authors.affiliation: Field Science Education and Research Center, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.|CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Arai
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Hiroshima, 739-8528, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Shoji
authors.affiliation: Graduate School of Informatics, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501, Japan.|CREST, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mitamura
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D005432:Flounder / Q000502:physiology*; D000860:Hypoxia / Q000662:veterinary; D010100:Oxygen / Q000032:analysis*; D012119:Respiration; D012623:Seawater / Q000737:chemistry
chemical_list: D010100:Oxygen
keywords: avoidance; dissolved oxygen; flatfish; hypoxia; normoxia; ventilation frequency