title: Roles of air stored in burrows of the mudskipper Boleophthalmus pectinirostris for adult respiration and embryonic development.
abstract: Air was stored in 90% of Boleophthalmus pectinirostris burrows in summer breeding months when fish were active on the mudflat surface during low tide but only in 50% of burrows in overwintering months when the fish confined themselves to burrows. The volume of gas recovered from the burrows ranged from 30 to > 400 ml. The partial pressure of oxygen (PO₂) of the gas varied from 5 to 20 kPa and was inversely related to the partial pressure of carbon dioxide (PCO₂) in all but the wintering periods. Sampling in July demonstrated that gas was stored in both male and female burrows with no difference in volume, PO₂ or PCO₂ between them. Adult fish were able to survive total submersion in hypoxic (PO₂ = 1.96 kPa) water for 8 h, but no embryos survived to hatch in the hypoxic aquatic environment. Thus, the deposited air appears to be a crucial source of oxygen for the embryos developing in the egg chamber of the burrow, but may play only a subsidiary role for adult respiration during presumed high-tide confinement.
authors.affiliation: Institute for East China Sea Research, Nagasaki University, 1551-7, Tairamachi, Nagasaki 851-2213, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Toba
authors.forename: A
authors.initials: A
authors.lastname: Ishimatsu
mesh_terms: D000388:Air / Q000032:analysis*; D000818:Animals; D002245:Carbon Dioxide / Q000032:analysis; D047108:Embryonic Development; D004777:Environment; D005260:Female; D005399:Fishes / Q000196:embryology* / Q000502:physiology*; D000860:Hypoxia; D008297:Male; D010100:Oxygen / Q000032:analysis; D012119:Respiration; D014867:Water / Q000032:analysis
chemical_list: D014867:Water; D002245:Carbon Dioxide; D010100:Oxygen
keywords: air deposition; burrow environment; hypoxia tolerance; overwintering