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.

Morphology of the respiratory vasculature of the mudskipper Boleophthalmus pectinirostris (Gobiidae: Oxudercinae)

“…During high tide in warm months, Boleophthalmus pectinirostris retreat into their burrow, and are probably exposed to severe aquatic hypoxia (monthly average PO 2 of burrow water from March to October ranges from 0.5 to 4.4 kPa) for several hours, usually twice a day (Toba & Ishimatsu, 2014). From early November to early March (monthly average PO 2 from November to February ranges from 2.8 to 8.8 kPa), the fish overwinter inside the burrow, remaining in the burrow for several months.…”

“…The fish appears to remain inside its burrow during high tide in these months. The burrow is filled with hypoxic water [yearly average O 2 partial pressure (PO 2 ) 2.9 kPa, monthly average PO 2 ranges from 0.2 to 18.6 kPa, Toba & Ishimatsu, 2014], and contains a volume of air, which is however of relatively minor importance for adult survival during high‐tide burrow confinement (Toba & Ishimatsu, 2014). From early December to early March, B. pectinirostris overwinter in a burrow that the fish excavate prior to overwintering (Kobayashi et al, 1971; Takegaki et al, 2006).…”

Early life history of oxudercine gobyPseudapocryptes elongatusin the Mekong Delta, Vietnam

“…Although the air-breathing capacity of adult P. elongatus strongly indicates their likely occurrence in hypoxic, stagnant, inland brackish waters, the otolith Sr:Ca analyses revealed that larval hatching undoubtedly takes place in the marine environment. Inferring from the reproductive strategy of other oxudercine gobies ( Periophthalmus modestus , Ishimatsu et al ., 2007; Periophthalmus minutus , Takeda et al ., 2011; Periophthalmodon schlosseri , Ishimatsu et al ., 2009; and Boleophthalmus pectinirostris , Hong et al ., 2007; Toba & Ishimatsu, 2014), it may be hypothesized that spawning of P. elongatus occurs in burrows excavated in soft, fine sediment in coastal mudflats.…”

Pengaruh Liang Boleophthalmus pectinirostris (Linnaeus, 1758) (Actinopterygii:Gobiidae) terhadap Biomassa Mikrofitobenthos di Ekosistem Mangrove Pandansari Brebes Jawa Tengah

“…Beberapa jenis dari ikan gelodok membangun liang (Clayton, 1993) dengan bentuk yang berbeda beda. Fungsi liang sebagai tempat berlindung dari pemangsa (Clayton, 1993), tempat memyimpan telur (Ishimatsu and Graham, 2011), tempat menyimpan oksigen untuk menghindari keadaan hypoxia (Toba and Ishimatsu, 2014), dan termoregulator (Yang, Lee and Williams, 2003;Ansari et al, 2014). Jenis Boleophthalmus boddarti (pallas), Scarteleos viridis dan B. pectinirostris selain membangun liang juga membangun dinding lumpur (Clayton and Vaughan, 1988;Yang, Lee and Williams, 2003;Chen et al, 2007) sebagai pagar agar daerah teritorialnya tidak dimasuki oleh ikan gelodok lain.…”