Direct evidence for aerial egg deposition in the burrows of the Malaysian mudskipper, Periophthalmodon schlosseri

Abstract

The presence of mudskipper eggs in an air-filled chamber was confirmed by direct endoscopic observation of intact burrows of Periophthalmodon schlosseri in a mudflat in Penang, Malaysia. For all five burrows from which video images of egg chambers were successfully obtained, the presence of air was unequivocally demonstrated by the existence of an air-water interface inside the chambers. Of these burrows, eggs were found in two, but not in the others. Eggs were laid uniformly in a monolayer on the inner top surface of the chamber. The much brighter color of the surface mud of the egg chambers than the surrounding mud, irrespective of the presence or absence of the eggs, suggested that the surface mud had been oxidized by deposited air.

Ecology of the Australian mudskipper Periophthalmus minutus, an amphibious fish inhabiting a mudflat in the highest intertidal zone

“…Periophthalmodon schlosseri (Ishimatsu et al 2009). We were unable to confirm whether air occurs in 347 P. minutus burrows, since the hard substratum did not allow us to apply the gas-collection method used 348 for P. modestus or Pn.…”

Roles of air stored in burrows of the mudskipper Boleophthalmus pectinirostris for adult respiration and embryonic development

“…pectinirostris burrows provided an oxygen reservoir for burrow‐dwelling fish and for developing embryos. The subsequent studies substantiated that embryos developed in air stored and replenished by burrow‐tending males (Ishimatsu et al , , ), but they succumbed within 2 days if incubated in hypoxic water simulating typical burrow‐water conditions (Ishimatsu et al , ). In contrast, the role of stored air as an oxygen reservoir for burrow‐dwelling fish had remained elusive.…”

“…The vertical dimension ( H B ) and the number of openings ( N BO ) were also determined. Because a horizontal plane of casts could represent an interface between burrow water and stored gas (Ishimatsu et al , ), the number of horizontal planes ( N HP ) was counted, and areas of individual planes were measured with an image analysing software (Scion Image Beta 4.0.2; http://scion-corporation.software.informer.com/).…”

“…It was first discovered for the Malaysian mudskipper Periophthalmodon schlosseri (Pallas 1770) that their burrows contained a volume of gas with varying concentrations of O 2 and CO 2 (Ishimatsu et al , ). More recently, Ishimatsu et al () confirmed by an endoscope that the egg chambers of P . schlosseri burrows were filled with air and that embryos developed on the inner top surface of the air‐filled chamber.…”

Growth and body condition variation of the giant mudskipper Periophthalmodon schlosseri in dry and wet seasons

“…This gobiid species builds burrows in the estuarine mudflats for refuging, storing oxygen and laying eggs during the spawning season [13,14,15]. This fish actively transports NH 4 + against a concentration gradient [31] and uses air for respiring through its skin [35].…”