Burrow structure and utilization in the mudskipper Periophthalmodon septemradiatus from the Mekong Delta

Abstract

Several studies indicate that burrows play an essential role in burrowing fish, especially mudskippers, but little is known on burrow morphology and utilization of Periophthalmodon septemradiatus. This study was therefore conducted at five sampling sites from the estuary to upper reaches of Hau River to contribute to the knowledge of the behavior of Pn. septemradiatus, via in situ and ex situ observations of the utilization of burrow structures. Burrows made by polyester resin were used to determine their morphology. The male mudskippers Pn. septemradiatus were observed to excavate burrows using their mouths during the low tide. The burrows' shapes were found to be J, U and W, with 1-3 openings and one bulbous chamber. The chamber was used as egg container where the mudskipper deposits their fertilized eggs. W-shaped burrows were found to be interconnected chambers where the mudskipper used it to change direction of movements inside the burrow. For the J-and U-shaped burrows, the commonality at all five sites was identified. The W-shaped burrows were common and were only found at two sites (Long Duc and An Lac Tay). For the burrows' structure, the openings to the surface were oval, circular and bulbous in shape. Yet, there were variations between sites, and the burrows' size was similar during the dry and wet seasons. At different sites, the depth of the burrows seasonally changed. The burrows used by mudskipper provide shelter, spawning sites, and access to feeding grounds for other mudskipper species. 'Fish Use for conducting Research' singed by Vice Head of Department of Research Affairs on 8 th November 2018 for the study from April 2017 to April 2019. Burrow structureThe burrow structures of Pn. septemradiatus were studied in situ, by creating casts of burrows at field sites when the fish relocated out of burrows, to avoid polyester resin's effect on fish. The constructed burrows by Pn. septemradiatus were

Monthly variations in growth pattern and condition factor of Periophthalmodon septemradiatus (Gobiiformes: Periophthalminae) living along the Bassac River in Viet Nam

“…Likely, P. modestus in northern Viet Nam ( Tran, Nguyen & Ha, 2021b ) and P. gracilis in VMD ( Dinh et al, 2022c ) exhibited the seasonal change in growth pattern. The variation in abiotic ( e.g ., salinity and mudbank slope) and biotic ( e.g ., vegetation) factors between these five sampling sites ( Dinh et al, 2021 ) could lead to the spatial change in P. septemradiatus growth pattern. This assumption was also found in P. modestus in northern Viet Nam ( Tran, Nguyen & Ha, 2021b ) and P. gracilis in VMD ( Dinh et al, 2022c ).…”

Burrow behaviour, structure and utilization of the amphibious mudskipper Periophthalmus chrysospilos Bleeker, 1853 in the Mekong Delta

“…Mudskippers construct burrows in the mud substrate in riverine, estuarine and coastal regions (e.g., Parapocryptes [henceforth Pa. ] serperaster ( Dinh et al, 2014b ), Periopthalmodon [henceforth Pn. ] septemradiatus ( Dinh et al, 2021b ). In species such as Pa. serperasters ( Dinh et al, 2014a ), burrows are constructed and maintained at high tide while in Boleophthalmus [henceforth B. ]…”

“…schlosseri ( Tran et al, 2020 ) and Pn . septemradiatus ( Dinh et al, 2021b ), these are carried out when the mudflat is exposed during low tide.…”

“…The burrows of mudskippers and other gobioid fishes are well-defined; typically I-, J-, Y-, U- and W-shaped ( Atkinson and Taylor, 1990 , Ishimatsu et al, 2007 , Tran et al, 2020 , Dinh et al, 2021b ). Burrow shapes vary with habitat, e.g., Pn.…”

One size does not fit all: Variation in anatomical traits associated with emersion behavior in mudskippers (Gobiidae: Oxudercinae)

“…Traits associated with aquatic-terrestrial movement in fishes have been examined with respect to fin kinematics (Pace and Gibb, 2009), morphological and molecular basis of vision (Sayer, 2005;Hu et al, 2022), vasculatures of skin, gills, and buccoopercular cavities associated with respiration (Zhang et al, 2000;Gonzales et al, 2011), body elongation and compressions (Polgar et al, 2017;Egan et al, 2021), specialization in feeding and diet (Kruitwagen et al, 2007;Ord and Hundt, 2020;Tran et al, 2022), shifts in dominant bacteria in the gut (Guan et al, 2021), vocalizations (Polgar et al, 2011), burrowing behaviors (Ishimatsu et al, 1998;Dinh et al, 2021), candidate genes associated with emersion (You et al, 2014), and the effects of amphibious behavior on population structure (Corush et al, 2022). In many of these examples, multiple behavioral, physiological, and anatomical traits work together to allow fish to emerge.…”