Land Invasion by the Mudskipper, Periophthalmodon septemradiatus, in Fresh and Saline Waters of the Mekong River

Abstract

There has been a long-standing controversy about whether vertebrates emerged in the Paleozoic from marine or freshwater environments. Several hypotheses have proposed coastal, estuarine and riparian areas as sites of the transition. Here, we report the ecology of an amphibious fish Periophthalmodon septemradiatus, which we presume is in the process of niche expansion into terrestrial habitats from estuarine to freshwater environments along the Mekong River, Vietnam. Adult fish are highly terrestrial and have not been observed to venture into water during our survey. Courtship behaviour was observed, and fertilised eggs were recovered from burrows in both brackish and freshwater environments. The smallest fish collected at 12, 96, and 148 km from the river mouth were juveniles shortly after starting an amphibious life. These findings suggest reproduction in both brackish and freshwater environments. In contrast, otolith Sr:Ca ratio indicates larval hatching only in brackish water. Analysis of a 940-base pair (bp) segment of the mitochondrial cytochrome c oxidase subunit II and a 934-bp segment of the mitochondrial D-loop demonstrated no genetic segregation between populations. The fish may provide a unique opportunity to study how ambient salinity affects the biology and ecology of a living vertebrate during transition from water to land.

Short Communication: Density and length-weight relationship of mudskipper (Periophthalmus spp.) in the mangrove area of Kairatu Beach, Maluku, Indonesia

“…Nevertheless, Ravi (2011) reports that mudskipper can survive in mangrove areas with a salinity range of 23.5-32.8 ‰. According to Mai et al (2019) that salinity affects the life of mudskippers in their habitat.…”

High‐throughput metabolomics method based on liquid chromatography‐mass spectrometry: Insights into the underlying mechanisms of salinity–alkalinity exposure‐induced metabolites changes in Barbus capito

“…But, a large amount of them have not been utilized by fisheries, and the research on fish culture in saline‐alkali waters needs further breakthrough. Research on salt and alkali tolerance of fish has been carried out relatively late, which most of the resistance studies have performed using conventional physiological and biochemical studies [31, 32]. Although high salinity in water have different physical and chemical effects and toxic effects on fish, Barbus capito can still grow and reproduce normally in a certain concentration of saline‐alkali environment.…”

“…But, a large amount of them have not been utilized by fisheries, and the research on fish culture in saline-alkali waters needs further breakthrough. Research on salt and alkali tolerance of fish has been carried out relatively late, which most of the resistance studies have performed using conventional physiological and biochemical studies [31,32]. excellent salt-and-alkali-resistant has become a better experimental materials for research on fish germplasm resources and salt and alkali tolerance mechanisms [33].…”

Mudskipper Fish as a Bio-indicator for Heavy Metals Pollution in a Coastal Wetland

“…Adult fish are strongly terrestrial and have not been observed to venture into the water. Courtship activity was observed and fertilized eggs were retrieved from burrows in both the brackish and freshwater habitats (Mai et al, 2019). In intertidal habitats, mudskippers can achieve densities of >4 individuals/m 2 (Polgar, 2012).…”