Hypersalinity drives physiological and morphological changes in Limia perugiae (Poeciliidae)

Abstract

A fundamental question in biology is how an organism's morphology and physiology are shaped by its environment. Here, we evaluate the effects of a hypersaline environment on the morphology and physiology of a population of livebearing fish in the genus Limia (Poeciliidae). We sampled from two populations of Limia perugiae (one freshwater and one hypersaline) in the southwest Dominican Republic. We evaluated relative abundance of osmoregulatory proteins using western blot analyses and used a geometric morphometric approach to evaluate fine-scale changes to size and shape. Our data show that gill tissue isolated from hypersaline fish contained approximately two and a half times higher expression of Na+/K+ ATPase proteins. We also show evidence for mitochondrial changes within the gills, with eight times more complex I and four times higher expression of ATP synthase within the gill tissue from the hypersaline population. The energetic consequences to Limia living in saline and hypersaline environments may be a driver for phenotypic diversity, reducing the overall body size and changing the relative size and shape of the head, as well as impeding the growth of secondary sex features among the males.

A new livebearing fish of the genus Limia (Cyprinodontiformes: Poeciliidae) from Lake Miragoane, Haiti

“…Specifically, Hispaniola is considered to be a radiation centre for this genus since 17 species are currently recognized as valid from this island whereas only one endemic species is reported from Cuba, Jamaica and Grand Cayman (Burgess & Franz, ; Chambers, ; Rodriguez, ; Weaver et al ., ). Although Limia is considered a freshwater fish genus, some species are tolerant to varying salinity levels and may even be found in hypersaline coastal lagoons (Haney & Walsh, ; Weaver et al ., ). However, most species occur in inland waters, including species locally distributed in mountain streams.…”

Effect of salinity acclimation on osmoregulation, oxidative stress, and metabolic enzymes in the invasive Xenopus laevis

“…Salinity is a critical environmental driver in the acclimatization capacity of many aquatic animals, thus modulating many traits of their biology such as growth rate, reproductive success, behaviour and survival (Montory, Pechenik, Diederich, & Chaparro, 2014; Rivera‐Ingraham & Lignot, 2017; Weaver et al, 2016). Changes in salinity generally induces an increase in the metabolic cost because of an enhanced energetic demand for transmembrane ion transport, synthesis of osmoactive molecules and blood pumping.…”

Elevational gradients do not affect thermal tolerance at local scale in populations of livebearing fishes of the genusLimia(Teleostei, Poeciliidae)

“…Limia fishes are one of the most dominant groups in freshwater ecosystems in the Caribbean with at least 19 endemic species on Hispaniola and one endemic species each occurring in Cuba, Jamaica, and Grand Cayman (Burgess and Franz, 1989; Rodriguez, 1997; Hamilton, 2001; Rodriguez-Silva et al ., 2020). These freshwater fishes occur in a wide distribution range occupying diverse aquatic habitats on these islands (Weaver et al ., 2016 a). Although the altitudinal distribution of freshwater fish species in general is known to be considerably more constrained than in terrestrial species by several factors including for example productivity, physicochemical characteristics of the water and others (Jaramillo-Villa et al ., 2010; Graham et al ., 2014; Carvajal-Quintero et al ., 2015), differences in altitudinal distribution in species of the genus Limia can be observed in natural habitats.…”