Aquatic Hypoxia Is an Endocrine Disruptor and Impairs Fish Reproduction

Abstract

There is increasing concern that certain chemicals in the aquatic environment can disrupt endocrine systems, leading to reproductive impairment and threatening survival of wild populations of invertebrates, fish, bird, reptiles, and wildlife. For the first time, we report that hypoxia is also an endocrine disruptor and poses a significant threat to the reproduction and hence sustainability of fish populations. Serum levels of testosterone, estradiol, and triiodothyronine significantly decreased in carp (Cyprinus carpio) upon chronic exposure to hypoxia. These hormonal changes were associated with retarded gonadal development in both male and female carp, reduced spawning success, sperm motility, fertilization success, hatching rate, and larval survival, indicating that adverse effects of hypoxia on reproductive performance resulted from endocrine disruption. Since aquatic hypoxia commonly occurs over thousands of square kilometers in aquatic systems worldwide, our results imply that endocrine disruption and reproductive impairment in fish may be a widespread environmental problem.

Acute and chronic effects of testosterone and 4-hydroxyandrostenedione to the crustacean Daphnia magna

“…Agricultural and other anthropogenic activities are principal non-point sources for steroid hormones in water and sediment systems (Kolpin et al, 2002). With the increasing significance of EDs on environmental health (Desbrow et al, 1998;Wu et al, 2003) the concern about the potential negative ecological effects of steroid hormones has resulted in an increased interest regarding the occurrence, distribution, mobility and persistence of these compounds in soils, sediments and water systems (Ying et al, 2002).…”

Endocrine, biotransformation, and oxidative stress responses in salmon hepatocytes exposed to chemically induced hypoxia and perfluorooctane sulfonamide (PFOSA), given singly or in combination

“…There is a growing concern about the effects of global warming leading to reduction in oxygen content in several aquatic environments (Obenour et al 2012;Scavia et al 2013; Thomas and Rahman 2012). Previously, the alteration of biotransformation and hormonal systems by hypoxia has been reported in both in vivo and in vitro studies (du Souich and Fradette 2011; Shang et al 2006;Wu et al 2003). In addition, hypoxia has been shown to produce cellular oxidative stress responses in several fish species (Clotfelter et al 2013;Gnaiger et al 1995;Mansfield et al 2005;Olsvik et al 2013).…”

“…The relative importance of environmental hypoxia on organismal adaptive abilities to chemical insult is not well understood. Oxygen availability is essential for normal physiological function, and hypoxia has been associated with effects on hormonal and biotransformation systems (Shang et al 2006;Wu 2009;Wu et al 2003).…”

Vitreoscilla Hemoglobin (VHb) Overexpression Increases Hypoxia Tolerance in Zebrafish (Danio rerio)

“…Other environmental factors, such as temperature, circadian rhythm, seasonal change, and eutrophication, can cause hypoxia in water bodies. Because hypoxia can cause mortality, reduce growth rates, induce endocrine disruption, and alter distributions and behaviors of fish, it can lead to large reductions in the abundance, diversity, and harvest of various species within affected waters (Breitburg 2002;Wu 2002Wu , 2003Shang and Wu 2004;Thomas et al 2007). Therefore, it becomes very important to find ways to cultivate new fish lines with hypoxia tolerance in aquaculture.…”