title: Aquatic hypoxia is an disrupter 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.
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong. bhrswu@cityu.edu.hk
authors.forename: Rudolf S S
authors.initials: RS
authors.lastname: Wu
authors.forename: Bing Sheng
authors.initials: BS
authors.lastname: Zhou
authors.forename: David J
authors.initials: DJ
authors.lastname: Randall
authors.forename: Norman Y S
authors.initials: NY
authors.lastname: Woo
authors.forename: Paul K S
authors.initials: PK
authors.lastname: Lam
mesh_terms: D000818:Animals; D002347:Carps / Q000502:physiology*; D004703:Endocrine System / Q000502:physiology; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D007814:Larva; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D012098:Reproduction; D013534:Survival; D013739:Testosterone / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D014876:Water Pollution / Q000009:adverse effects*
chemical_list: D014284:Triiodothyronine; D013739:Testosterone; D004958:Estradiol; D010100:Oxygen