Morphological and Reproductive Characteristics of Male Mosquitofish ( Gambusia affinis holbrooki ) Inhabiting Sewage-Contaminated Waters in New South Wales, Australia

Abstract

The potential effects of exposure of fish to reproductive endocrine disruptors (REDs) is of major concern. This study reports on the effects of sewage effluent exposure on morphology of male mosquitofish (Gambusia a. holbrooki) in a tributary of the Hawksbury-Nepean River system in New South Wales, Australia. The growth and development of the modified anal fin (the gonopodium, GP) is a secondary sexual characteristic in males, forms under the influence of testosterone, and is critical for sperm transfer. The GP was reduced in length in males sampled downstream from a sewage treatment plant discharge point compared to GP fin length in males upstream or from other comparison sites. The reduction in size of this androgen-dependent structure suggests the presence of RED substances in the water. The presence or absence of spermatozeugmata (sperm packet) was not related to a reduction in GP length, which suggests spermatogenesis may not be reduced, but other measures of fertility remain to be evaluated. These results are discussed in the context of RED contaminants associated with sewage effluent.

Monitoring of selected estrogenic compounds and estrogenic activity in surface water and sediment of the Yellow River in China using combined chemical and biological tools

“…One of the most reported biological effects is fish feminization found in various rivers (Angus et al, 2002;Harries et al, 1997;Jobling et al, 1998;Kristensen et al, 2007;Xie et al, 2010). The observed effects in fish include vitellogenin induction, abnormal development of gonads (Harries et al, 1997;Lye et al, 1997;Jobling et al, 2002) and secondary sexual characteristics (Batty and Lim, 1999;Xie et al, 2010), which have been linked to some estrogenic compounds in the effluents of sewage treatment plants (Harries et al, 1997;Jobling et al, 2002;Lye et al, 1997;Thorpe et al, 2003;Xie et al, 2010). These compounds include 4-t-octylphenol (4-t-OP), 4-nonylphenols (4-NP), bisphenol-A (BPA), estrone (E1), estradiol (E2) and triclosan (TCS), which have been demonstrated to have in vitro and/or in vivo estrogenic activities (Foran et al, 2000;Ishibahsi et al, 2004;Jobling and Sumpter, 1993;Jobling et al, 1995;Raut and Angus, 2010;Stasinakis et al, 2008).…”

Stimulation of reproductive growth in rainbow trout (Oncorhynchus mykiss) following exposure to treated sewage effluent

“…continuous exposure of aquatic organisms to low levels of potent hormones can have measurable effects, such as induction of vitellogenin in male 01' immature fish [8], alteratiol1s in steroid hormone levels [9], or changes in external reproductive characteristics [10]. Estrogenic substances most likely responsible for these observations have been weIl characterized in sewage effiuent [11].…”

Gonadosomatic Index and Testis Morphology of Common Carp (Cyprinus carpio) in Rivers Contaminated with Estrogenic Chemicals.

“…Many researches have been focused on fish, since as aquatic inhabitants they receive sewage or industrial effluent and agricultural runoff containing estrogenic chemicals [5,14,30]. In fish, estrogenic responses have been associated with exposure to pesticides [3,35], pulp mill effluents [23,29,34], plasticizers [19] and sewage effluent [2,17,31]. Abnormalities have also been reported in the male reproductive system of fish living in water polluted by sewage or industrial chemicals [12,25].…”