M4 AM Endocrine Disruption in Fish
Monday, 14 November 2005: 8:00 AM - 11:40 AM in Ballroom 4

(VIN-1117-827482) Endocrine disruption in an estuarine fish, Gillichthys mirabilis: Linking reproductive parameters with sediment chemistry.

Vines, C¹, Anderson, S¹, Bennett, W¹, Teh, S¹, Denison, M¹, Baston, D¹, Hwang, H¹, Brooks, A², Cherr, G, ¹ University of California, Davis, Davis, CA, USA² University of California, Santa Barbara, Santa Barbara, CA, USA

ABSTRACT- The Pacific Estuarine Ecosystem Indicator Research Consortium (EPA, EaGLes program) has been developing a suite of biomarker responses in common, resident species of California estuaries as an integrative tool for determining overall wetland condition. As part of this project, we analyzed reproductive biomarker responses in the longjaw mudsucker, Gillichthys mirabilis, collected from or outplanted at marshes in Northern and Southern California. Gillichthys is a ubiquitous, indigenous species that utilizes burrows for reproduction, and as a result is exposed to contaminants through direct contact with sediment as well as absorption from water and food. While Gillichthys displays some vertical integration from channels to marsh plain, their limited home range provides valuable information on contaminant exposure at specific locations within marshes. Reproductive parameters measured were presence of choriogenins (egg shell proteins) in male/immature fish, gross and histological examination of gonads for abnormalities (ovotestis, tumors), and apoptosis in ovaries. A subset of fish were analyzed for tissue levels of organic contaminants, including PCBs, known endocrine disrupting compounds. Sediments collected from stations where fish were trapped or outplanted were analyzed for a variety of chemicals (PCBs, PAHs, metals, pesticides), and extracts of these sediments were utilized in a reporter gene mammalian cell bioassay specific for estrogenic activity. Fish collected from a known contaminated marsh in San Francisco Bay (Stege Marsh) exhibited increased numbers of male/immature fish with choriogenins, particularly at stations where the corresponding sediments contained high levels of PCBs and increased estrogenic potential. Fish outplanted at selected stations at Stege showed a similar trend, and also showed elevated levels of PCBs in tissues. There was also a higher incidence of ovotestes, gonadal tumors, and apoptosis at the contaminated marsh (Stege Marsh). Reproductive impairment in Gillichthys, including endocrine disruption, appears to be a useful indicator for toxicant stress on a native fish.

Key words: endocrine disruption, fish, choriogenins, sediment