Reproduction in fish is the most significant life function affected by external stressors and provides an important link between the effects of hormonally-active compounds and reproductive success or failure of subsequent generations. Even among organisms that might physiologically be capable of successful fertilization, impairment of poorly understood behavioral cues often prohibits successful generation of offspring.

Our initial research used bonytail chub (Gila elegans) exposed to varying doses of treated effluent. Highly significant hormonal impairment was observed in fish housed in treatment tanks compared to control fish. We observed a generalized de-coupling, in treatment fish of either gender, of the normally inverse relationship between primary male and female sex hormones observed in the non-impaired, control population of fish. The highly significant impairment in treatment fish was observed in a system where concentrations of hormonally-active compounds were relatively quite low.

The focus of our current research is to quantify reproductive impairment in bonytail chub. We are collaborating with colleagues at USGS and using Polar Organic Chemical Integrative Samplers (POCIS) and Semipermeable Membrane Devices (SPMD’s) to quantify organic compounds which the treatment fish have been exposed. We will provide environmental stimulus to induce spawning and impairment in fertility or fecundity of the parent generation will be quantified. Fertilized eggs will be collected and the first filial generation will be raised in captivity for one year after which a suite of reproductive and developmental indicators will be assessed.