Selenium impacts on razorback sucker, Colorado River, Colorado II. Eggs

Area of Science:

• Environmental toxicology
• Aquatic ecology
• Conservation biology

Background:

• Razorback sucker (Xyrauchen texanus) is an endangered species in the Colorado River basin.
• Flooded bottomland sites near Grand Junction, Colorado, are potential sources of selenium contamination.

Purpose of the Study:

• To determine the effects of selenium exposure on razorback sucker egg hatching and development.
• To assess the correlation between selenium concentrations and reproductive success in razorback suckers.

Main Methods:

• Adult razorback suckers were exposed to selenium for 9 months.
• Fertilized eggs were collected and analyzed for inorganic elements.
• A 9-day egg study was conducted using reference water and site-specific waters.
• Egg viability, survival, hatchability, and larval deformities were assessed.

Main Results:

• Selenium concentrations varied significantly among sampling sites, with Adobe Creek showing the highest levels.
• No significant differences in viability, survival, or hatchability were observed across different water sources.
• Adobe Creek larvae exhibited higher rates of deformities when incubated in site water compared to reference water.
• Negative correlations were found between adult muscle selenium concentrations and percent hatch, egg diameter, and embryo deformities.

Conclusions:

• Selenium contamination in the upper Colorado River basin is a significant concern for razorback sucker recovery efforts.
• Elevated selenium levels can negatively affect reproductive parameters, potentially hindering population recovery.
• Further research and mitigation strategies are needed to address selenium contamination and support endangered fish recovery.