Temperature and Estrogen Alter Predator-Prey Interactions between Fish Species.

Area of Science:

• Environmental toxicology
• Aquatic ecology
• Ecotoxicology

Background:

• Environmental estrogens are prevalent in waterways, impacting individual physiology.
• Limited understanding exists on how these pollutants affect species interactions.
• The influence of abiotic factors, like temperature, on contaminant effects is understudied.

Purpose of the Study:

• To investigate the effects of estrone (E1) and temperature on predator-prey interactions.
• To examine the combined impacts of E1 and temperature on fathead minnows and bluegill sunfish.
• To assess how E1 exposure influences predation mortality and predator success.

Main Methods:

• A factorial experiment exposed larval fathead minnows and adult bluegill sunfish to E1 or control.
• Fish were held at four seasonal temperatures (15°C, 18°C, 21°C, 24°C) for 30 days.
• Predation trials were conducted to measure minnow survival and sunfish prey-capture success.

Main Results:

• E1 exposure significantly increased fathead minnow mortality, irrespective of temperature.
• Minnow survival decreased from 74% (control) to approximately 50% with E1 exposure.
• Sunfish prey-capture success was reduced by E1 and showed an inverted U-shaped response to temperature, peaking at 21°C.

Conclusions:

• Organismal interactions are vulnerable to estrogenic pollutants.
• E1 disrupts predator-prey dynamics, increasing prey mortality while impairing predator efficiency.
• Risk assessments must incorporate food web interactions and environmental factors like temperature.