Ecosystem Alteration by Mosquitofish (Gambusia affinis) Predation

Area of Science:

• Aquatic Ecology
• Limnology
• Invasive Species Biology

Background:

• Artificial aquatic ecosystems are susceptible to biological alterations.
• Introduction of non-native species can disrupt established food webs.
• Understanding predator-prey dynamics is crucial for managing aquatic environments.

Purpose of the Study:

• To investigate the ecological impact of Gambusia affinis on artificial pool ecosystems.
• To assess the cascading effects of G. affinis predation on lower trophic levels.
• To document changes in water chemistry and community structure.

Main Methods:

• Controlled introduction of Gambusia affinis into artificial pools.
• Monitoring of zooplankton (rotifer, crustacean) and insect populations.
• Measurement of phytoplankton density, water optical transmissivity, and temperature.
• Analysis of dissolved inorganic and organic phosphorus concentrations.
• Identification and quantification of annelid species.

Main Results:

• Gambusia affinis significantly reduced rotifer, crustacean, and insect populations.
• Extraordinary phytoplankton development occurred, reaching 2x10(8) cells/mL.
• Water optical transmissivity decreased, while water temperature increased.
• Dissolved inorganic phosphorus levels decreased, with a corresponding rise in dissolved organic phosphorus.
• Spirogyra growth was inhibited, and Chaetogaster was replaced by Aeolosoma.

Conclusions:

• Gambusia affinis acts as a potent predator, restructuring artificial aquatic communities.
• Predation by G. affinis can lead to trophic cascades, promoting algal blooms.
• The introduction of G. affinis alters key physical and chemical parameters of artificial aquatic habitats.
• Ecological shifts observed highlight the significant impact of invasive predators on aquatic ecosystems.